Interruption of sympathetic and vagal-mediated afferent responses by transmural myocardial infarction.

We have demonstrated previously that sympathetic and vagal afferents travel in an apical-to-basal course in the heart, and can be stimulated selectively with epicardial applications of bradykinin and nicotine, respectively. In this study we tested the hypothesis that transmural myocardial infarction interrupts sympathetic and vagal afferent fibers traveling through the infarction and produces regions of afferent denervation in areas apical to the infarction. In open-chest, chloralose-anesthetized dogs, transmural myocardial infarction was created by embolizing a diagonal branch of the left anterior descending coronary artery with a vinyl latex solution that was injected directly into the artery and hardened rapidly. The transmural nature of the infarction was verified by the nitro blue tetrazolium staining technique for dehydrogenase enzymes. Epicardial applications of bradykinin (5 micrograms) and nicotine (50 micrograms) were used to stimulate chemically sensitive sympathetic and vagal afferent nerve en...