Sex differences in aversive memory in rats: Possible role of extinction and reactive emotional factors

a b s t r a c t Studies usually show better spatial learning in males and stronger emotional memory in females. Spatial memory differences could relate to diverse strategies, while dissimilar stress reactions could cause emotional memory differences. We compared male and female rats in two emotional (classical emotional conditioning and aversive discrimination memory) and two emotionally ''neutral" tasks: (1) plus-maze discriminative avoidance, containing two open and two enclosed arms, one of which presenting aversive stimuli (light/noise). No differences were found in learning, retrieving, or basal emotional levels, while only male rats presented extinction of the task; (2) contextual fear conditioning -a cage was paired to mild foot shocks. Upon reexposure, freezing behavior was decreased in females; (3) spontaneous alternation -the animals were expected to alternate among the arms of a four-arm maze. No differences between genders were found and (4) open-field habituation was addressed in an arena which the rats were allowed to explore for 10 min. Habituation was similar between genders. Differences were found only in tasks with strong emotional contexts, where different fear responses and stress effects could be determinant. The lack of extinction of discriminative avoidance by females points out to stronger consolidation and/or impaired extinction of aversive memories

Clinical and endoscopic evaluantion of gastroesophageal reflux disease in patients successfully treated with esomeprazole Avaliação clínica e endoscópica da doença do refluxo gastroesofágico em pacientes tratados com esomeprazol

BACKGROUND: Esomeprazole, an S-isomer of omeprazole, is the first proton pump inhibitor developed as an optical isomer, and it has shown high healing rates in erosive esophagitis. AIM: To evaluate the efficacy and tolerability of esomeprazole in subjects with erosive esophagitis, according to the Los Angeles classification study design: an open, multi-center clinical study. MATERIAL AND METHODS: Two hundred and eighteen subjects with reflux esophagitis confirmed by endoscopy were included in an open, multi-center study in Brazil. All of them received esomeprazole 40 mg, once daily, for a 4-week period. Subjects who had unhealed esophagitis by week 4 continued the treatment for another 4 weeks. The primary efficacy endpoint was the healing rates by weeks 4 and 8. The secondary endpoints were the number of patients with symptom resolution by week 4, the number of days to sustained symptom resolution, number of symptom-free days and nights and safety and tolerability of the drug. RESULTS: Healing rates by weeks 4 and 8 were 82% (confidence interval: 77.4%-87.6%) and 96.1% (confidence interval: 93.5% - 98.8%), respectively. Ninety-nine (99%) of the patients had heartburn resolution by week 2. The most common adverse events were headache (4%), diarrhea (2.6%) and epigastric pain (2.2%). CONCLUSION: For the studied period, esomeprazole was shown to be a safe and well-tolerated drug, providing significant healing rates of mucosal breaks, regardless of LA classification, in patients with erosive esophagitis. Esomeprazole was also shown to be effective in quickly relieving symptoms.<br>RACIONAL: O esomeprazol, um isômero-S do omeprazol, é o primeiro inibidor da bomba de prótons desenvolvido como um isômero ótico e tem apresentado altos índices de cicatrização na esofagite erosiva. OBJETIVO: Avaliar a eficácia e tolerabilidade do esomperazol em pessoas com esofagite erosiva, classificada de acordo com a classificação de Los Angeles. MATERIAL E MÉTODOS: Duzentos e dezoito pacientes com esofagite de refluxo confirmada por endoscopia foram incluídos num estudo multicêntrico, aberto, no Brasil. Todos receberam 40 mg de esomeprazol, uma vez ao dia, por um período de 4 semanas. Aqueles que não cicatrizaram a esofagite ao final da 4ª semana continuaram o tratamento por mais 4 semanas. O objetivo primário de eficácia foi a taxa de cicatrização ao final da 4ª e 8ª semanas. Os objetivos secundários foram o número de pacientes com resolução dos sintomas ao final da 4ª semana, o número de dias com resolução sustentada dos sintomas, o número de dias e noites livres de sintomas e a segurança e tolerabilidade da droga. RESULTADOS: As taxas de cicatrização nas semanas 4 e 8 foram 82% (IC: 77,4%-87,6%) e 96,1% (IC: 93,5%-98,8%), respectivamente. Noventa e nove por cento dos pacientes tiveram resolução da pirose retroesternal na 2ª semana. Os eventos adversos mais comuns foram cefaléia (4%), diarréia (2,6%) e dor epigástrica (2,2%). CONCLUSÃO: Para o período estudado, o esomeprazol mostrou ser uma droga segura e bem tolerada, alcançando taxas significativas de cicatrização das soluções de continuidade da mucosa em pacientes com esofagite erosiva, independente do seu grau, de acordo com a classificação de Los Angeles. Mostrou-se, também, eficiente em rapidamente aliviar os sintomas decorrentes da doença do refluxo gastroesofágico