Centrally mediated cardiovascular effects of nicergoline in the dog compared to those of clonidine.
The intracisternal administration of nicergoline (5 micrograms/kg) or clonidine (4 micrograms/kg) in chloralose-anesthetized dogs induced significant decreases in blood pressure and heart rate. The same dose of nicergoline induced similar effects on atropine-pretreated dogs. Guanethidine pretreatment (30 mg/kg i.v. the day before) prevented the hypotension but not the bradycardia induced by clonidine. Guanethidine prevented both the hypotension and the bradycardia induced by nicergoline. Thus, nicergoline, unlike clonidine, does not increase cardiac parasympathetic activity. When administered by the same route at the same doses, nicergoline did not change the slope and reduced the amplitude whereas clonidine increased both the slope and the amplitude of the heart period vs. blood pressure curve obtained by intravenous administration of phenylephrine. Taken together, these results suggest that nicergoline and clonidine probably act on different structures within the central nervous system.
D000818:Animals; D001285:Atropine / Q000494:pharmacology; D001794:Blood Pressure / Q000187:drug effects; D003000:Clonidine / Q000494:pharmacology*; D004285:Dogs; D004873:Ergolines / Q000494:pharmacology*; D005260:Female; D006145:Guanethidine / Q000494:pharmacology; D006339:Heart Rate / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects*; D008297:Male; D009530:Nicergoline / Q000494:pharmacology*; D010275:Parasympathetic Nervous System / Q000187:drug effects; D010656:Phenylephrine / Q000494:pharmacology; D011311:Pressoreceptors / Q000187:drug effects; D012018:Reflex / Q000187:drug effects; D013997:Time Factors
D004873:Ergolines; D010656:Phenylephrine; D001285:Atropine; D009530:Nicergoline; D003000:Clonidine; D006145:Guanethidine