抄録
[Objectives] The aim of the present study was to elucidate the functional role of the paratrigeminal nucleus (Pa5) neurons in trigeminal pain and autonomic system.
[Methods] <Immunohistochemical study> The left vagal nerve was transected and Complete Freund's adjuvant (CFA) was injection into the left temporlomandibular joint (TMJ) at 2 days after injection of Fluorogold (FG) into the left parabrachial nucleus (PBN). The rats were anesthetized with sodium pentobarbital and perfused at 3 days after CFA injection. The effect of vagal nerve transection on the expression of Fos and/or FG-labeled neurons in the PBN and Pa5 was studied.<Electrophysiological study> The single neuronal activities were recorded from the Pa5 responsive to noxious stimulation of the face. The single neurons were classified as WDR and NS neurons. In addition, the effect of vagal or sympathetic nerve stimulation on the Pa5 neuronal activities was precisely analyzed.
[Results] A large number of Fos protein-like immunoreactive cells were expressed in the bilateral Pa5. The Fos/FG double-labeled neurons were increased in the ipsilateral Pa5 after the vagal nerve transection. A number of nociceptive neurons in Pa5 was modulated by electrical stimulation of the vagal or sympathetic nerve stimulation.
[Conclusions] These findings suggest that the Pa5 neurons would be involved in the transmission of the trigeminal nociceptive information to the Pa5 neurons in correlation with autonomic function. [Jpn J Physiol 54 Suppl:S172 (2004)]
