| Research Abstract |
1) Immediate early genes (IEG) and peptide mRNAs following nociceptive stimulus
Following the injection of formaline into the lower pads or avulsion of sciatic nerve, we observed the c-fos and c-jun mRNAs in hypothalamus, spinal chord, and spinal ganglion. We observed the changes 1,8,24, and 48 hours following these experiments. In all regions examined, c-fos and c-jun mRNAs were increased after 1 and 2 hours later. In the hypothalamus, CRF,vasopressin and enkephalin mRNAs were increased following the injury. Since c-fos and vasopressin (or CRF) mRNAs were coexiswted, the change of peptide mRNA accompanies the expression of IEGs.
2) Induction of VGF following the nociceptive stimulus
Following the avulsion of sciatic nerve, we observed the induction of VGF,a NGF-inducible peptide, in the paraventricular nucleus of the hypothalamus. Since it is known that the induction of VGF represents the activity of neurons, the present result suggests the activity of hypothalamic paraventricular neurons increased after the nociceptive stimulus.
3) Rehydration prrocess from salt-loading
For examining the recovery process of stress, we examined the recovery of hypothalamic peptidergic neurons by the immunocytochemical method. We found that vasopressin and galanin returned to normal after 1 week of the rehydration, but dynorphin remained low even 1 week later. These findings suggests that the stress-induced endocrine change remains even after 1 week in the brain.
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