IN-SITU HYBRIDIZATION HISTOCHEMISTRY OF VGHM1F MESSENGER-RNA IN THE RAT SUPRACHIASMATIC NUCLEUS - COLOCALIZATION WITH VASOPRESSIN NEUROPHYSIN AND VIP-PHI

The expression of vgf gene, first isolated as a-gene induced by nerve growth factor in PC12 cells, was investigated in neurons of the suprac hiasmatic nucleus (SCN) by in situ hybridization. In the rat forebrain , the vgf mRNA was found most densely in the SCN. Neurons which expres s vgf mRNA were found both in the dorsomedial and ventrolateral subdiv isions. Double-labeling of vgf in situ hybridization and peptide immun ocytochemistry demonstrated that vgf mRNA was expressed in most vasopr essin- and neurophysin-immunoreactive neurons in the dorsomedial part and in vasoactive intestinal peptide (VIP)- and peptide histidine isol eucine amide (PHI)-immunoreactive neurons in the ventrolateral part. T hese findings suggest that vgf is a highly expressed gene in both vaso pressin/neurophysin neurons and VIP/PHI neurons which were speculated to be involved in the generation and entrainment of circadian rhythm.