Involvement of cholinergic mechanisms in the central cardiovascular actions of nicardipine in dogs.
The involvement of cholinergic mechanisms in the central cardiovascular effects of a dihydropyridine, nicardipine, was investigated in pentobarbital-anaesthetized normotensive dogs. Nicardipine (1 microgram/kg) injected intracisternally (i.c.) induced a rise in both blood pressure and heart rate. This induced hypertension was suppressed by pretreatment with intravenous (i.v.) atropine or i.c. methylatropine but not i.v. methylatropine. I.c. methylatropine reduced nicardipine-induced tachycardia. These results demonstrate the involvement of cholinergic pathways in the central cardiovascular effects of i.c. nicardipine in dogs and suggest a functional interaction between dihydropyridine binding sites and cardiovascular cholinergic mechanisms in the brain.
Laboratoire de Pharmacologie Médicale et Clinique, UA 644 du CNRS, Faculté de Médecine, Toulouse, France.
J L
JL
Montastruc
L
L
Dang Tran
A M
AM
Huchet-Brisac
J
J
Chelly
M
M
Rostin
P
P
Montastruc
D000818:Animals; D001285:Atropine / Q000494:pharmacology; D001286:Atropine Derivatives / Q000494:pharmacology; D001794:Blood Pressure / Q000187:drug effects; D001921:Brain / Q000187:drug effects; D002319:Cardiovascular System / Q000294:innervation*; D004285:Dogs; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects*; D007276:Injections, Intraventricular; D008297:Male; D009529:Nicardipine / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D011950:Receptors, Cholinergic / Q000187:drug effects*
D001286:Atropine Derivatives; D011950:Receptors, Cholinergic; D001285:Atropine; C006649:methylatropine; D009529:Nicardipine