Distribution of parathyroid hormone-2 receptor-like immunoreactivity and messenger RNA in the rat nervous system

The parathyroid hormone-2 receptor is a member of the secretin family of gu anine nucleotide-binding protein-coupled receptors, The human parathyroid h ormone-2, receptor is activated by parathyroid hormone and a recently purif ied hypothalamic polypeptide, tubero-infundibular peptide of 39 residues, w hile the rat parathyroid hormone-2 receptor is poorly activated by parathyr oid hormone and is potently activated by tubero-infundibular peptide of 39 residues. In order to provide a foundation for studies on the physiological role of the parathyroid hormone-2 receptor and tubero-infundibular peptide of 39 residues, we investigated the cellular distribution of the parathyro id hormone-2 receptor in the rat CNS using both immunohistochemistry and in situ hybridization histochemistry. The receptor is found in discrete group s of neurons in many regions. It is present in scattered small cells throug hout the cerebral cortex, in small and medium-sized cells in the striatum, and is quite abundant in the septum and the midline thalamic nuclei. Its ex pression is high in the hypothalamus, particularly in the periventricular a nd arcuate nuclei. Fibers and terminals in the external zone of the median eminence, and in the superficial layers of the caudal spinal trigeminal tra ct and the spinal cord dorsal horn, art: strongly and dramatically labeled by a parathyroid hormone-2 receptor-selective antibody. The localization of parathyroid hormone-2 receptor suggests a role in the regulation of pituit ary hormone secretion, sensory information processing and homeostatic regul ation. Published by Elsevier Science Ltd.