Activation of M1 muscarinic acetylcholine receptors by proline-rich oligopeptide 7a (Bothrops jararaca snake venom rescues oxidative stress-induced neurotoxicity in PC12 cells.

Background: The bioactive peptides derived from snake venoms of the Viperidae family species have been promising as therapeutic candidates for neuroprotection due to their ability to prevent neuronal cell loss, injury, and death. Therefore, this study aimed to evaluate the cytoprotective effects of a synthetic proline-rich oligopeptide 7a (PRO-7a;

Activation of M1 muscarinic acetylcholine receptors by proline-rich oligopeptide 7a (

Background: The bioactive peptides derived from snake venoms of the Viperidae family species have been promising as therapeutic candidates for neuroprotection due to their ability to prevent neuronal cell loss, injury, and death. Therefore, this study aimed to evaluate the cytoprotective effects of a synthetic proline-rich oligopeptide 7a (PRO-7a; <EDGPIPP) from Bothrops jararaca snake, on oxidative stress-induced toxicity in neuronal PC12 cells and astrocyte-like C6 cells. Methods: Both cells were pre-treated for four hours with different concentrations of PRO-7a, submitted to H2O2-induced damage for 20 h, and then the oxidative stress markers were analyzed. Also, two independent neuroprotective mechanisms were investigated: a) L-arginine metabolite generation via argininosuccinate synthetase (AsS) activity regulation to produce agmatine or polyamines with neuroprotective properties; b) M1 mAChR receptor subtype activation pathway to reduce oxidative stress and neuron injury. Results: PRO-7a was not cytoprotective in C6 cells, but potentiated the H2O2-induced damage to cell integrity at a concentration lower than 0.38 μM. However, PRO-7a at 1.56 µM, on the other hand, modified H2O2-induced toxicity in PC12 cells by restoring cell integrity, mitochondrial metabolism, ROS generation, and arginase indirect activity. The α-Methyl-DL-aspartic acid (MDLA) and L-NΩ-Nitroarginine methyl ester (L-Name), specific inhibitors of AsS and nitric oxide synthase (NOS), which catalyzes the synthesis of polyamines and NO from L-arginine, did not suppress PRO-7a-mediated cytoprotection against oxidative stress. It suggested that its mechanism is independent of the production of L-arginine metabolites with neuroprotective properties by increased AsS activity. On the other hand, the neuroprotective effect of PRO-7a was blocked in the presence of dicyclomine hydrochloride (DCH), an M1 mAChR antagonist. Conclusions: For the first time, this work provides evidence that PRO-7a-induced neuroprotection seems to be mediated through M1 mAChR activation in PC12 cells, which reduces oxidative stress independently of AsS activity and L-arginine bioavailability.(AU)

Prenatal exposition to haloperidol: A preclinical narrative review.

Pre-existing maternal mental disorders may affect the early interactions between mother and baby, impacting the child's psychoemotional development. The typical antipsychotic haloperidol can be used during pregnancy, even with some restrictions. Its prescription is not limited to psychotic disorders, but also to other psychiatric conditions of high incidence and prevalence in the woman's fertile period. The present review focused on the preclinical available data regarding the biological and behavioral implications of embryonic exposure to haloperidol. The understanding of the effects of psychotropic drugs during neurodevelopment is important for its clinical aspect since there is limited evidence regarding the risks of antipsychotic drug treatment in pregnant women and their children. Moreover, a better comprehension of the mechanistic events that can be affected by antipsychotic treatment during the critical period of neurodevelopment may offer insights into the pathophysiology of neurodevelopmental disorders. The findings presented in this review converge to the existence of several risks associated with prenatal exposure to such medication and emphasize the need for further studies regarding its dimensions.

Extrapyramidal Side Effects with Chronic Atypical Antipsychotic Can Be Predicted by Labeling Pattern of FosB and phosphoThr34-DARPP-32 in Nucleus Accumbens.

Extrapyramidal side effects (EPS) can be induced by neuroleptics that regulate the expression of transcription factor FosB and dopaminergic mediator DARPP-32 in the striatum. However, the long-term neurobiological changes in striatal projection neurons resulting from a cumulative dosage of typical and atypical antipsychotics are poorly understood. The present study aimed to determine the differential and long-lasting changes in FosB distribution and DARPP-32 phosphorylation in the striatum and nucleus accumbens (NAc) associated with chronic antipsychotic-induced EPS. Male C57Bl/6J mice received daily injections of Olanzapine (Olz, 15 mg/kg), Clozapine (Clz, 20 mg/kg), or Haloperidol (Hal, 1 mg/kg), for a period of 11 weeks with a 4-day withdrawal period before the last dosage. Catalepsy for detection of EPS, along with open-field and rotarod tests, were assessed as behavioral correlates of motor responses. Additionally, FosB and phosphorylated-DARPP-32 immunohistochemistry were examined in striatal regions after treatment. All antipsychotics produced catalepsy and reduced open-field exploration, such as impaired rota-rod performance after Olz and Hal. The washout period was critical for Clz-induced side effects reduction. Both Olz and Clz increased FosB in NAc Shell-region, and phosphoThr34-DARPP-32 in NAc. Only Clz reduced phosphoThr75-DARPP-32 in the dorsal striatum and showed FosB/phosphoThr34-Darpp-32-ir in the NAc Core region. This study provides evidence that atypical antipsychotics such as Olz and Clz also give rise to EPS effects frequently associated with a cumulative dosage of typical neuroleptics such as Hal. Nevertheless, FosB/phosphoThr34-Darpp-32-ir in the NAc Core region is associated with hypokinetic movements inhibition.

Peptide fraction from B. jararaca snake venom protects against oxidative stress-induced changes in neuronal PC12 cell but not in astrocyte-like C6 cell.

Venom-derived proteins and peptides have prevented neuronal cell loss, damage, and death in the study of neurodegenerative disorders. The cytoprotective effects of the peptide fraction (PF) from Bothrops jararaca snake venom were evaluated against oxidative stress changes in neuronal PC12 cells and astrocyte-like C6 cells. PC12 and C6 cells were pre-treated for 4 h with different concentrations of PF, and then H2O2 was added (0.5 mM in PC12 cells; 0.4 mM in C6 cells) and incubated for 20 h more. In PC12 cells, PF at 0.78 µg mL-1 increased viability (113.6 ± 6.3%) and metabolism (96.3 ± 10.3%) cell against H2O2-induced neurotoxicity (75.6 ± 5.8%; 66.5 ± 3.3%, respectively), reducing oxidative stress markers such as ROS generation, NO production, and arginase indirect activity through urea synthesis. Despite that, PF showed no cytoprotective effects in C6 cells, but potentiated the H2O2-induced damage at a concentration lower than 0.07 µg mL-1. Furthermore, the role of metabolites derived from L-arginine metabolism was verified in PF-mediated neuroprotection in PC12 cells, using specific inhibitors of two of the key enzymes in the L-arginine metabolic pathway: the α-Methyl-DL-aspartic acid (MDLA) to argininosuccinate synthetase (AsS), responsible for the recycling of L-citrulline to L-arginine; and, L-NΩ-Nitroarginine methyl ester (L-Name) to nitric oxide synthase (NOS), which catalyzes the synthesis of NO from L-arginine. The inhibition of AsS and NOS suppressed PF-mediated cytoprotection against oxidative stress, indicating that its mechanism is dependent on the production pathway of L-arginine metabolites such as NO and, more importantly, polyamines from ornithine metabolism, which are involved in the neuroprotection mechanism described in the literature. Overall, this work provides novel opportunities for evaluating whether the neuroprotective properties of PF shown in particular neuronal cells are sustained and for exploring potential drug development pathways for the treatment of neurodegenerative diseases.

Retinal organoids from human-induced pluripotent stem cells: From studying retinal dystrophies to early diagnosis of Alzheimer's and Parkinson's disease.

Human-induced pluripotent stem cells (hiPSCs) have provided new methods to study neurodegenerative diseases. In addition to their wide application in neuronal disorders, hiPSCs technology can also encompass specific conditions, such as inherited retinal dystrophies. The possibility of evaluating alterations related to retinal disorders in 3D organoids increases the truthfulness of in vitro models. Moreover, both Alzheimer's (AD) and Parkinson's disease (PD) have been described as causing early retinal alterations, generating beta-amyloid protein accumulation, or affecting dopaminergic amacrine cells. This review addresses recent advances and future perspectives obtained from in vitro modeling of retinal diseases, focusing on retinitis pigmentosa (RP). Additionally, we depicted the possibility of evaluating changes related to AD and PD in retinal organoids obtained from potential patients long before the onset of the disease, constituting a valuable tool in early diagnosis. With this, we pointed out prospects in the study of retinal dystrophies and early diagnosis of AD and PD.

Cross-tolerance between nitric oxide synthase inhibition and atypical antipsychotics modify nicotinamide-adenine-dinucleotide phosphate-diaphorase activity in mouse lateral striatum.

Previous research indicates that the subchronic administration of NG-nitro-L-arginine (L-NOARG) produces tolerance to haloperidol-induced catalepsy in Swiss mice. The present study aimed to further investigate whether intermittent subchronic systemic administration of L-NOARG induces tolerance to the cataleptic effects of haloperidol as well as olanzapine or clozapine (Clz) in C57Bl mice after subchronic administration for 5 consecutive days. Striatal FosB protein expression was measured in an attempt to gain further insights into striatal mechanisms in antipsychotic-induced extrapyramidal symptoms side effects. An nicotinamide-adenine-dinucleotide phosphate-diaphorase histochemical reaction was also used to investigate whether tolerance could induce changes in the number of nitric oxide synthase-active neurons. Subchronic administration of all antipsychotics produced catalepsy, but cross-tolerance was observed only between L-NOARG (15 mg/kg, intraperitoneally) and Clz (20 mg/kg, intraperitoneally). This cross-tolerance effect was accompanied by decreased FosB protein expression in the dorsal striatum and the nucleus accumbens shell region, and reduced icotinamide-adenine-dinucleotide phosphate-diaphorase activity in the dorsal and ventral lateral striatum. Overall, these results suggest that interference with the formation of nitric oxide, mainly in the dorsal and ventral lateral-striatal regions, appears to improve the cataleptic effects induced by antipsychotics acting as antagonists of low-affinity dopamine D2 receptor, such as Clz.

Neuropéptidos en el encéfalo humano / Neuropeptides in the human brain

Resumen: los estudios en el encéfalo humano se han realizado con el fin de responder a varias preguntas de carácter científico relacionados con la neuroanatomía, neurofisiología, neurofarmacología,la neurología y la conducta. El encéfalo es el órgano en el que se encuentra la regulación de los reflejos y los mecanismos inconscientes como la transmisión del dolor, los cardiovasculares, los respiratorios, entre otros. Estos mecanismos están mediados por sustancias químicas tales como los neuropéptidos, que son cadenas cortas de aminoácidos que se han encontrado ampliamente distribuidos en el sistema nervioso central y periférico, además de ejercer acciones fisiológicas actuando como neurotransmisores, neuromoduladores (acciones paracrinas y autocrinas) y neurohormonas.En los últimos treinta años se ha incrementado el conocimiento sobre la distribución y función de los neuropéptidos en el sistema nervioso central de mamíferos (ratas, gatos, perros, alpacas, primates y humanos). Así, el objetivo de esta revisión se dirige a describir los datos más relevantes disponibles sobre los neuropéptidos en el encéfalo humano. Para ello se revisan aspectosimportantes de los neuropéptidos en el encéfalo humano como: a) La distribución, b) Las relaciones anatómicas, c) Las funciones fisiológicas, d) La coexistencia, y e) Las investigaciones futuras a realizar.

Abstract: the human brain has been used in laboratory as an experimental model in order to answer several scientific questions related to neuroanatomy, neurophysiology, neuropharmacology, neurology and behavior. The brain is the organ in which the regulation of reflexes and ®unconscious¼ mechanisms(transmission of pain, cardiovascular, respiratory, etc.) are carried out. These mechanisms are mediated by chemicals such as neuropeptides, which are shorter chains of amino acids that have been showed widely distributed in the central and peripheral nervous system and to exert physiologicalactions acting as neurotransmitters, neuromodulators (paracrine action and autocrine) and neurohormones.In the last thirty years, it has increased the knowledge on the distribution and function of neuropeptides in the central nervous system of mammals (rats, cats, dogs, alpaca, primates, and humans). Thus, the aim of this paper is to describe the most relevant information available about neuropeptides in the human brain. To do so will raise issues about neuropeptides in the human brain as: a) The distribution; b) The anatomical relationship; c) The physiological functions; d) The coexistence;and e) The related future research to make.

Nitric Oxide Synthase Inhibitor Improves De Novo and Long-Term l-DOPA-Induced Dyskinesia in Hemiparkinsonian Rats.

Inhibitors of neuronal and endothelial nitric oxide synthase decrease l-3,4-dihidroxifenilalanine (l-DOPA)-induced dyskinesias in rodents. The mechanism of nitric oxide inhibitor action is unknown. The aims of the present study were to investigate the decrease of l-DOPA-induced abnormal involuntary movements (AIMs) in 6-hydroxydopamine (6-OHDA)-lesioned rats by nitric oxide inhibitors following either acute or chronic treatment. The primary findings of this study were that NG-nitro-l-Arginine, an inhibitor of endothelial and neuronal nitric oxide synthase, attenuated AIMs induced by chronic and acute l-DOPA. In contrast, rotational behavior was attenuated only after chronic l-DOPA. The 6-OHDA lesion and the l-DOPA treatment induced a bilateral increase (1.5 times) in the neuronal nitric oxide synthase (nNOS) protein and nNOS mRNA in the striatum and in the frontal cortex. There was a parallel increase, bilaterally, of the FosB/ΔFosB, primarily in the ipsilateral striatum. The exception was in the contralateral striatum and the ipsilateral frontal cortex, where chronic l-DOPA treatment induced an increase of approximately 10 times the nNOS mRNA. Our results provided further evidence of an anti-dyskinetic effect of NOS inhibitor. The effect appeared under l-DOPA acute and chronic treatment. The l-DOPA treatment also revealed an over-expression of the neuronal NOS in the frontal cortex and striatum. Our results corroborated findings that l-DOPA-induced rotation differs between acute and chronic treatment. The effect of the NOS inhibitor conceivably relied on the l-DOPA structural modifications in the Parkinsonian brain. Taken together, these data provided a rationale for further evaluation of NOS inhibitors in the treatment of l-DOPA-induced dyskinesia.

Staphylococcus aureus resistentes a meticilina (SARM) positivos para PVL aislados en individuos sanos de Montería-Córdoba / PVL positive methicillin-resistant Staphylococcus aureus (MRSAs) strains isolated from healthy individuals in Montería, Córdoba / Staphylococcus aureus resistente à meticilina (SARM) positivos para PVL isolados em indivíduos saudáveis de "Montería, Córdoba"

Objetivo. Estudiar cepas asociadas a la comunidad de SARM y productoras de PVL en individuos sanos de la ciudad de Montería. Materiales y métodos. Estudio descriptivo, prospectivo de corte transversal, a partir de un total de 253 muestras obtenidas de hisopados faríngeos en tres comunidades: 91 internos de la cárcel de Montería (19-58 años), 100 estudiantes adultos jóvenes de la Universidad de Córdoba (17-30 años) y 62 niños en edad escolar (4-9 años) del Colegio de la Universidad de Córdoba. Los individuos participantes no estuvieron hospitalizados en los últimos meses, ni recibieron tratamiento antimicrobiano y no presentaron signos y/o síntomas clínicos. Los aislamientos fueron identificados por pruebas convencionales microbiológicas y se determinó la susceptibilidad antimicrobiana para los diferentes antibióticos a través de MicroScan™ combo 1A (SIEMENS). Para la detección de los genes nuc, mecA y PVL se utilizaron los protocolos de Brakstad et al (5), Oliveira et al (6) y Gerard et al (7) respectivamente. Resultados. De las 253 muestras analizadas, 62 (24,5%) resultaron positivas para S. aureus, de éstas 4 (6,45%) fueron resistentes a meticilina, de las cuales 2 (25%) resultaron PVL positivas; 58 (93,54%) fueron sensibles y 6 (75%) positivas para PVL. Conclusiones. Los resultados obtenidos demuestran la colonización por SARM-AC en individuos sanos, la colonización fue mayor en la población infantil y adultos jóvenes.

Objective. To study SARM and PVL producing strains in healthy individuals of Montería city. Materials and methods. This was a descriptive, prospective and transversal study. A total of 253 samples from pharyngeal swabs in three communities were studied: 91 prisoners of the jail of Montería (19-58 years old), 100 young adult students of the University of Cordoba (17-30 years old) and 62 children in school age (4-9 years old) of the primary school of the University of Cordoba. Individuals analyzed had not been hospitalized, had not received any antimicrobial treatment and did not show any clinical signs or symptoms in the last months. The isolates were identified by conventional microbiological tests and the antimicrobial susceptibility was determined for different antibiotics with MicroScan™ kit 1A (SIEMENS). For the detection of the nuc, mecA and PVL genes, we followed the protocols of Brakstad et al., Oliveira et al. and Gerard et al. respectively. Results. Of the 253 analyzed samples, 62 (24.5%) were positive for S. aureus, out of those 4 (6.45%) were resistant to methicillin and 2 (25%) of them were PVL positive; 58 (93.54%) were sensitive to methicillin and 6 (75%) positive for PVL. Conclusions. Results obtained in this study show the colonization by SARM-AC of healthy individuals. Colonization was higher in young adults and children in school-age.

Objetivo. Estudar cepas associada à comunidade de SARM e produtoras de PVL em indivíduos saudáveis da cidade de Monteria. Materiais e métodos. Estudo descriptivo, prospectivo de corte transversal, de um total de 253 amostras obtidas em esfregaços faríngeos em três comunidades: 91 reclusos em Monteria (19-58 anos), 100 alunos adultos jovens da "Universidad de Córdoba" (17 - 30 anos) e 62 crianças em idade escolar (4-9 anos) do "Colégio de la Universidad de Córdoba". Os indivíduos envolvidos não foram internados nos últimos meses, ou receberam tratamento antimicrobiano e não tinham sinais e / ou sintomas clínicos. Os isolados foram identificados por testes microbiológicos convencionais e se determinou a susceptibilidade antimicrobiana aos diferentes antibióticos através de MicroScan™ combo 1A (SIEMENS). Para a detecção de genes nuc, mecA e LPV foram utilizados protocolos Brakstad et al (5), Oliveira et al (6) e Gerard et al (7), respectivamente. Resultados. De 253 amostras testadas, 62 (24,5%) foram positivas para S. aureus, destas 4(6,45%) foram resistentes à meticilina, dois das quais (25%) foram LPV positivas, 58 (93,54%) foram sensíveis e seis (75%) foram positivas para PVL. Conclusões. Os resultados demonstram a colonização de SARM-AC em indivíduos saudáveis, a colonização foi maior em crianças e adultos jovens.

Inducible-NOS but not neuronal-NOS participate in the acute effect of TNF-alpha on hypothalamic insulin-dependent inhibition of food intake.

TNF-alpha acts on the hypothalamus modulating food intake and energy expenditure through mechanisms incompletely elucidated. Here, we explore the hypothesis that, to modulate insulin-induced anorexigenic signaling in hypothalamus, TNF-alpha requires the synthesis of NO. TNF-alpha activates signal transduction through JNK and p38 in hypothalamus, peaking at 10(-8) M. This is accompanied by the induction of expression of the inducible and neuronal forms of NOS, in both cases peaking at 10(-12) M. In addition, TNF-alpha stimulates NOS catalytic activity. Pre-treatment with TNF-alpha at a low dose (10(-12) M) inhibits insulin-dependent anorexigenic signaling, and this effect is abolished in iNOS but not in nNOS knockout mice.

Catalepsy induced by intra-striatal administration of nitric oxide synthase inhibitors in rats.

Systemic administration of nitric oxide synthase (NOS) inhibitors induces catalepsy in a dose-dependent manner in male Albino-Swiss mice. The objective of the present work was to investigate if similar effects occur in rats and if these effects are centrally mediated. The results showed that systemic administration of N(G)-nitro-L-arginine (L-NOARG, 40-160 mg/kg, i.p.), a non-selective NOS inhibitor, induced catalepsy in rats. Similar effects were found after intracerebroventricular (i.c.v.) injection of L-NOARG (50-200 nmol) or N(G)-nitro-L-arginine methylester (L-NAME, 100-200 nmol). The dose-response curve of the former compound, however, had an inverted U shape. The effect of L-NOARG (100 nmol, i.c.v.) was completely prevented by pre-treatment with L-arginine (300 nmol, i.c.v.) but not by D-arginine (300 nmol, i.c.v.). Intra-striatal injection of N(G)-monomethyl-L-arginine (L-NMMA, 100 nmol), 7-nitroindazole (7-NIO, 100 nmol), L-NOARG (25-100 nmol) or L-NAME (50-200 nmol) also induced catalepsy. Similar to i.c.v. administration, the latter two compounds produced bell-shaped dose-response curves. The cataleptic effect of intra-striatal administration of L-NAME (100 nmol) was reversed by local treatment with L-arginine (100 nmol). These results suggest that interference with the striatal formation of nitric oxide may induce significant motor effects in rats.

Delayed stress-induced antinociceptive effect of nitric oxide synthase inhibition in the dentate gyrus of rats.

Stimulation of the hippocampal formation can modulate nociceptive mechanisms, whereas painful stimuli can activate this structure. Stress exposure can produce plastic changes in the hippocampus. Nitric oxide (NO) is an important neuroregulatory agent present in the hippocampus. The objective of the present study was to investigate the effects of intrahippocampal administration of N(omega)-nitro-L-arginine methyl ester hydrochloride (L-NAME), an inhibitor of NO synthase (NOS), on nociceptive processes in stressed and nonstressed rats. Male Wistar rats (n=6-11/group) received unilateral microinjection of L-NAME (50-300 nmol/0.2 microl) into the dentate gyrus (DG) of the dorsal hippocampus. Immediately after the injection tail-flick reflex latency was measured. Stressed animals were submitted to 2 h of restraint and tested immediately or 1, 2, 5 or 10 days later. L-NAME failed to modify nociception in nonstressed rats. However, 5 days after, restraint L-NAME, at all doses tested, produced an antinociceptive effect (ANOVA, P<.05). The dose-response curve had an inverted U shape. L-NAME antinociceptive effect was antagonized by previous treatment with L-arginine (150 nmol/0.2 microl, P<.05). The results suggest that the modulation of nociceptive processes by NO in the dorsal hippocampus is dependent on previous stress exposure and on poststress interval.