Neutrophils increase histamine contractions in pig coronary artery: a role for lipoxygenase products.
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The possible role of neutrophils and the endothelium in the induction of hyperreactivity of the pig coronary artery to histamine was studied. In pig isolated coronary arteries histamine caused a concentration- dependent contraction; maximal contraction to histamine, however, was reduced in endothelium-denuded arteries. Pre-incubation of intact coronary arteries with isolated neutrophils did not affect the contractile response to histamine, while pre-incubation of endothelium- denuded arteries induced a hyperreactivity to histamine. This induction of hyperreactivity to histamine by neutrophils in pig coronary arteries seems to be mediated by lipoxygenase products, since it could be prevented by pre-incubation of the preparations with lipoxygenase inhibitors, but not with inhibitors of cyclo-oxygenase or with scavengers.