Journal of Applied Physiology, Vol 68, Issue 1 248-252, Copyright © 1990 by American Physiological Society
Time-dependent changes in cardiovascular regulation caused by chronic tobacco smoke exposure
C. H. Bennett and D. R. Richardson
Department of Biology, Kentucky State University, Frankfort 40601.
The purpose of this study was to determine whether chronic tobacco smoke
exposure for less than 2 mo alters cardiovascular regulation. One group of
male Sprague-Dawley rats was administered tobacco smoke from low-nicotine
cigarettes (group A, 1 mg/cigarette) for 4-6 wk, while a second group (B)
served as a sham control by receiving only puffs of room air. Reflex
adjustments in mean arterial blood pressure (MAP) after bilateral common
carotid occlusion (BCCO) were compared between the two groups. In the
anesthetized control state, no significant difference existed for the
cardiovascular parameters measured in the two groups. However, MAP
increases after BCCO were significantly greater in the smoke-treated
animals (P less than 0.05) compared with the sham-treated group. At 10, 20,
30, and 40 s after BCCO, MAP increases above preocclusion values were 66,
45, 42, and 38% for group A and 35, 26, 24, and 22% for group B,
respectively. Additionally, the time required to reach maximum MAP after
BCCO was significantly less (P less than 0.05) for the smoke-treated vs.
sham-treated animals (8.5 +/- 0.2s for group A, 11.2 +/- 0.3s for group B).
MAP changes during BCCO were significantly different (P less than 0.05)
between the treatment groups after cervical vagotomy. It is concluded that
chronic tobacco smoke exposure in experimental animals for periods as short
as 4-6 wk alters the reflex regulation of the cardiovascular system.
