CAT CEREBRAL-ARTERIES ARE FUNCTIONALLY INNERVATED BY SEROTONINERGIC FIBERS FROM CENTRAL AND PERIPHERAL ORIGINS

Background and Purpose Tryptophan hydroxylase activity and responses t o tyramine were analyzed in cat cerebral arteries to investigate serot oninergic innervation. Methods Enzymatic activity and responses to tyr amine were measured in vessels from animals subjected to cervical gang liectomy and dorsal and median raphe nuclei lesions. Results Tryptopha n hydroxylase activity in cat cerebral arteries was reduced after gang lia removal and raphe nuclei destruction. Contractile responses of the middle cerebral artery after gangliectomy were decreased by ketanseri ne. Dorsal raphe nucleus destruction had a significant effect on the c ontractile response, whereas median raphe nucleus destruction had only a slight effect. Conclusions Cat cerebral arteries receive serotonine rgic innervation from central and peripheral origins.