Endogenous opiate system and dihydropyridine-induced central regulation of sympathetic tone in rats.
Intracerebroventricular injections of nicardipine (10 micrograms/kg) to SHR induced hypotension which was suppressed by pretreatment with 6-OHDA. This hypotension was also inhibited by a previous injection of naloxone (100 micrograms/kg i.c.v.) whereas the hypotension induced by intravenously injected nicardipine (10 micrograms/kg) was not changed. It is suggested that the release of endogenous opioids is involved in the sympatho-inhibitory effect of centrally administered dihydropyridine calcium channel antagonists.
Champeroux
P
P
Centre de Recherches Biologiques, Baugy, France.
Brisac
A M
AM
Laurent
S
S
Schmitt
H
H
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D004095:Dihydropyridines / Q000494:pharmacology*; D004723:Endorphins / Q000502:physiology*; D006892:Hydroxydopamines / Q000494:pharmacology; D007022:Hypotension / Q000139:chemically induced; D008297:Male; D009270:Naloxone / Q000494:pharmacology; D009529:Nicardipine / Q000494:pharmacology; D016627:Oxidopamine; D051381:Rats; D011918:Rats, Inbred SHR; D011957:Receptors, Opioid / Q000187:drug effects / Q000502:physiology; D013564:Sympathetic Nervous System / Q000187:drug effects / Q000502:physiology
D004095:Dihydropyridines; D004723:Endorphins; D006892:Hydroxydopamines; D011957:Receptors, Opioid; D009270:Naloxone; C038806:1,4-dihydropyridine; D016627:Oxidopamine; D009529:Nicardipine