[Efferent projections of "classical" peptidergic neurons of the neurosecretory system of the telencephalon in reptiles (Scincus scincus L. and Chalcides ocellatus Forskal; Lacertilia, Squamata].

In both species of lacertilian reptiles investigated, the peptidergic hypothalamic supraoptic and paraventricular nucleus project with efferents to the telencephalon, to caudal parts of the brain, and to the spinal cord. The marked system of efferents of the "classic" peptidergic neurosecretory nuclei to the telencephalon was mapped. The unlabeled peroxidase-antiperoxidase immunocytochemical procedure revealed at the light microscopical level neurophysin- respectively mesotocin- or vasotocin-containing exohypothalamic fibres in the septal area, in subcortical regions (ventral striatum and hypopallium), and in all layers of the cortical areas (medial, dorsal and lateral cortex). Within the different parts of the brain, there seems to be a characteristically quantitative ratio of the mesotocin and vasotocin fibres. The terminals of the exohypothalamic fibres contact perikarya and processes of neurons of the target regions intimately. In a selected area, peptidergic synapses could be demonstrated at the electron microscopical level using an ultrahistochemical method. It is assumed that the nonapeptides mentioned are released from the fibre terminals and then act as neurotransmitters/neuromodulators influencing different brain functions.