Data/hora: 09/06/2024 02:30:56

Provedor de dados: 	56	
País: 	Brazil	
Título: 	Cholinergic-opioidergic interaction in the central amygdala induces antinociception in the guinea pig	
Autores: 	Leite-Panissi,C.R.A.; Brentegani,M.R.; Menescal-de-Oliveira,L.	
Data: 	2004-10-01	
Ano: 	2004	
Palavras-chave: 	Antinociception; Vocalization test; Cholinergic-opioidergic interaction; Amygdala; Naloxone; Atropine.	
Resumo: 	Several studies have demonstrated the involvement of the central nucleus of the amygdala (CEA) in the modulation of defensive behavior and in antinociceptive regulation. In a previous study, we demonstrated the existence of a cholinergic-opioidergic interaction in the CEA, modulating the defensive response of tonic immobility in guinea pigs. In the present study, we investigated a similar interaction in the CEA, but now involved in the regulation of the nociceptive response. Microinjection of carbachol (2.7 nmol) and morphine (2.2 nmol) into the CEA promoted antinociception up to 45 min after microinjection in guinea pigs as determined by a decrease in the vocalization index in the vocalization test. This test consists of the application of a peripheral noxious stimulus (electric shock into the subcutaneous region of the thigh) that provokes the emission of a vocalization response by the animal. Furthermore, the present results demonstrated that the antinociceptive effect of carbachol (2.7 nmol; N = 10) was blocked by previous administration of atropine (0.7 nmol; N = 7) or naloxone (1.3 nmol; N = 7) into the same site. In addition, the decrease in the vocalization index induced by the microinjection of morphine (2.2 nmol; N = 9) into the CEA was prevented by pretreatment with naloxone (1.3 nmol; N = 11). All sites of injection were confirmed by histology. These results indicate the involvement of the cholinergic and opioidergic systems of the CEA in the modulation of antinociception in guinea pigs. In addition, the present study suggests that cholinergic transmission may activate the release of endorphins/enkephalins from interneurons of the CEA, resulting in antinociception.	
Tipo: 	Info:eu-repo/semantics/article	
Idioma: 	Inglês	
Identificador: 	http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2004001000018	
Editor: 	Associação Brasileira de Divulgação Científica	
Relação: 	10.1590/S0100-879X2004001000018	
Formato: 	text/html	
Fonte: 	Brazilian Journal of Medical and Biological Research  v.37 n.10 2004	
Fonte: 	info:eu-repo/semantics/openAccess