Data/hora: 04/06/2024 00:36:31

Provedor de dados: 	56	
País: 	Brazil	
Título: 	Participation of ATP-sensitive K+ channels in the peripheral antinociceptive effect of fentanyl in rats	
Autores: 	Rodrigues,A.R.A.; Castro,M.S.A.; Francischi,J.N.; Perez,A.C.; Duarte,I.D.G.	
Data: 	2005-01-01	
Ano: 	2005	
Palavras-chave: 	Peripheral antinociception; Fentanyl; K+ channel; Μ-Opioid receptor agonist; Glibenclamide.	
Resumo: 	We examined the effect of several K+ channel blockers such as glibenclamide, tolbutamide, charybdotoxin (ChTX), apamin, tetraethylammonium chloride (TEA), 4-aminopyridine (4-AP), and cesium on the ability of fentanyl, a clinically used selective µ-opioid receptor agonist, to promote peripheral antinociception. Antinociception was measured by the paw pressure test in male Wistar rats weighing 180-250 g (N = 5 animals per group). Carrageenan (250 µg/paw) decreased the threshold of responsiveness to noxious pressure (delta = 188.1 ± 5.3 g). This mechanical hyperalgesia was reduced by fentanyl (0.5, 1.5 and 3 µg/paw) in a peripherally mediated and dose-dependent fashion (17.3, 45.3 and 62.6%, respectively). The selective blockers of ATP-sensitive K+ channels glibenclamide (40, 80 and 160 µg/paw) and tolbutamide (80, 160 and 240 µg/paw) dose dependently antagonized the antinociception induced by fentanyl (1.5 µg/paw). In contrast, the effect of fentanyl was unaffected by the large conductance Ca2+-activated K+ channel blocker ChTX (2 µg/paw), the small conductance Ca2+-activated K+ channel blocker apamin (10 µg/paw), or the non-specific K+ channel blocker TEA (150 µg/paw), 4-AP (50 µg/paw), and cesium (250 µg/paw). These results extend previously reported data on the peripheral analgesic effect of morphine and fentanyl, suggesting for the first time that the peripheral µ-opioid receptor-mediated antinociceptive effect of fentanyl depends on activation of ATP-sensitive, but not other, K+ channels.	
Tipo: 	Info:eu-repo/semantics/article	
Idioma: 	Inglês	
Identificador: 	http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2005000100014	
Editor: 	Associação Brasileira de Divulgação Científica	
Relação: 	10.1590/S0100-879X2005000100014	
Formato: 	text/html	
Fonte: 	Brazilian Journal of Medical and Biological Research  v.38 n.1 2005	
Fonte: 	info:eu-repo/semantics/openAccess