Restraint stress enhances the gene expression of prolactin receptor long form at the choroid plexus.

Abstract

Hormonal control of brain functions is considered to be important in the tolerance of stress, and it is now established that stress elevates serum PRL levels in male or cycling female rats. To investigate whether or how serum PRL acts on the brain during exposure to stress, we analyzed serum PRL levels and the gene expression of brain PRL receptors in rats subjected to restraint stress in the water (RSW). The serum PRL concentration was remarkably increased within 30 min in the rats by exposure to RSW and decreased to the initial level after 4 h of RSW, remaining at this level for up to 7 h of RSW. After the rats were released from the stress, the serum PRL level was significantly lowered in 6 h. Ribonuclease protection assay and in situ hybridization analysis revealed that messenger RNA (mRNA) expression for the long form PRL receptor [PRL-R(L)] was remarkably induced in the rat choroid plexus in 2 h of RSW. The high expression level of PRL-R(L) mRNA in the region was reduced after the rats were released from the stress. PRL-R(L) mRNA expression in the hypothalamus was at lower levels than those in the choroid plexus before and during the RSW treatment. The short form PRL receptor mRNA expression in the rat brain was considerably lower than expression of the long form receptor mRNA before or during RSW. The results indicated that the restraint stress caused a rapid increase in serum PRL and induced the gene expression for PRL-R(L) in the choroid plexus, suggesting stress-induced and choroid plexus PRL-R(L)-mediated transport of serum PRL into the cerebrospinal fluid.

Regulation of Prolactin Receptor Gene Expression in the Rat Choroid Plexus via Transcriptional Activation of Multiple First Exons during Postnatal Development and Lactation

“…the long-form PrLr is known to be involved in most of the PrL functions mediated by the Jak2/stat5 (janus kinase 2/signal transducer and activator of transduction 5) intracellular signaling pathway [5,10,14], whereas the function and intracellular signaling system of the short-form PrLr is poorly understood. in the rat choroid plexus, the expression of the long-and short-form PRLR mrNas has been observed [3,4,15,27,30]. the molecular mechanisms of transcriptional activation of the E1 4 first exon, and the transport system of PrL mediated by long-or short-form PrLr in the choroid plexus remain to be elucidated.…”

Endocrinological Differences between Hatano High- and Low-Avoidance Rats during Early Two-Way Avoidance Acquisition

“…Stress induces the expression of the long-form of the prolactin receptors in choroid plexus and PVN cells [4,17,19]. Administration of prolactin into the cerebral ventricles prevents stress-induced formation of gastric ulcers and shows antidepressant effects during forced swimming [14][15][16].…”

Subcutaneously Administered Prolactin and 20K hGH, but not rGH or 22K hGH, Prevent Restraint Stress-Induced Gastric Ulcers in Rats

“…After 6 days, the animals with the osmotic minipumps were subjected to RSW by putting into individual restraining wire net cages, and immersing in water (23 ±0.5°C) to the chest. After 7 h of RSW, the animals were taken out from the restraining cages and decapitated as described previously [13]. Blood from each rat was used for the measurement of serum rPRL and rGH.…”