Effect of nicardipine and BAY K-8644 on the pressor responses to afferent nervous stimulation in dogs.
The effects of nicardipine on the pressor responses elicited by afferent vagal stimulation were investigated in urethane-anesthetized dogs. Nicardipine (100 micrograms/kg i.v.) decreased the rise in blood pressure observed after a 10, 20 and 30 Hz stimulation during 15 sec. The pressor response to 5 Hz stimulation was changed into a depressor response after nicardipine. After BAY K-8644 (100 micrograms/kg i.v.), deprived of any effect alone, nicardipine always exhibited a reduction in these pressor responses. Since these cardiovascular responses observed after afferent vagal stimulation are related to an increase in sympathetic tone, these results suggest that nicardipine, besides having calcium channel blocking properties, also exerts an inhibitory effect on the release of noradrenaline from sympathetic nerves.
Estan
L
L
Laboratoire de Pharmacologie Médicale et Clinique, INSERM U317, Faculté de Médecine, Toulouse, France.
Montastruc
J L
JL
Montastruc
P
P
D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester / Q000494:pharmacology*; D000758:Anesthesia; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D004285:Dogs; D004558:Electric Stimulation; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D008297:Male; D009475:Neurons, Afferent / Q000187:drug effects*; D009529:Nicardipine / Q000494:pharmacology*
D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester; D009529:Nicardipine