Hypertension, Vol 7, 525-532, Copyright © 1985 by American Heart Association
S Kawashima and CS Liang
We studied the systemic and coronary hemodynamic effects of a new
antihypertensive agent, pinacidil, in nine morphine-sedated chronically
instrumented dogs with one-kidney renal hypertension and eight similarly
treated sham-operated normotensive dogs. The renal hypertensive dogs
exhibited higher mean aortic blood pressure, total peripheral vascular
resistance, and plasma renin activity before pinacidil administration than
the sham-operated animals. The renal hypertensive dogs also had a lower
left ventricular norepinephrine content, but the two groups did not differ
significantly in plasma norepinephrine levels, cardiac output, or heart
rate. Pinacidil decreased mean aortic pressure and total peripheral
vascular resistance and increased cardiac output and heart rate in both
groups. The changes in aortic pressure, total peripheral vascular
resistance, and cardiac output were similar between the two groups, but the
increase in heart rate was attenuated in renal hypertension. The peak rate
of rise of left ventricular pressure (dP/dt), the ratio of left ventricular
dP/dt and the developed pressure during isovolumic contraction (dP/dt/P),
myocardial oxygen consumption, and plasma norepinephrine levels increased
after pinacidil administration in the sham-operated dogs, but did not
change in the renal hypertension group. The two groups did not differ in
their responses of left ventricular dP/dt to intravenous isoproterenol.
Pinacidil also caused coronary vasodilation in both groups, as evidenced by
an increase in coronary blood flow and decreases in coronary vascular
resistance and myocardial oxygen extraction. The decrease in myocardial
oxygen extraction was similar in the two groups, but the increase in
coronary blood flow was significantly less (p less than 0.05), probably
because of the absence of an increase in myocardial oxygen consumption in
the renal hypertensive dogs.(ABSTRACT TRUNCATED AT 250 WORDS)
ARTICLES
Systemic and coronary hemodynamic effects of pinacidil in awake normotensive and hypertensive dogs
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