STRESSOR-SPECIFIC INCREASE OF VASOPRESSIN MESSENGER-RNA IN PARAVENTRICULAR HYPOPHYSIOTROPHIC NEURONS

Cellular levels of vasopressin (VP) and corticotropin-releasing factor (CRF) RNA transcripts were determined in hypophysiotrophic neurons af ter open-field and immobilization stress using quantitative in situ hy bridization. We found that 8 min open-field stress is sufficient to pr oduce a significant up-regulation of CRF mRNA, without any concomitant changes in the level of VP mRNA. In contrast, 8 min immobilization st ress resulted in an increased labeling density of both CRF and VP mRNA s. These results suggest that the level of CRF and VP transcripts in p arvicellular hypophysiotrophic neurons is differentially regulated in a stresser-specific manner.