INSTRUMENTATION OF RAMUS CIRCUMFLEXUS COMPROMISES THE INNERVATION OF CORONARY-ARTERY AND MYOCARDIUM

A fine non-compressing methacrylate ring was implanted on the ramus ci rcumflexus (RC) in 13 dogs. After the animals survived 7-14 days, the distribution and the rate of the Wallerian degeneration was studied in coronary arteries and myocardium by means of the formaldehyde induced fluorescence (FIF) technique and the transmission electron microscopy . The density of vasomotor innervation in the main arterial trunks was expressed as the number of transsected terminals per 1 mm(2) of the t ransversally sectioned media; the density of adrenergic terminals in t he myocardium was determined by the point-counting method. A compact s car encompassing the ring was found. The scar compressed some perivasc ular nerves. As a consequence, by about 40% of terminals degenerated i n the RC. The innervation of the branching of this artery was compromi sed as well. Moreover, the density of nerve terminals in myocardium de creased around the whole circumference of the ventricles and in the se ptum, equally by 29%. The value was lower than that found after the in strumentation of ramus interventricularis anterior (50%). The results indicate (i) a compromise of the innervation of coronary artery and my ocardium after the instrumentation of RC; (ii) the different decrease in density of nerve terminals in the myocardium suggests that majority of adrenergic nerve supply for ventricle myocardium is running along ramus interventricularis anterior.