Distribution of an orphan G-protein coupled receptor (JP05) mRNA in the human brain

JP05, also called GPR72 or GIR, is an orphan G-protein-coupled receptor, GPCR, showing significant structural similarity to the tachykinin receptors. The anatomical distribution of JP05 mRNA was first described in the central nervous system of the mouse, and recently the human JP05 orphan receptor gene has been cloned. In the present study the distribution of JP05 mRNA was examined in the human forebrain using in situ hybridization analysis. The results revealed a wide but discrete distribution of the transcript with strongly JP05 mRNA expressing cells, presumably neurons, present in the cerebral cortex (layer II), hippocampus (pyramidal CA3 neurons and granule cells), amygdala (basal and periamygdaloid cortical nuclei), in the endopiriform nucleus, diagonal band of Broca, thalamus (nucleus reuniens, parafascicular nucleus) and hypothalamus (posterior, dorsal, and around the medial mammillary). Weaker signals were detected in the deeper cortical layers and throughout the striatum. A few positive cells were evident in the raphe but not in the substantia nigra or pontine nuclei. The results indicate significant similarities between human and mouse brain with regard to JP05 mRNA expression. The distribution patterns of JP05 mRNA in the human brain suggest involvement in control of emotions and of neuroendocrine, cognitive and motor functions.