Biology of Reproduction, Vol 21, 229-233, Copyright © 1979 by Society for the Study of Reproduction

Effect of Nicotine on Uterine Blood Flow in Anesthetized Pregnant Rats

¹ Department of Anatomy and Human Biology, The University of Western Australia, Nedlands, Western Australia 6009

A venous outflow technique was developed to examine the influence of nicotine on uterine blood flow (UBF) in anesthetized rats at Days l6 or 22 of gestation; term is Day 23. Nicotine was infused i.v. for 5 min periods at the rate of 1, 10 or 100 µg/min which adjusted for body weight is about 1, 10 or 100 times the rate absorbed during cigarette smoking in humans. The results at Days 16 and 22 were similar. Nicotine at the 2 lower infusion rates had little or only transitory effects on arterial pressure, pulse rate and UBF. At the highest infusion rate, however, there was a pronounced rise then fall in arterial pressure, uterine vascular resistance increased and UBF fell precipitously to about 51% (Day 16) and 70% (Day 22) of pretreatment values. It seems that nicotine can restrict UBF in the anesthetized pregnant rat but only at levels greatly exceeding the equivalent of those reached during cigarette smoking.

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ACKNOWLEDGMENTS This work was supported by a grant from the Australian Tobacco Research Foundation. We are grateful for the help of Mr. W. Arnell and Misses G. Fyfe and A. Wong.