Distribution of CB1 cannabinoid receptors and their relationship with mu-opioid receptors in the rat periaqueductal gray
- 作者：A.R. Wilson-Poea ; adie.wilson@gmail.com ; M.M. Morgana ; b ; &dagger ; ; mmmorgan@vancouver.wsu.edu ; S.A. Aicherc ; &Dagger ; ; aichers@ohsu.edu ; D.M. Hegartyc ; hegartyd@ohsu.edu
- 关键词：BSA ; bovine serum albumin ; cAMP ; cyclic AMP ; CB1 ; cannabinoid 1 ; DMSO ; dimethyl sulfoxide ; EMS ; Electron Microscopy Sciences ; ERK ; extracellular-related kinase ; -ir ; immunoreactive ; MAPK ; mitogen-activated protein kinase ; MOP ; mu-opioid peptide ; NIDA ; Nat
- 刊名：Neuroscience
- 出版年：2012
- 期刊代码：50_03064522
- 类别：neu
- 出版时间：28 June, 2012
- 卷：213
- 期：Complete
- 页码：191-200
- 文件大小：1329 K
摘要
The periaqueductal gray (PAG) is part of a descending pain modulatory system that, when activated, produces widespread and profound antinociception. Microinjection of either opioids or cannabinoids into the PAG elicits antinociception. Moreover, microinjection of the cannabinoid 1 (CB1) receptor agonist HU-210 into the PAG enhances the antinociceptive effect of subsequent morphine injections, indicating a direct relationship between these two systems. The objective of this study was to characterize the distribution of CB1 receptors in the dorsolateral and ventrolateral PAG in relationship to mu-opioid peptide (MOP) receptors. Immunocytochemical analysis revealed extensive and diffuse CB1 receptor labeling in the PAG, 60%of which was found in somatodendritic profiles. CB1 and MOP receptor immunolabeling were co-localized in 32%of fluorescent Nissl-stained cells that were analyzed. Eight percent (8%) of PAG neurons that were MOP receptor-immunoreactive (-ir) received CB1 receptor-ir appositions. Ultrastructural analysis confirmed the presence of CB1 receptor-ir somata, dendrites and axon terminals in the PAG. These results indicate that behavioral interactions between cannabinoids and opioids may be the result of cellular adaptations within PAG neurons co-expressing CB1 and MOP receptors.