钙会改变完整水平细胞对多巴胺拮抗剂的敏感性。
Calcium alters the sensitivity of intact horizontal cells to dopamine antagonists.
作者信息
Van Buskirk R, Dowling J E
出版信息
Proc Natl Acad Sci U S A. 1982 May;79(10):3350-4. doi: 10.1073/pnas.79.10.3350.
Horizontal cells of the carp retina possess dopamine receptors linked to adenylate cyclase. Isolated, intact horizontal cells respond to micromolar concentrations of dopamine, whereas nanomolar concentrations of haloperidol, (+)-butaclamol, and flupenthixol block the dopamine response. Preincubation in Ringer's solution containing increased levels of Ca2+ (5-110 mM) decreases the sensitivity of the cells to these antagonists by 1,000-10,000 times. Dopamine sensitivity of the cells is not affected by Ca2+ levels in the preincubation medium. Preincubation of the cells in Ringer's solution containing 500 microM L-glutamate, an agent that increases intracellular Ca2+ levels in intact horizontal cells, also decreases the sensitivity of the cells to haloperidol. These data suggest that antagonist sensitivity of intact horizontal cells may be regulated by intracellular Ca2+.
鲤鱼视网膜的水平细胞拥有与腺苷酸环化酶相连的多巴胺受体。分离的完整水平细胞对微摩尔浓度的多巴胺有反应，而纳摩尔浓度的氟哌啶醇、（+）-布他拉莫和三氟噻吨会阻断多巴胺反应。在含有升高的Ca2+水平（5-110 mM）的林格氏溶液中预孵育会使细胞对这些拮抗剂的敏感性降低1000-10000倍。细胞的多巴胺敏感性不受预孵育培养基中Ca2+水平的影响。在含有500 microM L-谷氨酸的林格氏溶液中预孵育细胞，L-谷氨酸是一种能增加完整水平细胞内Ca2+水平的试剂，这也会降低细胞对氟哌啶醇的敏感性。这些数据表明，完整水平细胞的拮抗剂敏感性可能受细胞内Ca2+的调节。
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