Application of the polymerase chain reaction to the RNase protection assay for 5-HT(1B) receptor mRNA levels measurement in rat brain tissues

Expression of lipopolysaccharide-associated receptors in different human intestinal epithelial cells

AIM: To investigate the expression of lipopolysaccharide (LPS)-associated receptors-CD14, Toll-like receptor 4 (TLR4) and MD-2 in human intestinal epithelial cells (IECs) and to discuss the molecular mechanism by which IECs tolerated to LPS.

METHODS: The expression of CD14, TLR4 and MD-2 mRNA of human normal intestinal epithelial cells (HNIEC) and human intestinal epithelial cell line (HIC) was detected by RNase protection assay (RPA). The expression of CD14, TLR4 and MD-2 proteins on normal human small intestinal and colonic epithelial cells was detected by immunohis-tochemistry, and THP1 cells were used as positive control.

RESULTS: HNIEC expressed very low CD14, TLR4 and MD-2 mRNA and HICs did not express them. Neither normal human small intestinal nor colonic epithelial cells expressed TLR4, CD14 and MD2 proteins.

CONCLUSION: Low or loss of expression of TLR4, CD14 and MD-2 on IECs may be an important molecular mechanism by which IECs tolerate to lipopolysaccharide, and this will be helpful to understand the pathogenesis of inflammatory bowel disease.

The effects of long-term adrenalectomy on 5-HT1B receptors mRNA expression in cerebellum, striatum, frontal cortex and hippocampus of rats

The brain serotonin (5-HT) system and circulating corticosteroids are in close interaction and both implicated in the pathogenesis of affective disorders. We evaluated the effects of adrenalectomy (ADX) on 5-HT(1B) receptors mRNA expression in cerebellum, frontal cortex, striatum and hippocampus in rats, using the RNase protection assay technique. Eight weeks after bilateral adrenalectomy, 5-HT(1B) receptor mRNA levels were decreased in the cerebellum and in the frontal cortex. The expression of 5-HT(1B) receptors mRNA was unchanged in the hippocampus and in the striatum. This data indicates regional differences in the effects of long term adrenalectomy on the expression of 5-HT(1B) receptors.

Endurance training effects on 5-HT(1B) receptors mRNA expression in cerebellum, striatum, frontal cortex and hippocampus of rats

The 5-HT(1B) receptors are the predominant auto- and heteroreceptors located on serotonergic and non-serotonergic terminals where they regulate the neuronal release of neurotransmitters. The present study investigated the effects of a 7 week period of physical training on the expression of cerebral 5-HT(1B) receptors by measuring corresponding mRNA levels in rat. Using RNase protection assay technique, we have observed no change in 5-HT(1B) receptor mRNA levels in the striatum and in the hippocampus after moderate as well as after intensive training. In contrast, a significant decrease in 5-HT(1B) receptor mRNA levels was observed in cerebellum of intensively trained rats. Moreover, in frontal cortex, a significant decrease in 5-HT(1B) receptors mRNA level occurred in both groups of trained rats. These data suggest the existence of regional differences in the effect of physical exercise on the expression of 5-HT(1B) receptors.