[Enkephalin participation in the regulatory pattern of the vagus influence on cardiac rhythm in cats during the volley stimulation of the vagus nerve].

Effects of met-enkephalin and enkephalin analogue Tyr-D-Orn-Gly-Phe involved a depressing vagotropic action due to a selective decrease in the tonic component. The data obtained suggests different actions of met-enkephalin and its analogue upon the synchronizing component of vagal chronotropic action.