AJP - Heart and Circulatory Physiology, Vol 249, Issue 5 995-1000, Copyright © 1985 by American Physiological Society
Coronary flow in heart-lung preparation affected by cardiopulmonary nerves and arterial PCO2
M. Kainuma, I. Ichimura, T. Shigei and N. Ishikawa
Studies on coronary vasodilator drugs utilizing heart-lung preparations
(HLP) have been disturbed by a spontaneous gradual increase in coronary
blood flow. With the purpose of finding out what would cause the gradual
increase, the time course of coronary sinus blood flow (CSBF) was
investigated in 20 dog HLPs under four experimental conditions, according
to whether cardiopulmonary nerves (CPN) were severed or not and whether CO2
content in the inspiratory gas was high (95% O2-5% CO2) or low (50% O2-50%
room air). The gradual increase in CSBF was observed, accompanied by a
significant increase in 6-ketoprostaglandin F1 alpha in the arterial blood,
only when CPN were intact and, simultaneously, inspiratory CO2 was high.
Nevertheless, the hemodynamic parameters, except CSBF, were almost similar
under four conditions. These results suggested that CSBF in HLP could be
affected via a synthesis and/or a release of prostaglandin I2 by the
interaction of CPN and arterial PCO2.
