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.