Improved visualization of luteinizing hormone releasing hormone pathways by immunocytochemical staining of thick vibratome sections.

Using 100-micron thick Vibratome sections and a modification of the peroxidase--antiperoxidase method of immunocytochemical staining we achieve a Golgi-like image of luteinizing hormone releasing hormone (LHRH) cells and fibers in mouse brain. Five LHRH pathways are described: 1) A dense projection of fibers from LHRH cells in the medial preoptic and septal areas to the wall of the third ventricle; 2) a projection of fibers from neurons in the bed nucleus of the stria terminalis and the nucleus of the anterior commissure to the subfornical organ; 3) projections of fibers from neurons in the medial septal nucleus and the diagonal band of Broca to the olfactory bulb; 4) fibers which travel within or just lateral to the wall of the third ventricle from the organum vasculosum laminae terminalis to the median eminence; 5) cells and fibers located just dorsal to the optic tracts which project rostrally to the preoptic area and caudally to the level of the median eminence where they course medially to converge and enter the median eminence.