Differential effects of forced swim-stress on the corticotropin-releasing hormone and vasopressin gene transcription in the parvocellular division of the paraventricular nucleus of rat hypothalamus

Corticotropin-releasing hormone (CRH) and vasopressin (AVP) colocalize in the parvocellular division of the paraventricular nucleus of the hypothalamus (PVN). We examined the effect of forced swim-stress on the CRH and AVP primary transcript (hnRNA) levels in the rat PVN by semi-quantitative in situ hybridization. CRH hnRNA increased markedly following 10-min swim-stress and returned to the basal level by 2 It. AVP hnRNA in the parvocellular division of the PVN, where AVP colocalizes with CRH, did not change significantly immediately after the swim-stress, but it did increase significantly 2 h after the stress. Pretreatment with dexamethasone abolished the increases in CRH and AVP hnRNA levels after the swim-stress. The present results demonstrate the differential effects of forced swim-stress on the CRH and AVP gene transcription in the parvocellular PVN, confirming the diverse response of the dual peptide-containing system in the face of acute stressful events. (C) 2004 Elsevier Ireland Ltd. All rights reserved.