Objective To exam the expression and the distribution difference between melatonin membrane receptor subtype Mel 1a and Mel 1b in the central nervous system of rats. Methods In situ hybridization technique was used. Results (1)The Mel 1a mRNA positive cells were mainly detected in the hippocampus,cerebral cortex,supraoptic nucleus,paraventricular nucleus,suprachiasmatic nucleus,inferior olivary nucleus,cortex and fastigial nucleus of cerebellar,ventral horn of the spinal cord,facial nerve nucleus,gigantocellular reticular nucleus,striatum cortex and trigeminal nerve nucleus,etc.(2)The Mel 1b mRNA positive cells were mainly observed in the cerebellar cortex,fastigial nucleus,global nucleus,emboliform nucleus of the medullaris cerebelli,hippocampus,cerebral cortex,ventral horn of the spinal cord,supraoptic nucleus and suprachiasmatic nucleus.Conclusion\ Mel 1a mRNA positive neurons were abundant and distributed widely in the CNS,while Mel 1b mRNA\|positive neurons distributed comparatively localized.However,the hippocampus and the cortex were two regions which were rich in both Mel 1a and Mel 1b mRNA positive neurons.\;[

AIM: To observe the effect of adrenocorticotropic hormone(ACTH) on the levels of brain-derived neurotrophic factor (BDNF), trkB and corticotropin-releasing hormone(CRH) in the hippocampus of arthritic rats.METHODS: The BDNF immunoreactivity (IR) and CRH-positive neurons were stained with immunohistochemistry and in situ hybridization methods, respectively.RESULTS: The BDNF-IR, CRH mRNA-positive neurons in the contralateral hippocampus of the arthritic rats were increased significantly, which was decreased markedly by intraperitoneal injection of ACTH. However, the effect of ACTH was attenuated after adrenalectomy (ADX).CONCLUSION: These results suggest that BDNF and CRH in the hippocampus of arthritic rats were involved in the modulation of chronic pain, ACTH produced its analgesic effect by inhibiting the increase in BDNF and CRF level. Adrenal is critical to the analgesic action of ACTH.