O antagonismo do receptor de serotonina do tipo 7 da subst?ncia cinzenta periaquedutal dorsal reduz a ansiedade experimental basal, mas n?o aquela gerada pela retirada do etanol em ratos

• Main Author: Silveira, Marana Ali
• Other Authors: 28762725807
• Language: Portuguese
• Published: Universidade Federal do Rio Grande do Norte 2016
• Subjects: CNPQ::CIENCIAS BIOLOGICAS; Etanol; Abstin?ncia; Ansiedade; Labirinto em cruz elevado; Serotonina; 5-HT7; SB269970
• Online Access: http://repositorio.ufrn.br/handle/123456789/19862

Submitted by Automa??o e Estat?stica ([e-mail]) on 2016-02-22T23:19:51Z No. of bitstreams: 1 MaranaAliSilveira_DISSERT.pdf: 1961262 bytes, checksum: 5e69a835345f4defbd4448caed33cdd8 (MD5) === Approved for entry into archive by Arlan Eloi Leite Silva ([e-mail]) on 2016-02-26T00:38:54Z (GMT) No. of bitstreams: 1 MaranaAliSilveira_DISSERT.pdf: 1961262 bytes, checksum: 5e69a835345f4defbd4448caed33cdd8 (MD5) === Made available in DSpace on 2016-02-26T00:38:54Z (GMT). No. of bitstreams: 1 MaranaAliSilveira_DISSERT.pdf: 1961262 bytes, checksum: 5e69a835345f4defbd4448caed33cdd8 (MD5) Previous issue date: 2014-09-02 === Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES === Indiv?duos dependentes de etanol que diminuem ou interrompem a sua utiliza??o podem apresentar a S?ndrome de Abstin?ncia do ?lcool, caracterizada por sinais e sintomas desagrad?veis que favorecem a reca?da, dentre eles, a ansiedade. Por ser uma droga psicotr?pica, o etanol ? capaz de promover mudan?as comportamentais e neurofisiol?gicas, atuando sobre diversos sistemas de neurotransmiss?o, dentre outros o sistema seroton?rgico, que vem sendo diretamente relacionado aos estados aversivos, como ? o caso da ansiedade. O presente estudo teve por objetivo investigar a participa??o do receptor de serotonina do tipo 7 (5-HT7) da subst?ncia cinzenta periaquedutal dorsal (DPAG) na ansiedade experimental basal e naquela gerada pela retirada de etanol. Para isso, ratos Wistar com 75-100 dias foram submetidos a dois experimentos. No primeiro, os animais receberam as doses de 2,5; 5,0 e 10 nmoles do antagonista de receptor 5-HT7 SB269970(SB) ou ve?culo intra-DPAG e, dez minutos ap?s, foram expostos ao labirinto em cruz elevado (LCE). No dia seguinte, os animais foram submetidos aos mesmos tratamentos e testados no campo aberto (CA). No segundo experimento, os animais receberam concentra??es crescentes (2%, 4%, 6%) de etanol como ?nica fonte de dieta l?quida ou ?gua (grupo controle), ambos com acesso livre ? ra??o. Setenta e duas e noventa e seis horas ap?s a retirada do etanol, os animais receberam SB (2,5 e 5,0 nmoles) intra-DPAG dez minutos anteriores ao teste no LCE e no CA, respectivamente. No experimento 1, a dose do antagonista de 10 nmoles foi capaz de reverter a ansiedade gerada pela exposi??o ao LCE. No experimento 2, as doses ineficazes no LCE de SB (2,5 e 5,0 nmoles) n?o foram capazes de reverter a ansiedade gerada pela retirada de etanol no LCE, embora a dose de 2,5 nmoles de SB tenha revertido o seu efeito hipolocomotor neste teste. Esses resultados sugerem que o receptor 5- HT7 participa modulando a ansiedade experimental basal de ratos, mas n?o a ansiedade gerada pela retirada do etanol na DPAG. === Ethanol-dependent individuals who reduce or discontinue its use may present Alcohol Withdrawal Syndrome, which is characterized by unpleasant signs and symptoms, such as anxiety, that may trigger relapses. Ethanol, a psychotropic drug, is able to promote behavioral and neurophysiological changes, acting on different neurotransmitter systems, including the serotonergic, which has also been directly associated with aversive states, including anxiety. This study aimed to investigate the participation of type 7 serotonin receptor (5-HT7) of the dorsal periaqueductal gray (DPAG) on basal experimental anxiety and that caused by ethanol withdrawal. For this, 75-100 days old Wistar rats were subjected to two experiments. On the first one, animals underwent stereotactic surgery for implantation of guide cannulas used for administration of the drug directly into the DPAG. After seven days, the animals received doses of 2.5; 5 and 10 nmols of type 7 receptor antagonist SB269970 (SB) or vehicle intra-DPAG and, ten minutes after, they were exposed to elevated plus maze (EPM). In the following day, the animals were submitted to the same treatment and tested in the open field (OF). In the second experiment, animals received increasing concentrations (2%, 4%, 6%) of ethanol as the only source of liquid diet or water (control group), both with free access to chow. Seventy two hours and ninety six hours after the ethanol withdrawal, animals received SB (2.5 and 5.0 nmols) intraDPAG ten minutes before the test in the LCE and OF, respectively. In experiment 1, the dose of antagonist 10 nmols was able of reversing the anxiety generated by EPM. In the experiment 2, ineffective SB doses on the LCE (2.5 and 5.0 nmol) were not able to reverse the anxiety caused by the ethanol withdrawal in the EPM, although the dose of 2.5 nmols of SB has reversed its hipolocomotor effect in this test. This result suggests that the 5-HT7 receptor is involved in the modulation of the basal experimental anxiety in rats, but not in the anxiety caused by ethanol withdrawal in the DPAG.