Crook R B, Polansky J R
Department of Ophthalmology, University of California, San Francisco.
Invest Ophthalmol Vis Sci. 1992 Apr;33(5):1706-16.
The effects of several neurotransmitters and neuropeptides on the inositol phosphate/diacylglycerol pathway were examined in human nonpigmented ciliary epithelial cells. Maximal stimulation of inositol phosphate formation by vasopressin (approximately 3-fold), carbachol (approximately 2-fold) and histamine (approximately 5-fold) was observed only after cells had been confluent for at least six days. In contrast, a response to bombesin (approximately 3-fold) declined with extended time in confluent culture. Inositol monophosphate, inositol bisphosphate, and inositol trisphosphate all were stimulated by these agonists. Dose-response studies showed a close correlation between the EC50s of the different agonists when elevation of inositol phosphates was compared to stimulation of intracellular Ca2+, with the exception of bombesin. Preliminary pharmacologic characterization of the receptors for vasopressin, carbachol, and bombesin provided rank order of potencies for selective agonists and antagonists. The data suggest that the muscarinic receptor on human NPE cells is the M3 subtype, whereas the vasopressin receptor, as defined by its linkage to the inositol phosphate/diacylglycerol pathway, is the V1 subtype.
在人无色素睫状上皮细胞中研究了几种神经递质和神经肽对肌醇磷酸/二酰基甘油途径的影响。仅在细胞汇合至少六天后，才观察到血管加压素（约3倍）、卡巴胆碱（约2倍）和组胺（约5倍）对肌醇磷酸形成的最大刺激作用。相比之下，在汇合培养中，随着时间延长，对蛙皮素（约3倍）的反应下降。这些激动剂均可刺激单磷酸肌醇、二磷酸肌醇和三磷酸肌醇。剂量反应研究表明，除蛙皮素外，当将肌醇磷酸的升高与细胞内Ca2+的刺激进行比较时，不同激动剂的半数有效浓度（EC50）之间存在密切相关性。对血管加压素、卡巴胆碱和蛙皮素受体的初步药理学特征分析提供了选择性激动剂和拮抗剂的效价排序。数据表明，人无色素睫状上皮细胞上的毒蕈碱受体是M3亚型，而通过其与肌醇磷酸/二酰基甘油途径的联系所定义的血管加压素受体是V1亚型。
