Mapping of motilin-immunoreactive neurons of the rat brain.

Motilin immunofluorescence was observed in the rat brain by means of N- and C-terminally directed antisera. A detailed mapping of the localization of motilin-like immunoreactive neurons in the rat forebrain is presented. Colchicine pretreatment revealed many cell bodies in the mediobasal hypothalamus. A small number of cells were observed in the organum vasculosum lamina terminalis (OVLT) region. A rich innervation of varicose fibers was observed in the median eminence and OVLT. Fibers of varying densities were observed in the preoptic area, nucleus interstitialis stria terminalis, hypothalamic nuclei, basal hypothalamus, amygdala, mammillary doby and central gray. The localization of these neurons suggests that motilin, like other brain peptides serves a variety of functions including neuroendocrine regulation.