Influence of intraventricularly applied apomorphine on somato-vegetative reflexes in cats.

To obtain information about the dopaminergic neurotransmission processes taking part in the somatovegetative reflexes the effects of intraventricularly given apomorphine were studied in lightly anaesthetized cats. The level of blood pressure and the reflexogenic hypertension due to central sciatic nerve stimulation were not changed when apomorphine was applied into the lateral and third but was inhibited when given into the fourth ventricle. The nictitating membrane contractions elicited by sciatic nerve stimulation were inhibited by apomorphine when introduced into each part of the ventricular system. Thus the inhibitory dopaminergic synapses located in the structures lining the walls of the brain ventricular system reached by apomorphine appear to be involved in the central control of somato-vegetative reflexes.