DISTRIBUTION OF OREXIN RECEPTOR MESSENGER-RNA IN THE RAT-BRAIN

The expression pattern of mRNA encoding two orexin receptors (OX1R and OX2R) in the rat brain was examined. OX1R and OX2R exhibited marked d ifferential distribution. Within the hypothalamus, OX1R mRNA is most a bundant in the ventromedial hypothalamic nucleus whereas OX2R is predo minantly expressed in the paraventricular nucleus, High levels of OX1R mRNA were also detected in tenia tecta, the hippocampal formation, do rsal raphe, and locus coeruleus, OX2R mRNA is mainly expressed in cere bral cortex, nucleus accumbens, subthalamic and paraventricular thalam ic nuclei, anterior pretectal nucleus. The presence of orexin receptor mRNA in the hypothalamus is in support of its proposed role in feedin g regulation, Broad central distribution of orexin receptors may indic ate additional functions for orexins, (C) 1998 Federation of European Biochemical Societies.