EVIDENCE FOR COEXISTENCE OF CCK-8 AND GNRH IN NEURONS OF THE MESENCEPHALIC TEGMENTUM IN THE CHAMELEON

A double-label immunofluorescence technique was used to demonstrate th e co-localization of cholecystokinin-8 (CCK-8) and gonadotrophin-relea sing hormone (GnRH) in individual neurons and processes of the chamele on brain. Go-localization was limited to a small population of cells i n the dorsomedial tegmentum; in other regions of the brain, neurons we re observed to be either CCK-8-immunopositive or GnRH-immunopositive b ut never both. However, double-labeled fibers and terminals were found to be distributed at a low density throughout the thalamus, the media l hypothalamus, the tegmentum and the spinal cord. These data provide the first indication for the co-localization of CCK-8 and GnRH, whose functional significance remains to be established. (C) 1998 Elsevier S cience Ireland Ltd.