Análisis del conocimiento sobre los inhibidores selectivos de la recaptura de serotonina (ISRS) en el manejo de la depresión por médicos residentes y concurrentes de clínica médica de 5 hospitales de CABA / Review of the Knowledge on Selective Serotonin Reuptake Inhibitors (SSRIs) for Depression Management by Resident and Intern Physicians of the Medical Clinic of 5 Hospitals in CABA

Introducción: la depresión es un trastorno cada vez más prevalente alrededor del mundo. Los médicos generales son los profesionales de la salud más consultados por pacientes deprimidos. Más del 70% de los pacientes con depresión son vistos por médicos generales y no por especialistas en Psiquiatría. Según estudios realizados en Buenos Aires, más del 25% de los pacientes internados en Servicios de Clínica Médica en hospitales generales presenta depresión. Estos pacientes suelen ser atendidos y seguidos por médicos en formación, sean residentes o concurrentes de Clínica Médica. El objetivo del trabajo fue analizar el conocimiento sobre los inhibidores selectivos de la recaptura de serotonina (ISRS) que tienen los médicos residentes y concurrentes de Clínica Médica de 5 hospitales de la Ciudad Autónoma de Buenos Aires (CABA) y describir el tratamiento de un paciente depresivo por ellos. Material y métodos: se realizó un estudio descriptivo de corte transversal con un muestreo de tipo no probabilístico. Se utilizó como instrumento de medición un cuestionario semiestructurado organizado en dos secciones, una de datos demográficos que permiten caracterizar la muestra. La otra, de 15 ítems, explora los conocimientos sobre los ISRS y el tratamiento de la depresión. Dicho cuestionario fue revisado por 4 expertos. El instrumento es anónimo. Se aplicó a 59 médicos en formación en Clínica Médica, residentes y concurrentes, de 5 hospitales de la CABA, que participaron de forma voluntaria, durante el período agosto-septiembre de 2022. Resultados: la mayoría de los médicos en formación en Clínica Médica no tratan cuadros depresivos y, ante un paciente deprimido, solicitan la evaluación por un especialista en Salud Mental. Solo un 6,8% lo medica con un antidepresivo. Más del 75% de la muestra refiere recordar los conocimientos que tiene sobre de los ISRS de la cursada de Farmacología y un 13,6 de la cursada de Psiquiatría en la Facultad de Medicina. Conclusión: se observa un conocimiento deficitario sobre los ISRS en médicos residentes y concurrentes de Clínica Médica. Se considera necesario reforzar la formación sobre depresión y manejo de antidepresivos durante la residencia/concurrencia de Clínica Médica. (AU)

Introduction: depression is an increasingly common disorder around the world. General practitioners are the most frequently consulted health professionals by depressed patients. More than 70% of all depressed patients receive treatment by general practitioners and not by psychiatric specialists. According to studies conducted in Buenos Aires, more than 25% of all patients admitted to the Clinical Services in public hospitals present depression. These patients are usually under the care and follow-up of clinical trainee physicians, residents, or interns.This study aimed to analyze the knowledge about selective serotonin reuptake inhibitors (SSRIs) of clinical trainee residents and interns in five hospitals in the Ciudad Autónoma de Buenos Aires (CABA) and to describe their treatment of a depressive patient. Material and methods: we conducted a descriptive cross-sectional study with a non-probabilistic sampling. We used a semi-structured questionnaire arranged into two sections as a measuring tool. One, with demographic data to describe the sample. The other, with 15 items, explores respondents' knowledge of SSRIs and the treatment of depression. Four experts reviewed the questionnaire, which was anonymous. We applied it to 59 clinical medical trainees, residents, and interns from five CABA hospitals who volunteered to participate during August-September 2022. Results: most clinical trainees do not treat depressive conditions and, when confronted with a depressed patient, request an assessment by a Mental Health specialist. Only 6.8% medicate the patient with an antidepressant. More than 75% of the sample reported remembering their knowledge of SSRIs from the Pharmacology course and 13.6% from the Psychiatry course at the School of Medicine. Conclusion: there is a deficient knowledge about SSRIs in trainee residents and interns of Clínica Médica. We believe it is necessary to reinforce training on depression and management of antidepressants during residency/internship practice in Clínica Médica. (AU)

Indicación de N-acetilcisteína en distintas formas de toxicidad por paracetamol / Indication of n-acetylcysteine in differents forms of paracetamol toxicity

Introducción: la hepatotoxicidad por paracetamol está relacionada con la formación del metabolito N-acetil-parabenzoquinoneimina (NAPQI) y su falta de detoxificación a través del glutatión, cuyas reservas se deplecionan en el contexto de una sobredosis. La administración de N-acetilcisteína (NAC) como sustancia dadora de grupos tioles (-SH) contribuye a la prevención del daño hepático que puede desarrollarse con dosis terapéuticas o tóxicas. Métodos: se comentan 5 casos de exposición a paracetamol en los cuales se administró NAC por alteración de la función hepática. La gravedad de los cuadros varió en función de las dosis y del tiempo de latencia hasta la consulta. Resultados: cuatro pacientes ingirieron una única dosis tóxica y una paciente recibió la dosis diaria máxima de paracetamol de 4000 mg/día durante 5 días. La paciente que consultó dentro de las 4 horas posteriores a la ingesta no presentó elevación de transaminasas. Todas las pacientes recibieron NAC y sus valores de enzimas hepáticas se normalizaron al momento del alta. Conclusión: la administración temprana de NAC puede ser útil para prevenir daño hepático tanto en ingestas de dosis tóxicas, como en casos de utilización de dosis terapéuticas máximas durante varios días. (AU)

Introduction: paracetamol hepatotoxicity is related to the formation of the metabolite N-acetyl-parabenzoquinoneimine (NAPQI) and its lack of detoxification through glutathione, whose reserves are depleted in paracetamol overdose. The administration of N-acetylcysteine (NAC) as a donor of sulfhydryl groups (-SH) can prevent liver damage that could even occur with therapeutic or toxic doses. Methods: 5 cases of exposure to paracetamol are discussed, in which NAC was administered due to impaired liver function. These manifestations presented different severity depending on the drug doses and the time until medical consultation. Results: four patients ingested single toxic doses and one patient received the maximum daily dose of paracetamol of 4000 mg/day for 5 days. The patient who consulted within 4 hours after ingestion did not present elevation of transaminases. All patients received NAC, with normal liver enzymes at discharge. Conclusion: the early administration of NAC may be useful to prevent liver damage both in toxic dose intakes and in cases of use of maximum therapeutic doses for several days. (AU)

Which of available selective serotonin reuptake inhibitors (SSRIs) is more effective in treatment of premature ejaculation? A randomized clinical trial

ABSTRACT Purpose: To compare the efficacy and safety of available selective serotonin reuptake inhibitors (SSRIs) in order to find the most effective drug with the least number of side effects in treatment of premature ejaculation (PE). Materials and Methods: This study was a randomized clinical trial. Four hundred and eighty patients with PE in the 4 groups referred to Imam Reza hospital Tehran, Iran from July 2018 to February 2019 were enrolled in the study. The patients received sertraline 50mg, fluoxetine 20mg, paroxetine 20mg and citalopram 20mg, every 12 hours daily. The intravaginal ejaculatory latency time (IELT) before treatment, fourth and eighth weeks after treatment was recorded by the patient's wife with a stopwatch. Results: Mean IELT before, 4 and 8 weeks after treatment in four groups were: sertraline 69.4±54.3, 353.5±190.4, 376.3±143.5; fluoxetine 75.5±64.3, 255.4±168.2, 314.8±190.4; paroxetine 71.5±69.1, 320.7±198.3, 379.9±154.3; citalopram 90.39±79.3, 279.9±192.1, 282.5±171.1 seconds, respectively. The ejaculation time significantly increased in all groups (p <0.05), but there was no significant difference between the groups (P=0.75). Also, there was no significant difference in drugs side effects between groups (p >0.05). The most common side effects were drowsiness and dyspepsia, which were not severe enough to cause discontinuation of the drug. Conclusions: All available SSRIs were effective and usually had no serious complications. In patients who did not respond to any of these drugs, other SSRI drugs could be used as a salvage therapy.

La respuesta excelente al tratamiento en pacientes con cáncer diferenciado de tiroides se mantiene a lo largo del seguimiento independientemente del riesgo de recurrencia inicial / Excellent response to treatment in patients with differentiated thyroid cancer is maintained throughout follow-up regardless of the risk of initial recurrence

Resumen Introducción: El riesgo de recurrencia en cáncer diferenciado de tiroides (CDT) se utiliza para determinar la frecuencia de las respuestas estructurales incompletas o excelentes con un valor predictivo positivo cercano al 30%. El riesgo dinámico, que evalúa la respuesta inicial al tratamiento demostró tener una proporción de varianza explicada de hasta el 80%. Por otro lado, en nuestro medio es fácil establecer la respuesta inicial, pero muchas veces es dificultoso determinar el riesgo de recurrencia desde donde partió el paciente. A esto hemos denominado "la silla rota" en pacientes con CDT. Materiales y métodos: Se realizó el análisis retrospectivo incluyendo 340 pacientes con los siguientes criterios:1) edad ≥18 años al momento del diagnóstico, 2) tratamiento inicial con tiroidectomía total y ablación con radioyodo, 3) seguimiento mínimo ≥3 años (excepto si ocurrió metástasis a distancia o muerte antes de ese tiempo), 4) datos anatomopatológicos y estudios complementarios suficientes para poder determinar tanto el riesgo de recurrencia como la respuesta inicial (evaluada en los primeros 6 meses a 2 años de seguimiento) y el estado al final del seguimiento (al momento de la última consulta). Objetivos: Describir la evolución de la respuesta inicial al final del seguimiento para demostrar que esta es la definición más importante, independientemente del riesgo de recurrencia al diagnóstico en pacientes con CDT. Resultados: El 36% de los pacientes presentó una respuesta excelente al tratamiento inicial (n=122) y de ellos, ninguno presentó evidencia estructural de enfermedad al final del seguimiento, independientemente del RR inicial. Conclusiones: La denominada "silla rota" parecería "repararse" correctamente cuando el paciente presenta una respuesta excelente al tratamiento, ya que esta se mantiene al final del seguimiento independientemente del RR inicial. La carencia de un correcto RR inicial no parecería ser imprescindible en pacientes con respuestas excelentes al tratamiento.

ABSTRACT Background: The risk of recurrence (RR) stratification system has been proposed as a useful tool for stablishing the frequency of the structural incomplete and excellent response-to-treatment in patients with differentiated thyroid cancer (DTC). However, the available information at diagnosis could be insufficient to accurately determine the initial RR. We called this situation "the broken chair". Although many studies have shown that the initial response to treatment usually predicts the final outcome, it is not clear if the final outcome could be different in the distinctive responses to treatment, if we analyze it together with the initial RR. Purpose: To investigate the outcomes of patients by comparing both situations: the initial RR and the initial response to treatment with the final outcome to establish if there was a different frequency of structural incomplete response at the end of follow-up. Methods: Retrospective review of 340 DTC patients followed up for at least 3 years after initial total thyroidectomy and radioactive iodine ablation (RAI). We assessed the initial response as the best response to therapy during the first 2 years, and the final response to therapy as the status at the end of follow-up, according to the definitions of the 2015 ATA guidelines. Conclusions: An excellent response to treatment during the first two years of follow-up can fix the "broken chair" in patients treated with DTC who received remnant ablation and it is independent of the initial RR. Results: None of the patients that achieved an initial excellent response to treatment (n=122, 36%), showed structural evidence of disease in the entire follow-up despite their initial RR.

Effects of ganglioside G(M1) and erythropoietin on spinal cord lesions in rats: functional and histological evaluations

OBJECTIVE: To evaluate the functional and histological effects of ganglioside G(M1) and erythropoietin after experimental spinal cord contusion injury. METHODS: Fifty male Wistar rats underwent experimental spinal cord lesioning using an NYU-Impactor device and were randomly divided into the following groups, which received treatment intraperitoneally. The G(M1) group received ganglioside G(M1) (30 mg/kg); the erythropoietin group received erythropoietin (1000 IU/kg); the combined group received both drugs; and the saline group received saline (0.9%) as a control. A fifth group was the laminectomy group, in which the animals were subjected to laminectomy alone, without spinal lesioning or treatment. The animals were evaluated according to the Basso, Beattie and Bresnahan (BBB) scale, motor evoked potential recordings and, after euthanasia, histological analysis of spinal cord tissue. RESULTS: The erythropoietin group had higher BBB scores than the G(M1) group. The combined group had the highest BBB scores, and the saline group had the lowest BBB scores. No significant difference in latency was observed between the three groups that underwent spinal cord lesioning and intervention. However, the combined group showed a significantly higher signal amplitude than the other treatment groups or the saline group (p<0.01). Histological tissue analysis showed no significant difference between the groups. Axonal index was significantly enhanced in the combined group than any other intervention (p<0.01). CONCLUSION: G(M1) and erythropoietin exert therapeutic effects on axonal regeneration and electrophysiological and motor functions in rats subjected to experimental spinal cord lesioning and administering these two substances in combination potentiates their effects.

effectiveness of tramadol in treatment of premature ejaculation on-demand basis

Premature ejaculation [PE] is a worldwide problem. Selective serotonin reuptake inhibitors [SSRIs] are widely used "off label" as pharmacotherapeutic agents in the treatment of PE. Assess the efficacy of Tramadol for on-demand treatment of PE. During the period December 2008 through November 2009, 60 married men visited the surgical specialties hospital urology outpatient and consultancy clinics complaining of premature ejaculation were enrolled in this study. Intravaginal ejaculation latency time [IVELT] was used as an objective tool to assess the efficacy of the investigated treatment. Single-blind, placebo-controlled therapeutic trial was conducted on 60 patients with lifelong PE. PE was defined as IVELT of <2 minutes in at least 80% of intercourse episodes. The patients cohort was randomised into 2 equal sized groups. The intervention group [n=30] used 50 mg tablet of Tramadol hydrochloride, while the control group [n=30] used a placebo tablet for 8 weeks. Drugs were taken 1-2 hours before sexual activity, and sexual intercourse was required at least once per week. IVELT was timed by a stopwatch at each intercourse. The mean IVELT after tramadol and placebo significantly increased from 73.1 and 67.9 seconds to approximately 442.1 and 113.3 seconds, respectively [P < 0.001]. Sexual satisfaction was used to assess the cut-off values of IVELT in defining the minimal and best clinical response to treatment. There was no withdrawal symptoms recorded following the use of tramadol or placebo, but more adverse events were associated with tramadol treatment. Tramadol seems to provide significantly better results in terms of IVELT and intercourse satisfaction versus placebo. Further studies are required to draw final conclusions on the efficacy of this drug in premature ejaculation.

Enhanced local anesthetic action of mepivacaine from the bioadhesive gels

Mepivacaine, an amide-type local anesthetic, has been used to relieve local pain. Among the many drug delivery systems, transdermal drug delivery has some advantages, as it provides controlled drug delivery for an extended period of time. To develop new gel formulations that have suitable bioadhesion, the bioadhesive force of hydroxypropyl methylcellulose [HPMC] was assessed using an auto-peeling tester. The effect of drug concentration on drug release from 2% HPMC gel was studied using synthetic cellulose membrane at 37 +/- 0.5°C. The drug concentrations tested were 0.5, 1, 1.5, 2, and 2.5%. The effect of temperature on drug release from the 2% drug gel was evaluated at 27, 32, 37 and 42°C. To increase the skin permeation of mepivacaine from HPMC gel, enhancers such as saturated and unsaturated fatty acids, pyrrolidones, propylene glycol derivatives, glycerides, and non-ionic surfactants were incorporated into the mepivacaine-HPMC gels. The enhancing effect of the enhancer on drug permeation was then examined in the modified Keshary-Chien cell. For the efficacy study, the anesthetic action of the formulated mepivacaine gel containing enhancer and vasoconstrictor was evaluated with the tail-flick analgesimeter. Among the various kinds of HPMC, HPMC-K100M gel showed the highest viscosity and bioadhesive force. As the viscosity of the HPMC gels increased, the bioadhesive forces increased. Increasing the drug concentration or temperature increased the drug release rate. Among the enhancers used, polyoxyethylene 2-oleyl ether showed the greatest enhancement of permeation. Based on the area under the efficacy curve of the rat tail flick test curve, mepivacaine gel containing polyoxyethylene 2-oleyl ether and tetrahydrozoline showed prolonged and increased local anesthetic action compared to the control. For bioadhesive mepivacaine gels with enhanced local anesthetic action, mepivacaine gels containing penetration enhancer and vasoconstrictor could be developed with the bioadhesive polymer, HPMC

Chronic treatment with the nitric oxide synthase inhibitor, L-NAME, attenuates estradiol-mediated improvement of learning and memory in ovariectomized rats

INTRODUCTION: The role of ovarian hormones and nitric oxide in learning and memory has been widely investigated. OBJECTIVE: The present study was carried out to evaluate the effect of the nitric oxide synthase (NOS) inhibitor, N (G)-nitro-L-arginine methyl ester (L-NAME), on the ability of estradiol to improve learning in OVX rats using the Morris water maze. METHODS: Forty rats were divided into five groups: (1) ovariectomized (OVX), (2) ovariectomized-estradiol (OVX-Est), (3) ovariectomized-L-NAME 10 (OVX-LN 10), (4) ovariectomized-L-NAME 50 (OVX-LN 50) and (5) ovariectomized-estradiol-L-NAME 50 (OVX-Est-LN 50). The animals in the OVX-Est group were treated with a weekly injection of estradiol valerate (2 mg/kg; i.m.). The OVX-LN 10 and OVX-LN 50 groups were treated with daily injections of 10 and 50 mg/kg L-NAME (i.p.), respectively. The animals in the OVX-Est-LN 50 group received a weekly injection of estradiol valerate and a daily injection of 50 mg/kg L-NAME. After 8 weeks, all animals were tested in the Morris water maze. RESULTS: The animals in the OVX-Est group had a significantly lower latency in the maze than the OVX group (p<0.001). There was no significant difference in latency between the OVX-LN 10 and OVX-LN 50 groups in comparison with the OVX group. The latency in the OVX-Est-LN 50 group was significantly higher than that in the OVX-Est group (p<0.001). CONCLUSION: These results show that L-NAME treatment attenuated estradiol-mediated enhancement of spatial learning and memory in OVX rats, but it had no significant effect in OVX rats without estrogen, suggesting an interaction of nitric oxide and estradiol in these specific brain functions.

Morphine infusions into the rostrolateral periaqueductal gray affect maternal behaviors

It is well established that morphine inhibits maternal behaviors. Previous studies by our group have shown activation of the rostrolateral periaqueductal gray (rlPAG) upon inhibition-intended subcutaneous injections of morphine. In this context, we demonstrated that a single naloxone infusion into the rlPAG, following this opioid-induced inhibition, reactivated maternal behaviors. Since these data were obtained by using peripheral morphine injections, the present study was designed to test whether morphine injected directly into the rlPAG would affect maternal behaviors. Our hypothesis that morphine acting through the rlPAG would disrupt maternal behaviors was confirmed with a local infusion of morphine. The mothers showed shorter latency for locomotor behavior to explore the home cage (P = 0.049). Inhibition was especially evident regarding retrieving (P = 0.002), nest building (P = 0.05) and full maternal behavior (P = 0.023). These results support the view that opioidergic transmission plays a behaviorally meaningful inhibitory role in the rostrolateral PAG.

Chlorpheniramine impairs functional recovery in Carassius auratus after telencephalic ablation

We determined the effect of an H1 receptor antagonist on the functional recovery of Carassius auratus submitted to telencephalic ablation. Five days after surgery the fish underwent a spatial-choice learning paradigm test. The fish, weighing 6-12 g, were divided into four groups: telencephalic ablation (A) or sham lesion (S) and saline (SAL) or chlorpheniramine (CPA, ip, 16 mg/kg). For eight consecutive days each animal was trained individually in sessions separated by 24 h (alternate days). Training trials (T1-T8) consisted of finding the food in one of the feeders, which were randomly blocked for each subject. Animals received an intraperitoneal injection of SAL or CPA 10 min after the training trials. The time spent by the animals in each group to find the food (latency) was analyzed separately at T1 and T8 by the Kruskal-Wallis test, followed by the Student Newman-Keuls test. At T1 the latencies (mean ± SEM) of the A-SAL (586.3 ± 13.6) and A-CPA (600 ± 0) groups were significantly longer than those of the S-SAL (226.14 ± 61.15) and S-CPA (356.33 ± 68.8) groups. At T8, the latencies of the A-CPA group (510.11 ± 62.2) remained higher than those of the other groups, all of which showed significantly shorter latencies (A-SAL = 301.91 ± 78.32; S-CPA = 191.58 ± 73.03; S-SAL = 90.28 ± 41) compared with T1. These results support evidence that training can lead to functional recovery of spatial-choice learning in telencephalonless fish and also that the antagonist of the H1 receptor impairs it.

The effects of bromazepam on the early stage of visual information processing (P100)

The early stages of visual information processing, involving the detection and perception of simple visual stimuli, have been demonstrated to be sensitive to psychotropic agents. The present study investigated the effects of an acute dose of bromazepam (3 mg), compared with placebo, on the P100 component of the visual evoked potential and reaction time. The sample, consisting of 14 healthy subjects (6 male and 8 female), was submitted to a visual discrimination task, which employed the "oddball" paradigm. Results suggest that bromazepam (3 mg) impairs the initial stage of visual information processing, as observed by an increase in P100 latency.

Os estágios iniciais do processamento da informação visual, envolvendo a percepção e detecção de um estímulo visual simples, tem demonstrado serem sensíveis a agentes psicotrópicos. O presente estudo investigou os efeitos de uma dose aguda de bromazepam (3 mg), comparado com placebo, no componente P100 do potencial evocado visual e no tempo de reação. A mostra consistiu de 14 sujeitos sadios (6 homens e 8 mulheres), submetidos a uma tarefa de discriminação visual, a qual empregou o paradigma "oddball". Os resultados sugerem que o bromazepam (3 mg) prejudica o estágio inicial do processamento da informação visual, como observado pelo aumento da latência do P100.

Efficacy of splinting and oral steroids in the treatment of carpal tunnel syndrome: a prospective randomized clinical and electrophysiological study.

OBJECTIVE: To study the efficacy of splinting and oral steroids in the management of carpal tunnel syndrome (CTS). DESIGN: Prospective, randomized, open-label, clinical and electrophysiological study with 3-month follow-up. MATERIALS AND METHODS: Forty patients with CTS were randomly divided into splint group (N-20), wearing splint in neutral position for 4 weeks; and steroid group (N-20), who received oral prednisolone 20 mg/day for 2 weeks followed by 10 mg/day for 2 weeks. Clinical and electrophysiological evaluations were done at baseline and at 1-month and 3-month follow-up. Independent 't' test and paired 't' test were used for statistical analysis. OUTCOME MEASURES: Primary outcome measure was the symptom severity score and functional status score. Secondary outcome measures were median nerve sensory and motor distal latency and conduction velocity. RESULTS: At the end of 3 months, statistically significant improvement was seen in symptom severity score and functional status score in both groups (P<0.001). Median nerve sensory distal latency and conduction velocity also improved significantly in both the groups at 3 months. Improvement in motor distal latency was significant (P=0.001) at 3 months in steroid group, while insignificant improvement (P=0.139) was observed in splint group. On comparing the clinical and electrophysiological improvement between the two groups, except for the functional status score, there was no significant difference at 3-month follow-up. Improvement in functional status score was significantly more in steroid group (P=0.03). CONCLUSION: There was significant improvement in both groups, clinically as well as electrophysiologically, at 3 months. On comparing the efficacy of the two treatment methods, except for the functional status score, there was no significant difference between the two groups.

Effects of captopril and losartan on thermal and chemical induced pain in mice.

Angiotensin converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers antagonists (ARAs) are widely used compounds in various cardiovascular disorders. ACEIs, but not ARAs, inhibit the enzyme dipeptidyl carboxypeptidase which is involved in the conversion of angiotensin I to II and degradation of kinins like bradykinin and substance P. Bradykinin and substance P are potent mediators of inflammation and pain. Hence the study was undertaken to evaluate the effects of captopril (an ACEI) and losartan (an ARA-AT1 receptor antagonist) on thermal and chemical induced nocioception by employing hot plate and acetic acid induced writhing tests respectively in mice. Inbred albino mice weighing between 25-30 g were used and they were divided into two sets, each set containing 7 groups. Control groups received normal saline and the remaining six groups received three doses (0.5, 1 and 2 mg/kg) of captopril and three doses (0.5, 1 and 2 mg/kg) of losartan. Drugs were administered intraperitoneally fifteen minutes before placing the animal over the hot plate or 30 minutes before injecting 0.6% acetic acid. Both drugs dose dependently reduced the reaction time in hot plate method. In chemical induced writhing test, both the drugs reduced the latency of onset of writhing and in captopril pretreated groups, acetic acid induced sustained abdominal contraction without any intermittent relaxation. However, in losartan pretreated animals acetic acid just increased the number of writhings without sustained abdominal contraction. Thus, our study suggests that both drugs have hyperalgesic effects.

Evaluation of cognitive brain functions in caffeine users: a P3 evoked potential study.

Caffeine is one of the most widely consumed stimulant drugs of the modern world. It brings about a feeling of well-being, relaxation, increased alertness and concentration. Its effects have been studied on brain function and behavior using mood questionnaires, reaction time tests, memory tests, EEG and of late Event Related Potentials (ERPs). This study evaluates the response of caffeine on ERPs and Reaction Time (RT) using auditory "oddball" paradigm. Forty undergraduate medical students volunteered for the study and their ERPs and RT were recorded before and after 40 minutes of ingestion of caffeine. There was a non-significant decrease in latency of N1, P2, N2 and P3 and a significant decrease in Reaction Time after caffeine consumption. The amplitude of P3 showed a significant increase after intake of caffeine. The results of this study indicate that caffeine leads to facilitation of information processing and motor output response of the brain.

Effect of Erythrina velutina and Erythrina mulungu in rats submitted to animal models of anxiety and depression

Erythrina velutina (EV) and Erythrina mulungu (EM), popularly used in Brazil as tranquilizing agents, were studied. The effects of acute and chronic oral treatment with a water:alcohol extract of EV (7:3, plant grounded stem bark; acute = 100, 200, 400 mg/kg; chronic = 50, 100, 200 mg/kg) were evaluated in rats (N = 11-12) submitted to the elevated T-maze (for avoidance and escape measurements) model of anxiety. This model was selected for its presumed capacity to elicit specific subtypes of anxiety disorders recognized in clinical practice: avoidance has been related to generalized anxiety and escape to panic. Additionally, animals were treated with the same doses of EV and EM (water:alcohol 7:3, inflorescence extract) and submitted to the forced swim test for the evaluation of antidepressant activity (N = 7-10). Both treatment regimens with EV impaired elevated T-maze avoidance latencies, without altering escape, in a way similar to the reference drug diazepam (avoidance 1, mean ± SEM, acute study: 131.1 ± 45.5 (control), 9.0 ± 3.3 (diazepam), 12.7 ± 2.9 (200 mg/kg), 28.8 ± 15.3 (400 mg/kg); chronic study: 131.7 ± 46.9 (control), 35.8 ± 29.7 (diazepam), 24.4 ± 10.4 (50 mg/kg), 29.7 ± 11.5 (200 mg/kg)). Neither EV nor EM altered measurements performed in the forced swim test, in contrast to the reference drug imipramine that significantly decreased immobility time after chronic treatment. These results were not due to motor alterations since no significant effects were detected in an open field. These observations suggest that EV exerts anxiolytic-like effects on a specific subset of defensive behaviors which have been associated with generalized anxiety disorder.

Analysis of the influence of bromazepam on cognitive performance through the visual evoked potential (P300)

Benzodiazepínicos têm sido utilizados no tratamento farmacológico da ansiedade há mais de quatro décadas. No entanto, poucos estudos têm combinado bromazepam e potencial evocado relacionado a evento (PRE). O presente estudo teve por objetivo investigar os efeitos modulatórios desta droga na dinâmica cerebral. Especificamente, os efeitos de 3mg de bromazepam no componente P300 do PRE foram analisados em um experimento duplo-cego. A amostra consistiu de 15 sujeitos sadios (7 homens e 8 mulheres), submetidos a uma tarefa de discriminação visual utilizando o paradigma "oddball". Medidas eletrofisiológicas (P300) e comportamentais (stroop, digit span, e tempo de reação) foram analisadas em três condições experimentais: placebo 1, placebo 2 e bromazepam. Os resultados sugerem que os efeitos de 3mg de bromazepam em processos cognitivos não são aparentes. Apesar do que parece irrefutável na literatura, o bromazepam não produziu efeitos evidentes nas variáveis comportamentais e eletrofisiológicas analisadas.

The terrestrial Gastropoda Megalobulimus abbreviatus as a useful model for nociceptive experiments: effects of morphine and naloxone on thermal avoidance behavior

We describe the behavior of the snail Megalobulimus abbreviatus upon receiving thermal stimuli and the effects of pretreatment with morphine and naloxone on behavior after a thermal stimulus, in order to establish a useful model for nociceptive experiments. Snails submitted to non-functional (22°C) and non-thermal hot-plate stress (30°C) only displayed exploratory behavior. However, the animals submitted to a thermal stimulus (50°C) displayed biphasic avoidance behavior. Latency was measured from the time the animal was placed on the hot plate to the time when the animal lifted the head-foot complex 1 cm from the substrate, indicating aversive thermal behavior. Other animals were pretreated with morphine (5, 10, 20 mg/kg) or naloxone (2.5, 5.0, 7.5 mg/kg) 15 min prior to receiving a thermal stimulus (50°C; N = 9 in each group). The results (means ± SD) showed an extremely significant difference in response latency between the group treated with 20 mg/kg morphine (63.18 ± 14.47 s) and the other experimental groups (P < 0.001). With 2.5 mg/kg (16.26 ± 3.19 s), 5.0 mg/kg (11.53 ± 1.64 s) and 7.5 mg/kg naloxone (7.38 ± 1.6 s), there was a significant, not dose-dependent decrease in latency compared to the control (33.44 ± 8.53 s) and saline groups (29.1 ± 9.91 s). No statistically significant difference was found between the naloxone-treated groups. With naloxone plus morphine, there was a significant decrease in latency when compared to all other groups (minimum 64 percent in the saline group and maximum 83.2 percent decrease in the morphine group). These results provide evidence of the involvement of endogenous opioid peptides in the control of thermal withdrawal behavior in this snail, and reveal a stereotyped and reproducible avoidance behavior for this snail species, which could be studied in other pharmacological and neurophysiological studies.

Effects of caffeine on visual evoked potencial (P300) and neuromotor performance

Os efeitos estimulantes da cafeína no desempenho cognitivo vêm sendo amplamente investigados. O potencial evocado visual (P300) tem sido empregado em estudos recentes que buscam elucidar os mecanismos excitatórios da cafeína através de métodos neurofisiológicos. Neste contexto, o presente estudo objetivou examinar as variações geradas pela cafeína em respostas eletrofisiológicas (latência do P300) e determinar modificações no desempenho cognitivo e motor. Para tanto, 15 indivíduos hígidos, sendo 9 mulheres e 6 homens (26 ± 5 anos, 67 ± 12,5 kg) foram submetidos por três vezes à seguinte rotina: aquisição de sinais eletroencefalográficos, Word Color Stroop Test e tarefa de discriminação visual. Foi administrada uma cápsula gelatinosa de 400 mg de cafeína ou de placebo (P1 e P2) em um desenho randomizado duplo-cego cruzado. Foi empregada a ANOVA com um fator e post hoc de Tukey - HSD para a comparação das variáveis nos momentos C, P1 e P2. O momento cafeína apresentou redução não significativa no tempo de reação, no tempo de execução do Stroop e na latência em Cz. Observou-se também aumento não significativo no escore bruto do Stroop e na latência em Pz. O único resultado significativo encontrado foi na latência em Fz. Assim, pode-se concluir que a tendência favorável à ingestão de cafeína na melhora das respostas cognitivas pode estar relacionada a mudanças em regiões específicas do cérebro, como o córtex frontal, área amplamente relacionada com os processos de atenção.

The effect of L-arginine on the memory impairing action of phenobarbitone in rats that convulsed after the injection of picrotoxin.

Nitric oxide (NO) has been demonstrated to enhance memory formation in experimental animals. However, the effect of NO precursor, L-arginine has never been tested on the memory impairing action of the aniepileptic drug, phenobarbitone independently and concurrently with the convulsant, picrotoxin (PCT). In view of this, in the present study, rats that acquired the shock avoidance task were treated with PCT (5 mg/ kg). Twenty four h later these animals were injected with L-arginine (500, 1000 mg/kg) and phenobarbitone (10, 20 mg/kg). Retention of the acquired task was tested 30 min later. The effect of these compounds were correlated with the changes produced by them on the concentration of NO in the brain. PCT and phenobarbitone (20 mg/kg) inhibited memory process independently and concurrently. NO concentration was not altered by phenobarbitone but was decreased in PCT-treated animals. L-arginine (1000 mg/kg) increased the concentration of NO in PCT and phenobarbitone treated animals and prevented these compounds from impairing memory process independently and concurrently. These results lead to a conclusion that L-arginine may be used in combination with phenobarbitone to prevent both the cognitive side effect of the antiepileptic drug and the impairment of memory that is associated with the convulsion disorder.

The effect of ephedrine on the onset time of rocuronium in Thai patients.

The aim of this study was to determine the effect of ephedrine on the onset time of rocuronium. The study population was 60 ASA physical status 1 and 2 patients, aged 15-60 years scheduled for elective surgery under general anesthesia at Ramathibodi Hospital. The patients were randomly assigned into 2 groups. Group I (ephedrine group), ephedrine 70 microg/kg was given 1 minute before induction and group II (control group), saline was given instead of ephedrine and midazolam 7.5 mg was given orally 30-60 minutes before the induction. Anesthesia was induced with fentanyl 1 microg/kg and sodium thiopentone 3-5 mg/kg. The patient was intubated with 0.9 mg/kg of rocuronium. The intubation time (from rocuronium administration to the time of intubation) was predetermined by the Dixon's up and down method (with 5 seconds as a step size) for each patient and started at 60 seconds for the first patient in each group. The intubation time in the ephedrine group (39.41 +/- 4.64 seconds) was significantly different from the control group (59.17 +/- 9.00 seconds); p-value < 0.01. The hemodynamics were similar in both groups. Conclusion: Intravenous ephedrine shortened the onset time of rocuronium with no significant adverse hemodynamic effects. As an alternative to suxamethonium for rapid intubation, the authors recommend the use of ephedrine 70 microg/kg at one minute before induction followed by 0.9 mg/kg of rocuronium intravenously in healthy patients. The intubation could be achieved at 40 seconds after the administration.