Brainstem prolactin-releasing peptide neurons are sensitive to stress and lactation


Por: Morales T., Sawchenko P.E.

Publicada: 1 ene 2003
Resumen:
Prolactin-releasing peptide (PrRP) was originally thought to participate in the control of adenohypophyseal prolactin secretion, but its predominant expression in a subset of medullary noradrenergic neurons is more in line with roles in interoceptive and/or somatosensory information processing. To better define functional contexts for this peptide system, immuno- and hybridization histochemical methods were used to monitor the capacity of PrRP neurons to display activational responses to lactation, suckling, acute footshock or hypotensive hemorrhage. PrRP mRNA signal was reduced in the medulla of lactating dams, relative to both male and diestrus female controls, with cell counts revealing 42% and 43% reductions in the number of positively hybridized cells in the nucleus of the solitary tract (NTS) and ventrolateral medulla, respectively. Lactating mothers killed after a 90 min suckling episode (following 4 h pup removal) failed to show induced Fos expression in identified medullary PrRP neurons, despite the fact that responsive neurons were detected in other aspects of the caudal NTS. By contrast, acute exposure to hypotensive (25%) hemorrhage or footshock each activated substantial complements of medullary neurons expressing PrRP mRNA. A substantially greater fraction of the total medullary PrRP population exhibited sensitivity to footshock than hemorrhage (71 versus 39%, respectively). These results suggest that medullary PrRP neurons are negatively regulated by (presumably hormonal) changes in lactation, and are not recruited to activation by suckling stimuli. These populations exhibit differential sensitivity to distinct acute stressors, and may participate in the modulation of adaptive neuroendocrine and autonomic responses to each. © 2003 IBRO. Published by Elsevier Ltd. All rights reserved.

Filiaciones:
Morales T.:
 Instituto de Neurobiologia, UNAM, Juriquilla, Qro. 76230, Mexico

Sawchenko P.E.:
 Lab. of Neuronal Struct. and Funct., Salk Inst. for Biological Studies, Foundation for Medical Research, 10010 North Torrey Pines Road, San Diego, CA 92037, United States
ISSN: 03064522
Editorial
PERGAMON-ELSEVIER SCIENCE LTD, THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND, Reino Unido
Tipo de documento: Article
Volumen: 121 Número: 3
Páginas: 771-778
WOS Id: 000186584200022
ID de PubMed: 14568035