Effect of chronic cigarette smoke exposure on pulmonary vasomotion in beagle dogs

Abstract

To study the effect of chronic cigarette smoke exposure on the resistive properties of the pulmonary vasculature, left lower lobes from 12 control beagles and 6 beagles who had smoked cigarettes (50 cigarettes/wk for 40 wk) were perfused in situ to measure the vascular pressure-flow relationship and the resistance of the three vascular segments with the arterial and venous occlusion technique. In control subjects the vascular resistance in the arterial, middle, and venous segments was 23, 36, and 41% of the total, respectively. The segmental distribution of vascular resistance was not significantly different in the cigarette smoke-exposed dogs, despite the fact that the absolute values were 30-40% less than that of the control group. The longitudinal distribution of resistance among the three vascular segments and their response to drugs were different in beagles than was previously found in mongrels. In all beagles the veins were considerably more reactive than arteries. Vasoconstriction with serotonin (5-HT) prostaglandin F2 alpha (PGF2 alpha), norepinephrine, histamine, and methacholine (M) infusion occurred predominantly in the veins. The effect of PGF2 alpha and 5-HT was totally different than that previously observed in mongrels in which the constriction was predominantly in the arteries. Chronic cigarette smoking reduced the basal pulmonary vascular resistance and attenuated the venoconstrictor response to 5-HT and M but potentiated the hypoxic pressor response of the microvessels.

Identification of Constriction in Large versus Small Vessels using the Arterial-Venous and the Double-Occlusion Techniques in Isolated Canine Lungs

“…Although the site of vasocon striction with PGF2" was different than previously reported [6,12], the effects of serotonin, histamine and norepinephrine were similar in both studies. In another study we found that the effects of sero tonin were different in beagles than in mongrel dogs: In beagles, serotonin con stricted the pulmonary veins markedly [16], whereas, as demonstrated in the pres ent study (in mongrels), serotonin con stricted only the arteries. Thus in view of these different experimental results pro duced by the same investigator using the same techniques, it is reasonable to sug gest that contradiction in experimental re sults from different laboratories [2,6,12,17,18] on the effect of vasoactive sub stances in the same species as well as on different species are likely to be real rather than due to technical differences.…”

Cardiopulmonary Effects of a Brief Exposure to Cigarette Smoke in the Guinea Pig

“…They found no effect at control pO?, but the smoke produced vasodilation during hypoxia. In contrast, Hakim et al [11] found that smoke reduced the basal vascular resistance but potentiated the hypoxic pres sor response.…”

“…In general, al though a bronchospastic response to cigarette smoke has been found [6][7][8], a possible linkage of the bron chospastic to a vasospastic response to cigarette smoke has not, to our knowledge, been investigated. A cardiovascular reaction is postulated because of cir culating mediators such as eicosanoids which are known to be altered by cigarette smoke inhalation [9], but investigations of this response have shown con flicting results [10][11][12], In this study, using the guinea pig model of cigarette smoke-associated emphysema, we were able to examine both the bronchospastic and vasospastic response to an acute exposure to cigarette smoke at the same time, and in the same animal. We could therefore examine the association of both of these effects with the inflammatory reaction produced by the smoke.…”