Journal of Applied Physiology, Vol 62, Issue 3 1124-1132, Copyright © 1987 by American Physiological Society
Effects of prostaglandin F2 alpha and prostacyclin on pulmonary microcirculation in the cat
K. Sada, M. Shirai and I. Ninomiya
In pulmonary microcirculation, using a new X-ray television system, we
measured the effects of prostaglandin F2 alpha (PGF2 alpha) and
prostacyclin on the internal diameter (ID), flow velocity, volume flow, and
transit times of a contrast medium in small arteries (Ta) and veins (Tv) in
anesthetized cats. The ID of the arteries and veins ranged from 100 to 500
micron. PGF2 alpha, 0.3, 1, and 3 micrograms/kg, predominantly decreased ID
on the arterial side in a dose-dependent manner but increased flow velocity
27-62%. Consequently, volume flow was kept relatively constant. With PGF2
alpha, Ta and Tv were decreased 18-41% and 4-15%, respectively.
Prostacyclin, 2 and 4 micrograms/kg, uniformly dilated the ID of small
arteries 9-16% but did not change small veins. With prostacyclin, flow
velocity was unchanged or decreased, whereas volume flow was increased
significantly, 27-32%. No significant changes of Ta and Tv were observed in
response to prostacyclin. When both prostaglandins, PGF2 alpha and
prostacyclin, were administered, they canceled each other with respect to
the ID of small pulmonary arteries. Prostacyclin also prevented the PGF2
alpha-induced vasoconstriction of the pulmonary venous microcirculation.
