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Previous issue date: 2017-03-10 === Conselho Nacional de Pesquisa e Desenvolvimento Cient?fico e Tecnol?gico - CNPq === The insular cortex (IC) receives afferent projections from prefrontal cortex, cingulate gyrus, olfactory bulb, basal nuclei and forms reciprocal connections with important limbic areas: amygdala and entorhinal cortex. These different connections indicate a possible involvement of the insular cortex in the process of learning and memory. Social recognition memory (SRM) is essential for forming social groups, establishing hierarchies and social and affective ties. Despite its importance, the knowledge about the brain structures and the cellular and molecular mechanisms involved in its processing is still scarce. Thus, the present study aimed to verify the participation of NMDA-glutamatergic, D1/D5-dopaminergic, H2-histaminergic, ?-adrenergic and 5-HT1A serotoninergic receptors, of the IC, in the consolidation of SRM. For this, male Wistar adult rats (300-330 g) were submitted to stereotaxic surgery for implantation of bilateral cannulae in the IC and, later, to the task of social discrimination. The task consists of 4 consecutive days of habituation to the experimental apparatus, which is an open-field box containing 2 acrilic cilinders, for 20 min. Twenty four hours after the last habituation session, the animals were placed in the open field in the presence of a juvenile (22 days postnatal) for 1 hour (sample phase). After 24 hours, the retention test occurred, for 5 min, in the presence of a juvenile previously met (familiar) and a new juvenile. Animals that received the intra-IC infusion of the antagonist D1/D5, ?-adrenergic or 5-HT1A receptor, immediately after the sample phase, impairs the consolidation of SRM. However, this effect was blocked by the concomitant intra-IC infusion of the agonist and the antagonist of the respective receptors. In addition, animals that received intra-IC infusion of the antagonists NMDA and H2 receptors, immediately after the sample phase, were able to consolidate the SRM. The results obtained in the present study suggest that the dopaminergic D1/D5, ?-adrenergic and serotonergic 5-HT1A receptors, but not the glutamatergic NMDA and the histaminergic H2 receptors, of the IC, participates in the consolidation of the SRM. === O c?rtex insular (CI) recebe proje??es aferentes do c?rtex pr?-frontal, giro cingulado, bulbo olfat?rio, n?cleos da base, al?m de formar conex?es rec?procas com importantes ?reas l?mbicas: am?gdala e c?rtex entorrinal. Estas diferentes conex?es indicam um poss?vel envolvimento do c?rtex insular no processo de aprendizado e mem?ria. A mem?ria de reconhecimento social (MRS) ? essencial para formar grupos sociais, estabelecer hierarquias e v?nculos sociais e afetivos. Apesar de sua import?ncia, ainda ? escasso o conhecimento sobre o papel das estruturas cerebrais e os mecanismos celulares e moleculares envolvidos em seu processamento e armazenamento. Assim, o presente trabalho teve como objetivo verificar a participa??o dos receptores glutamat?rgicos do tipo NMDA, dopamin?rgicos D1/D5, histamin?rgico H2, ?-adren?rgico e serotonin?rgico 5-HT1A, do c?rtex insular, no processo de consolida??o da MRS. Para isso, ratos Wistar machos adultos foram submetidos a uma cirurgia estereot?xica para implanta??o de c?nulas bilaterais no CI e, posteriormente, ? tarefa de discrimina??o social. Esta tarefa consiste de 4 sess?es di?rias de 20 min de habitua??o ao aparato experimental, que ? constitu?do de uma caixa de campo aberto contendo dois cilindros de acr?lico. Vinte e quatro horas ap?s a ?ltima sess?o de habitua??o os animais foram recolocados no aparato, na presen?a de um coespec?fico juvenil (22 dias p?s-natal) dentro de um dos cilindros, por 1 hora (sess?o de treino). Ap?s 24 horas os animais foram submetidos a uma sess?o de teste, de 5 min, na presen?a de um juvenil desconhecido e do juvenil previamente encontrado (familiar). Verificou-se que, os animais que receberam a infus?o intra-CI do antagonista dos receptores D1/D5, ?-adren?rgico ou 5-HT1A imediatamente ap?s a sess?o de treino, tiveram um preju?zo na consolida??o da MRS. Contudo, esse efeito foi bloqueado pela infus?o intra-CI concomitante do agonista e do antagonista dos respectivos receptores. Ainda, os animais que receberam a infus?o intra-CI do antagonista dos receptores NMDA ou H2 imediatamente ap?s a sess?o de treino, foram capazes de consolidar a MRS. Os resultados obtidos no presente trabalho sugerem que os receptores dopamin?rgicos D1/D5, ?-adren?rgicos e serotonin?rgicos 5-HT1A, mas n?o os glutamat?rgicos NMDA e os histamin?rgicos H2, do c?rtex insular participam da consolida??o da MRS.
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