DISTRIBUTION OF FMRFAMIDE-LIKE IMMUNOREACTIVITY IN THE BRAIN OF THE LIZARD PODARCIS-SICULA

The distribution of FMRFamide-like immunoreactive peptides was investi gated in the brain of the lizard, Podarcis sicula, using the indirect immunofluorescence technique. The main populations of FMRFamide-immuno reactive cell bodies were located in the forebrain. In the telencephal on, FMRFamide-containing neurons were found both in the pallium and su bpallium, namely in the medial cortex, the anterior olfactory nucleus, the nucleus accumbens, the septal nuclei, the nucleus of the medial f orebrain bundle, and the nucleus of the diagonal band of Broca. In the diencephalon, a dense accumulation of FMRFamide-immunoreactive neuron s was observed in the area preoptica lateralis, the nucleus suprachias maticus, the nucleus periventricularis hypothalami, the area lateralis hypothalami, and the dorsal region of the nucleus geniculatus lateral is. In the midbrain, sparse immunoreactive perikarya were found in the tegmentum of the mesencephalon. FMRFamide-immunoreactive fibers were visualized in all regions containing positive cell bodies. In particul ar, dense bundles of immunoreactive processes were seen in the area pr eoptica lateralis, in the hypothalamus, and in the median eminence. Th e tectum and the basal mesencephalon were also densely innervated. Con versely, the caudal brain stem only exhibited scarce immunoreactive pr ocesses. The distribution pattern of FMRFamide-immunoreactive neurons in the brain of Podarcis sicula exhibits a number of similarities with that reported in mammals, but significantly differs from that reporte d in amphibians and fish, suggesting that the neuromodulatory function s of FMRFamide may have diverged during the emergence of terrestrial l ife.