Cardiovascular effects of the new calcium antagonist isradipine and of diltiazem in anesthetized open-chest dogs.
Cardiovascular effects of the new calcium antagonist, isradipine (PN 200-110), were compared with those of diltiazem in anesthetized open-chest dogs. Isradipine 5 micrograms/kg i.v. produced significant decreases in systolic, diastolic and mean aortic blood pressure (AoP) concomitant with a decrease in mean renal blood flow (RBF) and increases in mean vertebral blood flow (VBF), mean coronary blood flow (CBF) and left ventricular dP/dt (LVdP/dt), but almost unchanged heart rate (HR) and left ventricular enddiastolic pressure (LVEDP). Diltiazem 300 micrograms/kg i.v. also produced decreases in AoP and RBF and increases in AoF, VBF and CBF. LVdP/dt and LVEDP were not significantly changed, but HR was decreased by this drug. Duration of increase in AoF, VBF and CBF was significantly longer in isradipine than in diltiazem. The decrease of coronary vascular resistance relative to total peripheral resistance was significantly greater than 1.0 for diltiazem, but not for isradipine. Results indicate that isradipine produces effects on AoP, AoF, VBF, CBF, RBF and LVEDP similar to diltiazem and the drug increases LVdP/dt without a decrease in HR in contrast to diltiazem, and that the effects of isradipine were long sustained when compared with those of diltiazem.
Sakanashi
M
M
Department of Pharmacology, School of Medicine, Faculty of Medicine, University of the Ryukyus, Okinawa, Japan.
Miyamoto
Y
Y
Noguchi
K
K
Kato
T
T
Matsuzaki
T
T
Miyagi
H
H
Ikema
S
S
Kinjo
N
N
D000758:Anesthesia; D000818:Animals; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D003326:Coronary Circulation / Q000187:drug effects; D004110:Diltiazem / Q000494:pharmacology*; D004285:Dogs; D005260:Female; D006439:Hemodynamics / Q000187:drug effects*; D017275:Isradipine; D008297:Male; D011725:Pyridines / Q000494:pharmacology*; D012039:Regional Blood Flow / Q000187:drug effects; D013997:Time Factors; D014655:Vascular Resistance / Q000187:drug effects
D002121:Calcium Channel Blockers; D011725:Pyridines; D004110:Diltiazem; D017275:Isradipine