Possible opioid participation in the analgesic effects of the renin-angiotensin system.
Using the tail-flick method in 45 rats with a chronic cannula stereotaxically implanted in the third ventricle, a rapid onset, dose related and short lasting analgesia was obtained after intracerebroventricular injection of Ang II 10-15 ng/kg or renin 0.03-0.1 U. Analgesic effects of the endogenous and exogenous Ang II are prevented by naloxone--1 mg/kg i.p. The inhibition of serotonin synthesis with PCPA--400 mg/kg/day i.p. for five days as well as the serotonin-receptor block with ketanserin 0.1 mg/kg i.p. partially prevent analgesic effects of Ang II and renin intracerebral administration. The increase of the pain perception threshold after infusing into the brain Ang II or renin points out a new functional consequence of the possible opioid participation in the central effects of renin-angiotensin system.
D000803:Angiotensin I / Q000494:pharmacology*; D000804:Angiotensin II / Q000494:pharmacology*; D000809:Angiotensins / Q000494:pharmacology*; D000818:Animals; D004723:Endorphins / Q000494:pharmacology*; D009270:Naloxone / Q000494:pharmacology*; D051381:Rats; D012084:Renin-Angiotensin System / Q000187:drug effects*; D012702:Serotonin Antagonists / Q000494:pharmacology*
D000809:Angiotensins; D004723:Endorphins; D012702:Serotonin Antagonists; D000804:Angiotensin II; D009270:Naloxone; D000803:Angiotensin I