Activation of GABAergic neurons following tooth pulp stimulation

The functional impact of gaba (3-aminobutyric acid)ergic neurons in nociceptive transmission of the spinal trigeminal nucleus is not fully established. using both the glutamic acid decarboxylase (gad)67-green fluorescence protein (gfp) knock-in mouse and the tooth pulp stimulation model,we performed double-immunofluorescent histochemistry to determine the characteristics of gabaergic neuron activation in the spinal trigeminal nucleus. the number of fos-positive gabaergic neuronal profiles was significantly increased 2 hrs after tooth pulp stimulation. the fos/gfp double-labeled neurons were mainly present in superficial laminae of the spinal trigeminal subnucleus interpolariscaudalis transition (vi/vc) and subnucleus caudalis (vc) on the side ipsilateral to the stimulation. subsequently,the number of double-labeled neurons decreased gradually and became comparable with that of the controls by 48 hrs. our results provide direct morphological evidence that a subset of gabaergic neurons in the spinal trigeminal system was activated during tooth pulp stimulation.