Gupta S K, Mishra R K
Department of Psychiatry, Faculty of Health Sciences, McMaster University, Hamilton, Ontario, Canada.
Biochem Int. 1990 Dec;22(5):887-94.
There is a lot of controversy in the literature about the role of dopamine D1 and D2 receptor stimulation on the turnover of phosphoinositols, and phosphoinositols are one of the important second messenger. In order to resolve this controversy, the effect of dopamine receptor stimulation on turnover of phosphoinositols was studied by estimation of the accumulation of individual labelled inositols in rat striatal slices which were prelabelled with [3H]myoinositol. Incubation of the prelabelled striatal slices with 1 microM of quinpirole, D2 specific agonist or with 1 microM of SKF-38393, D1 specific agonist, did not affect the accumulation of basal level of either inositol monophosphate, or inositol biphosphate, or inositol triphosphate. In addition, in conclusion of D1 specific antagonist cis-flupentixol or D2 specific antagonist sulpiride did not affect the basal levels of inositol phosphates. The activity of enzyme phospholipase-C which produces these inositol phosphates was also measured in rat striatal membrane. Incubation of rat striatal membrane with either agonist quinpirole or SKF-38393 did not change the basal level of phospholipase C. Our data thus indicate that occupation of dopamine receptors did not affect the inositol phosphate system in rat striatum.
关于多巴胺D1和D2受体刺激对磷酸肌醇周转的作用，文献中有很多争议，而磷酸肌醇是重要的第二信使之一。为了解决这一争议，通过估算预先用[3H]肌醇标记的大鼠纹状体切片中单个标记肌醇的积累，研究了多巴胺受体刺激对磷酸肌醇周转的影响。用1微摩尔喹吡罗（D2特异性激动剂）或1微摩尔SKF - 38393（D1特异性激动剂）孵育预先标记的纹状体切片，对肌醇一磷酸、肌醇二磷酸或肌醇三磷酸的基础水平积累均无影响。此外，D1特异性拮抗剂顺式氟哌噻吨或D2特异性拮抗剂舒必利也不影响肌醇磷酸的基础水平。还在大鼠纹状体膜中测量了产生这些肌醇磷酸的磷脂酶C的活性。用激动剂喹吡罗或SKF - 38393孵育大鼠纹状体膜，并未改变磷脂酶C的基础水平。因此，我们的数据表明，占据多巴胺受体不会影响大鼠纹状体中的肌醇磷酸系统。
