CONNECTIONS BETWEEN GABA-OR GLYCINE-IMMUNOREACTIVE TERMINALS AND Fos-POSITIVE PROJECTION NEURONS IN THE RAT MEDULLARY DORSAL HORN / 解剖学报

ABSTRACT

Objective To investigate the connections between ?\|aminobutyric acid(GABA)\|or glycine (Gly)\|containing terminals and Fos\|positive projection neurons from the medullary dorsal horn (MDH) to the thalamus or parabrachial nuclei(PBN). Methods Tetramethyl rhodamine(TMR) retrograde tracing,combined with immunofluorescence histochemical triple\|staining for TMR/Fos/GABA or TMR/Fos/Gly was used. Results GABA\|or Gly\|immunoreactive terminals were chiefly located in the superficial laminae(laminae Ⅰ and Ⅱ) of the MDH.After orofacial noxious stimulation.Fos\|positive neurons were also mainly observed in the superficial laminae.After injecting TMR into the unilateral thalamus or PBN,TMR retrogradely labeled neurons were mainly distributed in the superficial laminae of the controlateral or ipsilateral MDH,respectively.Some of these TMR\|labeled neurons also exhibited Fos\|immunoreactivities.GABA\| or Gly\|containing terminals made close contacts with Fos positive retrogradely labeled neurons.Conclusion\ In the superficial laminae of the MDH,some of the orofacial nociceptive neurons send project fibers directly to the thalamus or PBN,GABA and Gly might exert their inhibitory effects on these nociceptive projection neurons.\;[