The parasympathetic neuroeffector junction of the heart.

This review has directed attention to the anatomical, biochemical, physiological, and pharmacological features of cardiac parasympathetic neuroeffector transmission. The relationships among these properties have permitted a synthesis of the operation of the parasympathetic nervous system at the subcellular, cellular, tissue, and organ level in the heart. However, the attempt to obtain a comprehensive model of parasympathetic neuroeffector transmission in the heart has not only unmasked many features of junctional activity that are poorly understood, but also indicated significant gaps between in vitro and in vivo experimental situations.