Colocalization Of OB-Rb MRNA And LHRH In The Forebrain And Distribution Of Orexin A In Piglets

1 Colocalization of OB-Rb mRNA and LHRH in the forebrain of pigletsIn order to find the morphological evidence that leptin plays a role in control of reproductive endocrine in the level of the hypothalamus, coexistence of OB-Rb mRNA and LHRH-like immunoreactive (LHRH-1R) in neurons of the pig forebrain was studied by combination of in situ hybridization and immunohistochemistry methods. The results! shown that both OB-Rb mRNA and LHRH-IR containing neurons(dual labelled neurons) were seen in the hypothalamus, hippocampal formation, amygdala and cerebral cortex of the pig, and that some of neurons expressing OB-Rb mRNA also containing LHRH-IR. It meant coexistence of OB-Rb mRNA and LHRH-IR in these neurons of the pig forebrain. In the hypothalamus, dual labeled neurons were seen in the paraventricular nucleus, periventricular nucleus, ventromedial nucleus, lateral area and arcuate nucleus. In the hippocampal formation, dual labeled neurons were mainly found in the polymorphic layer and the granular layer of the dentate gyrus and in the pyramidal layer of the hippocampus. In the cerebral cortex , dual labeled neurons were mainly observed in the III- V layers. The results suggested that leptin probably regulate endocrine and reproduction of animal through directly imposing on the LHRH neurons expressing OB-Rb in the hypothalamus.2 Localization of orexin A in the central nervous system and periphery organs of pigletsThe localization of orexin A in the brain and some periphery organs of pig was studied by immunohistochemistry. The results shown that orexin-like immunoreactive (orexin-IR) cells were observed in the hypothalamus, testis, adrenal gland, pancreas, small intestine, thyroid gland and thymus. In the hypothalamus, orexin-IR neurons were present in the medial preoptic nucleus, periventricular nucleus, paraventricularnucleus, supraoptic nucleus, dorsomedial nucleus, perifornical nucleus, mammillary nucleus, anterior area, lateral area and posterior area, with majority in the lateral area, supraoptic nucleus and mammillary nucleus and with minority in periventricular nucleus. In the periphery organs, orexin-IR cells were widely found in the testis, pancreas, small intestine and rarely observed in the adrenal gland, thyroid gland and thymus. Our results were similar to those obtained from the sheep. But there were some differences. These similarities and differences meant the conservative of phylogeny and species difference.