Previous studies have shown that CCK-8 has distinct antiopioid effect in the central sites related with pain control and blood pressure control. The aim of this study was to explore the receptor mechanism by which CCK...Previous studies have shown that CCK-8 has distinct antiopioid effect in the central sites related with pain control and blood pressure control. The aim of this study was to explore the receptor mechanism by which CCK-8 antagonized the depressor effect of u-and k-opioid agonists, and to observe whether CCK-8 could antagonize the depressor effect induced by muscimol, a nonopioid substance. The results showed that (ⅰ) The antagonistic effect of CCK-8 on opioid-induced hypotension could be blocked by intrathecal (i.t.) administration of CCK-B antagonist L-365, 260 at nanogram doses, or by CCK-A antagonist devazepide at doses 20—40 times higher than L-365, 260, indicating that it was the CCK-B receptor which mediates the antiopioid effect. (ⅱ) The depressor effect induced by intrathecal muscimol, a GABA agonist, was blocked neither by naloxone nor by CCK-8, supporting the notion that CCK-8 is an endogenous opioid antagonist rather thana universal anti-hypotension agent.展开更多
基金Project supported by the National Natural Science Foundation of China
文摘Previous studies have shown that CCK-8 has distinct antiopioid effect in the central sites related with pain control and blood pressure control. The aim of this study was to explore the receptor mechanism by which CCK-8 antagonized the depressor effect of u-and k-opioid agonists, and to observe whether CCK-8 could antagonize the depressor effect induced by muscimol, a nonopioid substance. The results showed that (ⅰ) The antagonistic effect of CCK-8 on opioid-induced hypotension could be blocked by intrathecal (i.t.) administration of CCK-B antagonist L-365, 260 at nanogram doses, or by CCK-A antagonist devazepide at doses 20—40 times higher than L-365, 260, indicating that it was the CCK-B receptor which mediates the antiopioid effect. (ⅱ) The depressor effect induced by intrathecal muscimol, a GABA agonist, was blocked neither by naloxone nor by CCK-8, supporting the notion that CCK-8 is an endogenous opioid antagonist rather thana universal anti-hypotension agent.
