[Interaction of parasympathetic and sympathetic neurohumoral influences in regulating the heart rate of cod].

Chronotropic effects on the cod heart in case of the parasympathetic stimulation alone were initially negative and rather small; the joint stimulation of parasympathetic and sympathetic nerves or the vagus stimulation after noradrenaline administration augmented the initial bradycardia. In case of initial marked parasympathetic negative chronotropic effect, catecholamines diminished the parasympathetic inhibition. The sympathetic innervation and its transmitter seem to be able to increase the cholinergic effect.