COMPARATIVE EFFECTS OF LINGUAL AND FACIAL-NERVE STIMULATION ON INTRACRANIAL AND EXTRACRANIAL VASOMOTOR RESPONSES IN ANESTHETIZED CATS

Electrical stimulaion of the central cut end of the lingual nerve (as reflex activation of parasympathetic nerve) or of the peripheral cut e nd of the facial (VIIth cranial) nerve (as direct activation of parasy mpathetic nerve) elicited the ipsilateral blood flow increases in lowe r lip, palate and common carotid artery (CCA) but not in frontal cereb ral cortex in alpha-chloralose-urethane anesthetized, vago-sympathecto mized cats. No significant difference, in terms of the vasomotor chang es examined, was found between lingual nerve and facial nerve stimulat ion. The results suggest that there is no somato-parasympathetic refle x vasodilator mechanism serving the frontal cerebral cortex, and that changes in CCA blood flow should not be taken to be indicative of bloo d flow changes in cerebrocortical blood flow. However, me cannot entir ely rule out the possibility of a neurogenic vasodilator influence of the facial pathway, since small blood flow increases in the frontal ce rebral cortex mere sometimes observed on facial nerve stimulation. (C) 1997 Tohoku University Medical Press.