beta-Endorphin-like immunoreactivity in the brain of the lizard, Lacerta muralis

Using immunocytochemical methods, a beta-endorphin-like immunoreactive substance was identified in the brain of the lizard Lacerta muralis. beta-Endorphin-like neurons were observed in the dorsal posterior part of the paraventricular nucleus and in the caudal region of the nucleus ventromedialis hypothalami. beta-Endorphin-like immunoreactive fibers were also detected in the median eminence. Another cell group displaying beta-endorphin-like immunoreactivity was found in both subdivisions of the oculomotor nucleus and in the periaqueductal gray of the mesencephalon. In addition, a beta-endorphin-like immunoreaction was observed in the perikarya of the Purkinje cells and in their axonal processes. These patterns of immunoreactivity were completely abolished when a specific antiserum was absorbed with its corresponding antigen or with beta-lipotropin. These control tests suggest that the immunoreaction might correspond to a beta-endorphin- or lipotropin-like reaction. The results are discussed in relation to the possibility that a beta-endorphin-like peptide may be involved in hypophysial regulation or neuromodulator activity in the brain of the lizard L. muralis.