THE MEDIAL NUCLEUS OF THE SOLITARY TRACT MEDIATES THE TRIGEMINALLY EVOKED PRESSOR-RESPONSE

THE present study examined whether the nucleus of the solitary tract ( NTS) plays a role in mediating the trigeminally evoked presser respons e which occurs after noxious perturbation of the nasal mucosa or elect rical stimulation of the ethmoidal nerve (EN5). We recorded arterial b lood pressure responses to EN5 stimulations before and after injection s of the calcium channel blocker CoCl2 into the NTS. Unilateral and bi lateral injections of CoCl2 into the medial NTS resulted in significan t blockade (p < 0.05 and p < 0.01, respectively) of the EN5-evoked pre sser responses. Recovery of the presser responses was observed 15-25 m in after the CoCl2 injections. CoCl2 injections into the caudal commis sural NTS remained largely ineffective with respect to blocking the EN 5-evoked presser responses. These findings strongly suggest that the m edial NTS is a crucial link for the trigeminally induced presser respo nse. (C) 1998 Rapid Science Ltd.