title: Expression of RESP18 in peptidergic and catecholaminergic neurons.
abstract: We examined the expression of regulated endocrine-specific protein of 18-kD (RESP18) in selected peptidergic and catecholaminergic neurons of adult rat brain. In the hypothalamic paraventricular, supraoptic, and accessory nuclei, RESP18 mRNA was highly expressed in neurons immunostained for oxytocin and vasopressin. RESP18 mRNA was also highly expressed in paraventricular nucleus neurons immunostained for corticotropin-releasing hormone, thyrotropin-releasing hormone, and somatostatin. RESP18 mRNA was expressed in POMC cells of the arcuate nucleus, in neuropeptide Y cells of the dorsal tegmental nucleus, lateral reticular nucleus, and hippocampus, and in brainstem catecholaminergic neurons. RESP18 mRNA expression was high in all paraventricular and arcuate neurons, but RESP18 protein was detectable in the perikarya of a subset of these neurons, suggesting an important post-transcriptional component to the regulation of RESP18 expression. RESP18 antisera immunostained perikarya but not axon fibers or terminals. Sub-cellular fractionation of homogenates of several hypothalamic nuclei identified RESP18 protein in fractions enriched in endoplasmic reticulum. The presence of 22- and 24-kD RESP18 isoforms in the neural lobe of the pituitary indicated that some RESP18 protein exited the endoplasmic reticulum. The post-transcriptional regulation of RESP18 expression and localization of RESP18 protein primarily to the endoplasmic reticulum suggests that RESP18 plays a regulatory role in peptidergic neurons.
authors.affiliation: Department of Surgery, University of Maryland School of Medicine, Baltimore, USA.
authors.forename: D N
authors.initials: DN
authors.lastname: Darlington
authors.forename: M R
authors.initials: MR
authors.lastname: Schiller
authors.forename: R E
authors.initials: RE
authors.lastname: Mains
authors.forename: B A
authors.initials: BA
authors.lastname: Eipper
mesh_terms: D000320:Adrenergic Fibers / Q000378:metabolism* / Q000648:ultrastructure; D000818:Animals; D001111:Arcuate Nucleus of Hypothalamus / Q000378:metabolism; D015153:Blotting, Western; D001921:Brain / Q000378:metabolism*; D002395:Catecholamines / Q000378:metabolism; D003346:Corticotropin-Releasing Hormone / Q000378:metabolism; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D008297:Male; D009419:Nerve Tissue Proteins / Q000235:genetics*; D009474:Neurons / Q000378:metabolism* / Q000648:ultrastructure; D009478:Neuropeptide Y / Q000378:metabolism; D010121:Oxytocin / Q000378:metabolism; D010286:Paraventricular Hypothalamic Nucleus / Q000378:metabolism; D011333:Pro-Opiomelanocortin / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013004:Somatostatin / Q000378:metabolism; D013495:Supraoptic Nucleus / Q000378:metabolism; D013973:Thyrotropin-Releasing Hormone / Q000378:metabolism; D014667:Vasopressins / Q000378:metabolism
chemical_list: D002395:Catecholamines; D009419:Nerve Tissue Proteins; D009478:Neuropeptide Y; D012333:RNA, Messenger; C086381:regulated endocrine secretory protein 18; D014667:Vasopressins; D010121:Oxytocin; D013004:Somatostatin; D013973:Thyrotropin-Releasing Hormone; D011333:Pro-Opiomelanocortin; D003346:Corticotropin-Releasing Hormone