抄録
When electrically stimulated, lingual nerve (LN) elicits a variety of responses mediated via parasympathetic reflex mechanismin the orofacial area. These include vasodilatation, salivation, lacrimation and mydriasis. We examined whether the trigeminal spinal nucleus (Vsp) forms part of the central mechanism by which electrical stimulation of the central cut end of the LN evokes parasympathetic reflex vasodilatation in the lower lip and mydriasis in artificially ventilated, cervically vago-sympathectomized cats deeply anesthetised with α-chloralose and urethane. Local anesthesia of Vsp by microinjection of lidocaine (reversible local anesthesia; 2%; 1 μl/site) reversibly and significantly reduced the ipsilateral-LN-evoked parasympathetic reflex vasodilatation and mydriasis. Unilateral microinjection of kainic acid (irreversible neurotoxic damage; 10 mM; 1 μ l/site) into Vsp ipsilateral to the stimulated LN led to an irreversible reduction in the reflex vasodilatation and mydriasis but had no effects on the vasodilatation and mydriasis elicited by stimulation of the contralateral LN. Electrical stimulation of Vsp elicited vasodilatation and mydriasis in an intensity- and frequency-dependent manner, regardless of whether systemic arterial blood pressure rose or fell. These results strongly suggest that Vsp is an important bulbar relay for LN-evoked parasympathetic reflex vasodilatation and mydriasis in the cat. [Jpn J Physiol 54 Suppl:S11 (2004)]
