COLOCALIZATION OF NGF RECEPTOR WITH VIP IN RAT SUPRACHIASMATIC NEURONS

LOW-AFFINITY nerve growth factor receptor (p75NGFR) and vasoactive int estinal polypeptide (VIP) immunoreactive neuronal structures and their interrelationship were investigated at light and electron microscopic levels in rat suprachiasmatic nucleus (SCN). p75NGFR immunoreactive n euronal perikarya were detected in the ventrolateral part, while the d orsolateral region contained mainly receptor positive fibres. Double-l abel immunocytochemistry showed that nearly all p75NGFR positive neuro nes in the ventrolateral region of the SCN also contained VIP. The axo ns of the receptor positive neurones terminated on unidentified neuron es. In single-label experiments, the axons of the VIP containing neuro nes formed axodendritic synapses on cells containing the same peptide. The findings provide further insight on the chemical structural organ ization of the SCN.