CONNECTIONS BETWEEN GAD-LIKE IMMUNOREACTIVE TERMINALS AND COEXISTENT POSITIVE NEURONS OF PAG-AND GABA-A-RECEPTOR ?3-LIKE IN THE MESENCEPHALIC TRIGEMINAL NUCLEUS OF THE RAT / 解剖学报

ABSTRACT

Objective To observe the connections between the glutamic acid decarboxylase\|like immunoreactive(GAD\|LI) axonal terminals and the positive neurons showing phosphate actived glutaminase(PAG)\|LI or GABA\-A\|receptor ?3 subunit (GABA\-AR?3)\|LI and parvalbumin(PV)\|LI in the mesencephalic trigeminal nucleus(Vme) of the rat. Methods The triple\|immunofluoresence histochemical staining techniques were used in the present study,and stained sections were observed under a confocal laser\|scanning microscope. Results Many neuronal cell bodies through the whole rostrocaudal extent of Vme were showed dense GABA\-AR?3\|,PAG\| and PV\|like immunoreactivities,respectively.The majority of them were large pseudounipolar neurons(diameter 25\|50?m).About 90% of PAG\|LI neurons expressed both GABA\-AR?3\|LI and PV\|LI.Confocal laser\|scanning microscope further revealed that dense GAD\|LI axonal varicosities were found to surround the somata of Vme neurons showing both GABA\-AR?3\| and PAG\|like immunoreactivities,and formed the close contact each other.Conclusion\ The present results suggested that the GABAergic axonal terminals projecting to Vme might exert inhibitory regulation and control effect through GABA\-AR?3 subunit localizated in somata of Vme neurons on the transmission of orofacial region proprioceptive sensory information mediated by glutamate.