Histochemical studies of the relationship of chromaffin cells and adrenergic nerve fibers to cardiac ganglia of several species

JAcoBowITz, DAVID: Histochemical studies of the relationship of chromaffin cells and ad-renergic nerve fibers to the cardiac ganglia of several species. J. Pharmacol. Exp. Therap. 158: 227-240, 1967. Atrial cardiac ganglia of rats, cats, guinea pigs and mice were studied for catecholamine-containing structures by a histochemical fluorescence method. Very fine varicose adrenergic fibers were seen in close apposition to some of the cholinergic ganglion cells. The administration of a monoamine oxidase inhibitor followed by 3,4-dihydroxy-phenylalan.ine resulted in the appearance of catecholamine (CA) fluorescence in some ganglion cells. This suggests that at least some parasympathetic cells are capable of tak-ing up 3,4-dihydroxyphenylalamne and synthesizing and metabolizing CA. Intense CA-fluorescent cells resembling adrenal medullary cells were found in the confines of the atrial ganglia of all species. Positive chroman and silver-staining reactions were observed in these cells of the cat atria. The cells are considered to be chromaffin cells and as such can be regarded as an extraneuronal CA pool. One dose of reserpine (5 mg/kg) administered 24 or 4 hr before sacrifice does not appear to affect the CA content of the chromaffin cells