A comparison of the haemodynamic profiles of Ro 31-6930, cromakalim and nifedipine in anaesthetised normotensive rats.
The regional haemodynamic profiles of Ro 31-6930, cromakalim and nifedipine were compared using pulsed Doppler flowmetry in the anaesthetised rat. In order of potency, Ro 31-6930 (0.1-300 micrograms/kg), cromakalim (1-300 micrograms/kg) and nifedipine (1-1000 micrograms/kg) produced dose related falls in mean arterial pressure. The hypotensive effects of Ro 31-6930 and cromakalim were accompanied by reflex tachycardia. All three agents reduced renal vascular resistance by 30-50%. Cromakalim exerted a selective action on this vascular bed. Similar maximal reductions in mesenteric vascular resistance (37-50%) were observed; however, cromakalim was the least potent on this vascular bed. Maximal reductions in iliac vascular resistance (65-78%) were observed, with an order of potency as observed on mean arterial pressure. Qualitative differences in the regional haemodynamic profiles of Ro 31-6930, cromakalim and nifedipine are evident from this study. The different profiles of Ro 31-6930 and cromakalim may reflect structural differences between the pharmacophores of these compounds.
Duty
S
S
Department of Physiological Sciences, University of Manchester, Medical School, U.K.
Paciorek
P M
PM
Waterfall
J F
JF
Weston
A H
AH
D000758:Anesthesia; D000818:Animals; D000959:Antihypertensive Agents / Q000494:pharmacology*; D001578:Benzopyrans / Q000494:pharmacology*; D001794:Blood Pressure / Q000187:drug effects; D019806:Cromakalim; D006339:Heart Rate / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects*; D007083:Iliac Artery / Q000187:drug effects; D008297:Male; D009543:Nifedipine / Q000494:pharmacology*; D011725:Pyridines / Q000494:pharmacology*; D011758:Pyrroles / Q000494:pharmacology*; D051381:Rats; D012039:Regional Blood Flow / Q000187:drug effects; D012079:Renal Circulation / Q000187:drug effects; D013152:Splanchnic Circulation / Q000187:drug effects; D014655:Vascular Resistance / Q000187:drug effects
D000959:Antihypertensive Agents; D001578:Benzopyrans; D011725:Pyridines; D011758:Pyrroles; D019806:Cromakalim; C062764:Ro 31-6930; D009543:Nifedipine