Photodynamic Therapy with an Association of Methylene Blue and Toluidine Blue Promoted a Synergic Effect against Oral Squamous Cell Carcinoma.

Among the most malignant cancers, oral squamous cell carcinoma (OSCC) stands out as the most common malignant head and neck tumor. Despite advances in the field of treatment, the prognosis of patients with OSCC remains poor. Aiming to overcome the limitations of the currently existing therapies against OSCC, the present work aims to investigate the potential of photodynamic therapy (PDT) with phenothiazine derivatives used alone or in combination. The incorporation of methylene blue (MB) and toluidine blue (TB) was evaluated in OSCC cell lines (HSC-3 and SCC-9) and a nontumor cell line (Hfib). Both compounds exhibited concentration and time-dependent incorporation, with higher rates observed in tumor cells. Regarding dark-phase cytotoxic activity, SCC-9 cells were the most sensitive cell line with an IC50 value of 362.6 µM and 41.4 µM for MB and TB, respectively. Using PDT, all lineages showed greater sensitivity, presenting lower IC50 values when compared to the dark phase values. The combination index values of 0.69 (dark phase) and 0.73 (clear phase) associated with concave isobolograms, in both phases, revealed that MB and TB have synergistic effects when combined against SCC-9 cells. These findings suggest that MB or TB assisted with PDT holds promise for OSCC treatment.

Mitochondrial dysfunction mediates neuronal cell response to DMMB photodynamic therapy.

Photodynamic therapy (PDT) is a process in which a photosensitizer (PS) is exposed to specific wavelengths and generates reactive oxygen species (ROS) which act within nanometers. The low invasive nature and directed cytotoxicity of this approach render it attractive to the treatment of different conditions, including the ones that affect the central nervous system (CNS). The effect of PDT on healthy neurons is one main concern over its use in the CNS, since neuronal-like cells were shown to be particularly sensitive to certain PSs. Among available PSs, 1,9-dimethyl-methylene blue (DMMB) stands out as being resistant to reduction to its inactive leuco form and by being able to produce high levels of singlet­oxygen. In this study, we aimed to investigate DMMB photodamage mechanisms in the hippocampal cell line HT22. Our results demonstrate that DMMB-PDT decrease in cell viability was linked with an increase in cell death and overall ROS production. Besides, it resulted in a significant increase in mitochondrial ROS production and decreased mitochondria membrane potential. Furthermore, DMMB-PDT significantly increased the presence of acidic autolysosomes, which was accompanied by an increase in ATG1 and ATG8 homologue GaBarap1 expression, and decreased DRAM1 expression. Taken together our results indicated that mitochondrial and autophagic dysfunction underlie DMMB-PDT cytotoxicity in neuronal cells.

The Potential of Phenothiazines against Endodontic Pathogens: A Focus on Enterococcus-Candida Dual-Species Biofilm.

Persistent apical periodontitis occurs when the endodontic treatment fails to eradicate the intraradicular infection, and is mainly caused by Gram-positive bacteria and yeasts, such as Enterococcus faecalis and Candida albicans, respectively. Phenothiazines have been described as potential antimicrobials against bacteria and fungi. This study aimed to investigate the antimicrobial potential of promethazine (PMZ) and chlorpromazine (CPZ) against E. faecalis and C. albicans dual-species biofilms. The susceptibility of planktonic cells to phenothiazines, chlorhexidine (CHX) and sodium hypochlorite (NaOCl) was initially analyzed by broth microdilution. Interaction between phenothiazines and CHX was examined by chequerboard assay. The effect of NaOCl, PMZ, CPZ, CHX, PMZ + CHX, and CPZ + CHX on biofilms was investigated by susceptibility assays, biochemical and morphological analyses. Results were evaluated through one-way ANOVA and Tukey's multiple comparison post-test. PMZ, alone or in combination with irrigants, was the most efficient phenothiazine, capable of reducing cell counts, biomass, biovolume, carbohydrate and protein contents of dual-species biofilms. Neither PMZ nor CPZ increased the antimicrobial activity of CHX. Further investigations of the properties of phenothiazines should be performed to encourage their use in endodontic clinical practice.

Tau Protein Aggregation in Alzheimer's Disease: Recent Advances in the Development of Novel Therapeutic Agents.

Major research in Alzheimer's disease (AD) related to disease-modifying agents is concentrated on pharmacological approaches related to diagnostic markers, neurofibrillary tangles and amyloid plaques. Although most studies focus on anti-amyloid strategies, investigations on tau protein have produced significant advances in the modulation of the pathophysiology of several neurodegenerative diseases. Since the discovery of phenothiazines as tau protein aggregation inhibitors (TAGIs), many additional small molecule inhibitors have been discovered and characterized in biological model systems, which exert their interaction effects by covalent and noncovalent means. In this paper, we summarize the latest advances in the discovery and development of tau aggregation inhibitors using a specialized approach in their chemical classes. The design of new TAGIs and their encouraging use in in vivo and clinical trials support their potential therapeutic use in AD.

Competition Between Phenothiazines and BH3 Peptide for the Binding Site of the Antiapoptotic BCL-2 Protein.

The study of proteins and mechanisms involved in the apoptosis and new knowledge about cancer's biology are essential for planning new drugs. Tumor cells develop several strategies to gain proliferative advantages, including molecular alterations to evade from apoptosis. Failures in apoptosis could contribute to cancer pathogenesis, since these defects can cause the accumulation of dividing cells and do not remove genetic variants that have malignant potential. The apoptosis mechanism is composed by proteins that are members of BCL-2 and cysteine-protease families. BH3-only peptides are the "natural" intracellular ligands of BCL-2 family proteins. On the other hand, studies have proved that phenothiazine compounds influence the induction of cellular death. To understand the characteristics of phenothiazines and their effects on tumoral cells and organelles involved in the apoptosis, as well as evaluating their pharmacologic potential, we have carried out computational simulation with the purpose of relating the structures of the phenothiazines with their biological activity. Since the tridimensional (3D) structure of the target protein is known, we have employed the molecular docking approach to study the interactions between compounds and the protein's active site. Hereafter, the molecular dynamics technique was used to verify the temporal evolution of the BCL-2 complexes with phenothiazinic compounds and the BH3 peptide, the stability and the mobility of these molecules in the BCL-2 binding site. From these results, the calculation of binding free energy between the compounds and the biological target was carried out. Thus, it was possible to verify that thioridazine and trifluoperazine tend to increase the stability of the BCL-2 protein and can compete for the binding site with the BH3 peptide.

Antifungal activity of promethazine and chlorpromazine against planktonic cells and biofilms of Cryptococcus neoformans/Cryptococcus gattii complex species.

Cryptococcus neoformans/Cryptococcus gattii are fungal pathogens that affect the central nervous system, mainly in immunocompromised individuals. Due to the limited pharmacological arsenal available for the treatment of cryptococcosis associated with cases of antifungal resistance of Cryptococcus spp. reported in some studies, the search for new compounds with antifungal potential becomes relevant. Thus, the objective of this study was to evaluate the inhibitory effect of phenothiazines (promethazine and chlorpromazine) on C. neoformans/C. gattii planktonic cells and biofilms. In vitro planktonic susceptibility testing was performed using the broth microdilution assay. The effect of phenothiazines was evaluated against biofilm formation and mature Cryptococcus biofilms. Biofilm morphology and ultrastructure were also evaluated by scanning electron microscopy. Promethazine and chlorpromazine showed antifungal activity against planktonic cells, with minimum inhibitory concentrations of 8-32 µg/ml and 4-16 µg/ml, respectively. As for biofilm formation, phenothiazines reduced biomass by 60% and metabolic activity by 90% at 64 µg/ml; while in mature biofilms, reductions of 85% and 90% in biomass and metabolic activity, respectively, were observed at 1024 µg/ml. Promethazine and chlorpromazine were also able to disrupt and fragment biofilms. In conclusion, promethazine and chlorpromazine have antifungal activity against planktonic cells and biofilms of Cryptococcus spp. These data show the potential of promethazine and chlorpromazine as antibiofilm drugs.

Parallel damage in mitochondria and lysosomes is an efficient way to photoinduce cell death.

Cells challenged by photosensitized oxidations face strong redox stresses and rely on autophagy to either survive or die. However, the use of macroautophagy/autophagy to improve the efficiency of photosensitizers, in terms of inducing cell death, remains unexplored. Here, we addressed the concept that a parallel damage in the membranes of mitochondria and lysosomes leads to a scenario of autophagy malfunction that can greatly improve the efficiency of the photosensitizer to cause cell death. Specific damage to these organelles was induced by irradiation of cells pretreated with 2 phenothiazinium salts, methylene blue (MB) and 1,9-dimethyl methylene blue (DMMB). At a low concentration level (10 nM), only DMMB could induce mitochondrial damage, leading to mitophagy activation, which did not progress to completion because of the parallel damage in lysosome, triggering cell death. MB-induced photodamage was perceived almost instantaneously after irradiation, in response to a massive and nonspecific oxidative stress at a higher concentration range (2 µM). We showed that the parallel damage in mitochondria and lysosomes activates and inhibits mitophagy, leading to a late and more efficient cell death, offering significant advantage (2 orders of magnitude) over photosensitizers that cause unspecific oxidative stress. We are confident that this concept can be used to develop better light-activated drugs. Abbreviations: ΔΨm: mitochondrial transmembrane inner potential; AAU: autophagy arbitrary units; ATG5, autophagy related 5; ATG7: autophagy related 7; BAF: bafilomycin A1; BSA: bovine serum albumin; CASP3: caspase 3; CF: carboxyfluorescein; CTSB: cathepsin B; CVS: crystal violet staining; DCF: dichlorofluorescein; DCFH2: 2',7'-dichlorodihydrofluorescein; DMMB: 1,9-dimethyl methylene blue; ER: endoplasmic reticulum; HaCaT: non-malignant immortal keratinocyte cell line from adult human skin; HP: hydrogen peroxide; LC3B-II: microtubule associated protein 1 light chain 3 beta-II; LMP: lysosomal membrane permeabilization; LTG: LysoTracker™ Green DND-26; LTR: LysoTracker™ Red DND-99; 3-MA: 3-methyladenine; MB: methylene blue; mtDNA: mitochondrial DNA; MitoSOX™: red mitochondrial superoxide probe; MTDR: MitoTracker™ Deep Red FM; MTO: MitoTracker™ Orange CMTMRos; MT-ND1: mitochondrially encoded NADH:ubiquinone oxidoreductase core subunit 1; MTT: methylthiazolyldiphenyl-tetrazolium bromide; 1O2: singlet oxygen; OH. hydroxil radical; PRKN/parkin: parkin RBR E3 ubiquitin protein ligase; PBS: phosphate-buffered saline; PI: propidium iodide; PDT: photodynamic therapy; PS: photosensitizer; QPCR: gene-specific quantitative PCR-based; Rh123: rhodamine 123; ROS: reactive oxygen species RTN: rotenone; SQSTM1/p62: sequestosome 1; SUVs: small unilamellar vesicles; TBS: Tris-buffered saline.

Unveiling One-Dimensional Supramolecular Structures Formed through π-π Stacking of Phenothiazines by Differential Pulse Voltammetry.

Organic-based nanomaterials can be self-assembled by strong and directional intermolecular forces such as π-π interactions. Experimental information about the stability, size, and geometry of the formed structures is very limited for species that easily aggregate, even at very low concentrations. Differential pulse voltammetry (DPV) can unveil the formation, growth, and also the stability window of ordered, one-dimensional, lamellar self-aggregates formed by supramolecular π stacking of phenothiazines at micromolar (10-6  mol L-1 ) concentrations. The self-diffusion features of the species at different concentrations are determined by DPV and used to probe the π staking process through the concept of the frictional resistance. It is observed that toluidine blue and methylene blue start to self-aggregate around 9 µmol L-1 , and that the self-aggregation process occurs by one-dimensional growth as the concentration of the phenothiazines is increased up to around 170 µmol L-1 for toluidine blue and 200 µmol L-1 for methylene blue. At higher concentrations, the aggregation process leads to structures with lower anisometry.

Synthesis and physicochemical properties of polyacrylamide nanoparticles as photosensitizer carriers.

At present, polyacrylamide nanoparticles are attractive to drug delivery. However, some physicochemical characteristics of these nanoparticles still need to be further improved in practice. Polyacrylamide nanoparticles with an average size of 80nm and a zeta potential of -30mV were synthesized and used as photosensitizer carriers. The new monobrominated derivatives and parent compounds were the photosensitizers for the photodynamic therapy loaded in the nanocarrier. The physicochemical characterization of the prepared nanoparticles, drug loading, the ability to generate singlet oxygen and chemical stability were investigated. The novel tested nanoparticles exhibited a loading percentage of between 80 and 99%, higher generation of singlet oxygen and good stability in comparison with the corresponding starting reagent. According to these results, the novel polyacrylamide nanoparticles are excellent candidates for drug vehiculization.

Enhancement of chlorpromazine antitumor activity by Pluronics F127/L81 nanostructured system against human multidrug resistant leukemia.

The development of specific tyrosine kinase inhibitors (TKIs) revolutionized the treatment of chronic myeloid leukemia (CML). However, chemoresistance of tumor cells to TKIs has already been described, and several mechanisms account for the multidrug resistance (MDR) phenotypes, including the overexpression of P-glycoprotein (P-gp). This decreases the rate of healing and complete tumor remission. Nanotechnological tools have been studied to allow advances in this field. Poloxamers (Pluronics(®)) have been proposed as drug carriers to improve therapeutic efficacy and decrease side effects, even in cancer therapy, due to their ability to inhibit P-gp. Antipsychotic phenothiazines have been described as potent cytotoxic drugs against several types of tumor cells in vitro. Here, we show that nanostructured micellar systems containing the phenothiazine derivative chlorpromazine (CPZ) potentiated the cytotoxicity of free CPZ and increased the selectivity against CML tumor cells, demonstrating the pharmacological potential of these poloxamer-based nanostructured systems containing CPZ in cancer therapy.

Binding of phenothiazines into allosteric hydrophobic pocket of human thioredoxin 1.

Thioredoxins are multifunctional oxidoreductase proteins implicated in the antioxidant cellular apparatus and oxidative stress. They are involved in several pathologies and are promising anticancer targets. Identification of noncatalytic binding sites is of great interest for designing new allosteric inhibitors of thioredoxin. In a recent work, we predicted normal mode motions of human thioredoxin 1 and identified two major putative hydrophobic binding sites. In this work we investigated noncovalent interactions of human thioredoxin 1 with three phenotiazinic drugs acting as prooxidant compounds by using molecular docking and circular dichroism spectrometry to probe ligand binding into the previously predicted allosteric hydrophobic pockets. Our in silico and CD spectrometry experiments suggested one preferred allosteric binding site involving helix 3 and adopting the best druggable conformation identified by NMA. The CD spectra showed binding of thioridazine into thioredoxin 1 and suggested partial helix unfolding, which most probably concerns helix 3. Taken together, these data support the strategy to design thioredoxin inhibitors targeting a druggable allosteric binding site.

Design, synthesis, in vitro evaluation and preliminary SAR studies of N-(2-(heteroaryloxy)propyl)phenothiazines against Rhipicephalus microplus cattle tick.

A family of 15 N-substituted phenothiazines was designed, synthesized and their acaricidal activity against Rhipicephalus microplus was determined in vitro. The synthetic methodology is simple and can be employed in multigram scale. The rationale for the structure-based design of these compounds is the potential for azines and phenothiazine to engage in π-π interactions; these fragments, joined together by a short, flexible alkoxide linker, structurally resemble phenothiazine-based cholinesterase inhibitors, while their weak basicity implies a neutral active form, rather than a cationic one, thus facilitating penetration of the cuticle of ticks. One compound displayed excellent acaricidal activity (LD50=0.58 µg/mL). Preliminary SAR analysis suggests that the activity is influenced by the presence of a weakly basic nitrogen atom, as well as the substitution pattern within the heterocycles.

Splenic congestion associated with acepromazine administration in dogs / Congestão esplênica associada à aplicação de acepromazina em cães

The effects splenic dilatation induced by acepromazine in a prospective, randomized study. Thirtythree adult mongrel dogs were divided into two groups designated as AG (acepromazine 0.05 mg/kg, i.v., n = 23) and CG (0.9 percent sodium chloride administered at a similar volume, n = 10). In both groups underwent sonographic examinations before (T0) and fifteen minutes (T15) after drug injection. The thickness spleen and splenic vein width were measured. Higher thickness was found in the AG group at T15 (2.47 cm) when compared to that at T0 (2.06 cm, p = 0.016), while the T0 (2.33 cm) and T15 (2.39 cm) measures did not differ within the CG group. Moreover, the splenic vein width was higher (p = 0.013) at T15 than at T0 in the AG group. Based on results of this study, we concluded that acepromazine, in doses of 0.05 mg/kg, promotes splenomegaly in dogs after fifteen minutes of the injection.

Foram avaliados os efeitos de dilatação esplênica induzidos pela acepromazina em estudo do tipo prospectivo e randomizado. Trinta e três cães foram distribuídos em dois grupos designados como GA (acepromazina 0,05 mg/kg, i.v., n = 23) e GC (solução de cloreto de sódio 0,9 por cento em volume semelhante ao GA, i.v., n = 10). Em ambos os grupos foi realizada ultrassonografia abdominal previamente à aplicação das substâncias (T0) e após 15 minutos (T15). A espessura do baço e a largura da veia esplênica foram mensuradas. Foi verificada maior espessura esplênica no GA no T15 (2,47 cm) quando comparado a T0 (2,06 cm, p = 0,016), enquanto no GC não houve diferença significativa, sendo T0 (2,33 cm) e T15 (2,39 cm). Ainda, a largura da veia esplênica foi maior no T15 (p = 0,013) comparado a T0no GA. Baseado nos resultados encontrados, pode-se concluir que a acepromazina na dose de 0,05 mg/kg induz a esplenomegalia em cães após 15 minutos da aplicação.

Efeitos de compostos naturais, sintéticos e da fototerapia antifúngica sobre Candida tropicalis resistente ao fluconazol / Effects of natural compounds, synthetic and herbal medicine on Candida tropicalis antifungal fluconazole-resistant

A candidíase é uma infecção oportunista provocada por diversas espécies de fungos do gênero Candida, frequentemente encontrados integrando a microbiota, da superfície cutânea, no trato gastrointestinal e cavidades mucosas do ser humano desde o seu nascimento. A incidência das infecções fúngicas sistêmicas têm aumentado consideravelmente nas últimas décadas em função do grande número de pacientes com SIDA, a grande quantidade de transplantes e condições crônicas como o câncer, a terapia prolongada com imunossupressores e o uso de agentes corticosteroides. Além disso, a exposição prolongada aos antifúngicos azólicos promove a seleção de patógenos resistentes. No presente estudo avaliou-se a atividade antifúngica do complexo Rutênio-pirocatecol (RPC) frente a um isolado clinico de Candida tropicalis resistente ao fluconazol. A metodologia empregada para os testes de susceptibilidade foi de acordo com o documento M27-A3 do National Committee for Clinical Laboratory Standards (NCCLS, 2008). Esplenócitos de camundongos Balb/c foram obtidos de forma asséptica para avaliar a citotoxicidade do composto para células de mamíferos. O estresse oxidativo promovido pelo composto foi avaliado através da reação ao ácido tiobarbitúrico (TBARS) e ensaios de fluorescência com a sonda diclorodihidrofluoresceína diacetato (DCFH2DA). O Calcofluor White foi empregado para avaliar a integridade da parede celular. A análise ultraestrutural foi realizada através da microscopia eletrônica de varredura e transmissão. Os resultados encontrados para os testes de atividade antifúngica foram analisados através do teste estatístico ANOVA e pós-teste Dunnett. Os resultados encontrados para os testes de atividade antifúngica do RPC mostraram uma Concentração Inibitória de 50% (IC50) de 20,3 μM, enquanto em esplesnócitos a concentração efetiva de 50% foi de 325 μM mostrando um índice de seletividade igual a 16...

Candidiasis is an opportunistic infection caused by several species of fungi of the genus Candida, often found is the microbiota, on the skin, gastrointestinal tract and mucous cavities of the human beings birth. The incidence of systemic fungal infections have increased considerably in recent decades due to the large number of AIDS patients, the large number of transplants and chronic conditions such as cancer, prolonged therapy promotes the selection of resistant pathogen with immunosuppressant and corticosteroid agents. Also prolonged exposure azole antifungals to make them strong candidates for patients resistance. In the present study we evaluated the antifungal activity of Ruthenium-pyrocatechol complex (RPC) against a clinical isolate of Candida tropicalis resistant to fluconazole. The methodology for susceptibility testing was in accordance with the M27-A3 document of there National Committee for Clinical Laboratory Standards (NCCLS, 2008). Splenocytes from Balb/c mice were obtained aseptically to evaluate the cytotoxicity of the compound to mammalian cells. Oxidative stress caused by the compound was assessed by reaction to thiobarbituric acid (TBARS) and fluorescence assays with the probe diclorodihidrofluoresceína diacetate (DCFH2DA). The Calcofluor White was used to evaluate the integrity of the cell wall. The ultrastructural analysis was performed by scanning and transmission electron microscopy. The results for the antifungal activity tests were analyzed using ANOVA and pos-test Dunnett test statistic. The results for the tests of antifungal activity of the RPC showed a 50% inhibitory concentration (IC50) of 20.3 μM while in splenocytes the 50% effective concentration was 325 μM showing a selectivity index of 16...

Splenic congestion associated with acepromazine administration in dogs / Congestão esplênica associada à aplicação de acepromazina em cães

The effects splenic dilatation induced by acepromazine in a prospective, randomized study. Thirtythree adult mongrel dogs were divided into two groups designated as AG (acepromazine 0.05 mg/kg, i.v., n = 23) and CG (0.9% sodium chloride administered at a similar volume, n = 10). In both groups underwent sonographic examinations before (T0) and fifteen minutes (T15) after drug injection. The thickness spleen and splenic vein width were measured. Higher thickness was found in the AG group at T15 (2.47 cm) when compared to that at T0 (2.06 cm, p = 0.016), while the T0 (2.33 cm) and T15 (2.39 cm) measures did not differ within the CG group. Moreover, the splenic vein width was higher (p = 0.013) at T15 than at T0 in the AG group. Based on results of this study, we concluded that acepromazine, in doses of 0.05 mg/kg, promotes splenomegaly in dogs after fifteen minutes of the injection.(AU)

Foram avaliados os efeitos de dilatação esplênica induzidos pela acepromazina em estudo do tipo prospectivo e randomizado. Trinta e três cães foram distribuídos em dois grupos designados como GA (acepromazina 0,05 mg/kg, i.v., n = 23) e GC (solução de cloreto de sódio 0,9% em volume semelhante ao GA, i.v., n = 10). Em ambos os grupos foi realizada ultrassonografia abdominal previamente à aplicação das substâncias (T0) e após 15 minutos (T15). A espessura do baço e a largura da veia esplênica foram mensuradas. Foi verificada maior espessura esplênica no GA no T15 (2,47 cm) quando comparado a T0 (2,06 cm, p = 0,016), enquanto no GC não houve diferença significativa, sendo T0 (2,33 cm) e T15 (2,39 cm). Ainda, a largura da veia esplênica foi maior no T15 (p = 0,013) comparado a T0no GA. Baseado nos resultados encontrados, pode-se concluir que a acepromazina na dose de 0,05 mg/kg induz a esplenomegalia em cães após 15 minutos da aplicação.(AU)

Comparison of the sedative effects of morphine, meperidine or fentanyl, in combination with acepromazine, in dogs / Comparação dos efeitos sedativos da morfina, meperidina ou fentanil, associados à acepromazina, em cães

This study aimed to compare the sedative effects of morphine, meperidine and fentanyl, in combination with acepromazine (ACP) and their effects on physiologic values in dogs. Six healthy beagle dogs were randomly assigned to four treatments with 7-day washout intervals. In three treatments, ACP (0.05mg kg-1) was administered and 20 minutes later, the dogs received administration of 0.5mg kg-1 of morphine (ACPMOR), 5mg kg-1 of meperidine (ACPMEP) or 5µg kg-1 of fentanyl (ACPFEN). In treatment ACP HD MOR, 0.1mg kg-1 of ACP was administered in combination with 0.5mg kg-1 of morphine. All drugs were administered intravenously. Sedation scores were evaluated by a numeric descriptive scale (NDS: 0-3) and a simple numeric scale (SNS: 0-10). All variables were evaluated for 120 minutes. The administration of ACP caused mild to moderate sedation. Sedation was improved in all treatments after opioid administration, but significant differences were detected only in ACPMOR and ACP HD MOR. More dogs presented intense sedation (NDS=3.0) after administration of morphine (3/6 and 4/6 dogs in ACPMOR and ACP HD MOR versus 1/6 in other treatments). Duration of sedation was longer in ACPMOR and ACP HD MOR. Mild to moderate decreases in blood pressure, respiratory rate and temperature were observed in all treatments but decreased HR was observed only in ACPMOR and ACP HD MOR. No significant differences were observed in the aforementioned variables when twice the dose of ACP was used (treatment ACP HD MOR). Under the conditions of this study, administration of morphine, in combination with ACP, results in greater and longer sedation than meperidine and fentanyl. Increasing the dose of ACP, in combination with morphine, does not improve the degree of sedation. All combinations used were considered to be safe for healthy dogs.

O presente estudo objetivou comparar o efeito sedativo da morfina, meperidina e fentanil associados à acepromazina (ACP) e seus efeitos sobre as variáveis fisiológicas de cães. Seis cães Beagle hígidos foram aleatoriamente submetidos a quatro tratamentos com intervalo de 7 dias. Em três tratamentos, foi administrada ACP (0,05mg kg-1) e, após 20 minutos, 0,5mg kg-1 de morfina (ACPMOR), 5mg kg-1 de meperidina (ACPMEP) ou 5µg kg-1 de fentanil (ACPFEN). No tratamento ACP DA MOR, a dose de 0,1mg kg-1 de ACP foi associada a 0,5mg kg-1 de morfina. Todos os fármacos foram administrados pela via IV. Escores de sedação foram avaliados pela escala numérica descritiva (END: 0-3) e escala numérica simples (ENS: 0-10). Todas as variáveis foram avaliadas durante 120 minutos. A administração da ACP causou sedação leve à moderada. A sedação foi intensificada em todos os tratamentos após a administração do opioide, mas diferença significativa foi observada somente em ACPMOR e ACP DA MOR. Um número maior de cães apresentou sedação intensa (END=3,0) após a administração da morfina (3/6 e 4/6 cães em ACPMOR e ACP DA MOR versus 1/6 nos demais tratamentos). A duração do efeito sedativo foi mais longa em ACPMOR e ACP DA MOR. Houve redução leve a moderada na pressão arterial, frequência respiratória e temperatura em todos os tratamentos e redução significativa da frequência cardíaca somente nos tratamentos ACPMOR e ACP DA MOR. Não houve diferenças significativas nas variáveis estudadas quando o dobro da dose de ACP foi utilizada (tratamento ACP DA MOR). Nas condições deste estudo, a administração da morfina, em associação à ACP, resulta em sedação de maior intensidade e duração do que a meperidina e o fentanil. O aumento na dose de ACP, em associação à morfina, não intensifica o grau de sedação. Todas as associações foram consideradas seguras para cães hígidos.

Influence of acepromazine on the cardiovascular actions of dobutamine in isoflurane-anesthetized horses / Influência da acepromazina sobre os efeitos cardiovasculares da dobutamina em cavalos anestesiados com isofluorano

The influence of acepromazine (ACP) on the effectiveness of dobutamine (DBT) in increasing blood pressure during isoflurane (ISO) anesthesia was evaluated in six horses. On separate occasions, the horses were randomly assigned to receive NaCl 0.9 percent (Control), ACP 0.025mg kg-1 and ACP 0.05mg kg-1. The experimental treatment was administered prior to induction of anesthesia. Maintenance of anesthesia was performed under conditions of normocapnia with ISO in oxygen. Dobutamine was administered at progressively increasing infusion rates until mean arterial pressure (MAP) reached 70mmHg or until a maximum infusion rate of 5.0µg kg-1 min-1. Compared with baseline, DBT increased heart rate, systolic, diastolic and mean blood pressures in all treatments. However, these variables did not differ among treatments. The target MAP (70mmHg) was not reached in 2/6, 2/5 and 0/6 horses in the Control, ACP0.025 and ACP0.05 treatments, respectively. The mean dose of DBT to achieve target MAP was 3.5±1.8, 3.7±1.6 and 2.7±1.4µg kg-1 min-1 in the Control, ACP0.025 and ACP0.05 treatments, respectively (P>0.05). Under the conditions of this study, premedication with ACP does not interfere with the effectiveness of DBT in increasing blood pressure in horses anesthetized with ISO.

A influência da acepromazina (ACP) sobre a capacidade da dobutamina (DBT) em elevar a pressão arterial durante a anestesia com isofluorano (ISO) foi avaliada em seis equinos. Em ocasiões diferentes, os animais receberam aleatoriamente NaCl 0,9 por cento (Controle), ACP 0,025mg kg-1 e ACP 0,05mg kg-1. O tratamento experimental foi administrado previamente à indução da anestesia. A manutenção da anestesia foi realizada em condições de normocapnia com ISO em oxigênio. A administração de DBT foi iniciada em doses progressivamente crescentes até que o valor de pressão arterial média (PAM) atingisse 70mmHg ou até a dose máxima de 5,0µg kg-1 min-1. Comparado ao basal, a administração da DBT resultou em elevação na frequência cardíaca e pressões arteriais sistólica, diastólica e média em todos os tratamentos. Porém, não houve diferença entre os tratamentos nessas variáveis. A PAM alvo (70mmHg) não foi atingida em 2/6, 2/5 e 0/6 animais dos tratamentos Controle, ACP0.025 e ACP0.05, respectivamente. A dose média de DBT para a PAM alvo foi de 3,5±1,8; 3,7±1,6 e 2,7±1,4µg kg-1 min-1 no Controle, ACP0.025 e ACP0.05, respectivamente (P>0,05). Nas condições deste estudo, o pré-tratamento com ACP não interfere na eficácia da DBT em elevar a pressão arterial de cavalos anestesiados com ISO.

Comparison of the sedative effects of morphine, meperidine or fentanyl, in combination with acepromazine, in dogs

This study aimed to compare the sedative effects of morphine, meperidine and fentanyl, in combination with acepromazine (ACP) and their effects on physiologic values in dogs. Six healthy beagle dogs were randomly assigned to four treatments with 7-day washout intervals. In three treatments, ACP (0.05mg kg-1) was administered and 20 minutes later, the dogs received administration of 0.5mg kg-1 of morphine (ACPMOR), 5mg kg-1 of meperidine (ACPMEP) or 5µg kg-1 of fentanyl (ACPFEN). In treatment ACP HD MOR, 0.1mg kg-1 of ACP was administered in combination with 0.5mg kg-1 of morphine. All drugs were administered intravenously. Sedation scores were evaluated by a numeric descriptive scale (NDS: 0-3) and a simple numeric scale (SNS: 0-10). All variables were evaluated for 120 minutes. The administration of ACP caused mild to moderate sedation. Sedation was improved in all treatments after opioid administration, but significant differences were detected only in ACPMOR and ACP HD MOR. More dogs presented intense sedation (NDS=3.0) after administration of morphine (3/6 and 4/6 dogs in ACPMOR and ACP HD MOR versus 1/6 in other treatments). Duration of sedation was longer in ACPMOR and ACP HD MOR. Mild to moderate decreases in blood pressure, respiratory rate and temperature were observed in all treatments but decreased HR was observed only in ACPMOR and ACP HD MOR. No significant differences were observed in the aforementioned variables when twice the dose of ACP was used (treatment ACP HD MOR). Under the conditions of this study, administration of morphine, in combination with ACP, results in greater and longer sedation than meperidine and fentanyl. Increasing the dose of ACP, in combination with morphine, does not improve the degree of sedation. All combinations used were considered to be safe for healthy dogs.

O presente estudo objetivou comparar o efeito sedativo da morfina, meperidina e fentanil associados à acepromazina (ACP) e seus efeitos sobre as variáveis fisiológicas de cães. Seis cães Beagle hígidos foram aleatoriamente submetidos a quatro tratamentos com intervalo de 7 dias. Em três tratamentos, foi administrada ACP (0,05mg kg-1) e, após 20 minutos, 0,5mg kg-1 de morfina (ACPMOR), 5mg kg-1 de meperidina (ACPMEP) ou 5µg kg-1 de fentanil (ACPFEN). No tratamento ACP DA MOR, a dose de 0,1mg kg-1 de ACP foi associada a 0,5mg kg-1 de morfina. Todos os fármacos foram administrados pela via IV. Escores de sedação foram avaliados pela escala numérica descritiva (END: 0-3) e escala numérica simples (ENS: 0-10). Todas as variáveis foram avaliadas durante 120 minutos. A administração da ACP causou sedação leve à moderada. A sedação foi intensificada em todos os tratamentos após a administração do opioide, mas diferença significativa foi observada somente em ACPMOR e ACP DA MOR. Um número maior de cães apresentou sedação intensa (END=3,0) após a administração da morfina (3/6 e 4/6 cães em ACPMOR e ACP DA MOR versus 1/6 nos demais tratamentos). A duração do efeito sedativo foi mais longa em ACPMOR e ACP DA MOR. Houve redução leve a moderada na pressão arterial, frequência respiratória e temperatura em todos os tratamentos e redução significativa da frequência cardíaca somente nos tratamentos ACPMOR e ACP DA MOR. Não houve diferenças significativas nas variáveis estudadas quando o dobro da dose de ACP foi utilizada (tratamento ACP DA MOR). Nas condições deste estudo, a administração da morfina, em associação à ACP, resulta em sedação de maior intensidade e duração do que a meperidina e o fentanil. O aumento na dose de ACP, em associação à morfina, não intensifica o grau de sedação. Todas as associações foram consideradas seguras para cães hígidos.

Influence of acepromazine on the cardiovascular actions of dobutamine in isoflurane-anesthetized horses

The influence of acepromazine (ACP) on the effectiveness of dobutamine (DBT) in increasing blood pressure during isoflurane (ISO) anesthesia was evaluated in six horses. On separate occasions, the horses were randomly assigned to receive NaCl 0.9% (Control), ACP 0.025mg kg-1 and ACP 0.05mg kg-1. The experimental treatment was administered prior to induction of anesthesia. Maintenance of anesthesia was performed under conditions of normocapnia with ISO in oxygen. Dobutamine was administered at progressively increasing infusion rates until mean arterial pressure (MAP) reached 70mmHg or until a maximum infusion rate of 5.0µg kg-1 min-1. Compared with baseline, DBT increased heart rate, systolic, diastolic and mean blood pressures in all treatments. However, these variables did not differ among treatments. The target MAP (70mmHg) was not reached in 2/6, 2/5 and 0/6 horses in the Control, ACP0.025 and ACP0.05 treatments, respectively. The mean dose of DBT to achieve target MAP was 3.5±1.8, 3.7±1.6 and 2.7±1.4µg kg-1 min-1 in the Control, ACP0.025 and ACP0.05 treatments, respectively (P>0.05). Under the conditions of this study, premedication with ACP does not interfere with the effectiveness of DBT in increasing blood pressure in horses anesthetized with ISO.

A influência da acepromazina (ACP) sobre a capacidade da dobutamina (DBT) em elevar a pressão arterial durante a anestesia com isofluorano (ISO) foi avaliada em seis equinos. Em ocasiões diferentes, os animais receberam aleatoriamente NaCl 0,9% (Controle), ACP 0,025mg kg-1 e ACP 0,05mg kg-1. O tratamento experimental foi administrado previamente à indução da anestesia. A manutenção da anestesia foi realizada em condições de normocapnia com ISO em oxigênio. A administração de DBT foi iniciada em doses progressivamente crescentes até que o valor de pressão arterial média (PAM) atingisse 70mmHg ou até a dose máxima de 5,0µg kg-1 min-1. Comparado ao basal, a administração da DBT resultou em elevação na frequência cardíaca e pressões arteriais sistólica, diastólica e média em todos os tratamentos. Porém, não houve diferença entre os tratamentos nessas variáveis. A PAM alvo (70mmHg) não foi atingida em 2/6, 2/5 e 0/6 animais dos tratamentos Controle, ACP0.025 e ACP0.05, respectivamente. A dose média de DBT para a PAM alvo foi de 3,5±1,8; 3,7±1,6 e 2,7±1,4µg kg-1 min-1 no Controle, ACP0.025 e ACP0.05, respectivamente (P>0,05). Nas condições deste estudo, o pré-tratamento com ACP não interfere na eficácia da DBT em elevar a pressão arterial de cavalos anestesiados com ISO.

Comparison of the sedative effects of morphine, meperidine or fentanyl, in combination with acepromazine, in dogs

This study aimed to compare the sedative effects of morphine, meperidine and fentanyl, in combination with acepromazine (ACP) and their effects on physiologic values in dogs. Six healthy beagle dogs were randomly assigned to four treatments with 7-day washout intervals. In three treatments, ACP (0.05mg kg-1) was administered and 20 minutes later, the dogs received administration of 0.5mg kg-1 of morphine (ACPMOR), 5mg kg-1 of meperidine (ACPMEP) or 5µg kg-1 of fentanyl (ACPFEN). In treatment ACP HD MOR, 0.1mg kg-1 of ACP was administered in combination with 0.5mg kg-1 of morphine. All drugs were administered intravenously. Sedation scores were evaluated by a numeric descriptive scale (NDS: 0-3) and a simple numeric scale (SNS: 0-10). All variables were evaluated for 120 minutes. The administration of ACP caused mild to moderate sedation. Sedation was improved in all treatments after opioid administration, but significant differences were detected only in ACPMOR and ACP HD MOR. More dogs presented intense sedation (NDS=3.0) after administration of morphine (3/6 and 4/6 dogs in ACPMOR and ACP HD MOR versus 1/6 in other treatments). Duration of sedation was longer in ACPMOR and ACP HD MOR. Mild to moderate decreases in blood pressure, respiratory rate and temperature were observed in all treatments but decreased HR was observed only in ACPMOR and ACP HD MOR. No significant differences were observed in the aforementioned variables when twice the dose of ACP was used (treatment ACP HD MOR). Under the conditions of this study, administration of morphine, in combination with ACP, results in greater and longer sedation than meperidine and fentanyl. Increasing the dose of ACP, in combination with morphine, does not improve the degree of sedation. All combinations used were considered to be safe for healthy dogs.

O presente estudo objetivou comparar o efeito sedativo da morfina, meperidina e fentanil associados à acepromazina (ACP) e seus efeitos sobre as variáveis fisiológicas de cães. Seis cães Beagle hígidos foram aleatoriamente submetidos a quatro tratamentos com intervalo de 7 dias. Em três tratamentos, foi administrada ACP (0,05mg kg-1) e, após 20 minutos, 0,5mg kg-1 de morfina (ACPMOR), 5mg kg-1 de meperidina (ACPMEP) ou 5µg kg-1 de fentanil (ACPFEN). No tratamento ACP DA MOR, a dose de 0,1mg kg-1 de ACP foi associada a 0,5mg kg-1 de morfina. Todos os fármacos foram administrados pela via IV. Escores de sedação foram avaliados pela escala numérica descritiva (END: 0-3) e escala numérica simples (ENS: 0-10). Todas as variáveis foram avaliadas durante 120 minutos. A administração da ACP causou sedação leve à moderada. A sedação foi intensificada em todos os tratamentos após a administração do opioide, mas diferença significativa foi observada somente em ACPMOR e ACP DA MOR. Um número maior de cães apresentou sedação intensa (END=3,0) após a administração da morfina (3/6 e 4/6 cães em ACPMOR e ACP DA MOR versus 1/6 nos demais tratamentos). A duração do efeito sedativo foi mais longa em ACPMOR e ACP DA MOR. Houve redução leve a moderada na pressão arterial, frequência respiratória e temperatura em todos os tratamentos e redução significativa da frequência cardíaca somente nos tratamentos ACPMOR e ACP DA MOR. Não houve diferenças significativas nas variáveis estudadas quando o dobro da dose de ACP foi utilizada (tratamento ACP DA MOR). Nas condições deste estudo, a administração da morfina, em associação à ACP, resulta em sedação de maior intensidade e duração do que a meperidina e o fentanil. O aumento na dose de ACP, em associação à morfina, não intensifica o grau de sedação. Todas as associações foram consideradas seguras para cães hígidos.