title: Modulation of Ca2+ signals by phosphatidylinositol-linked novel D1 dopamine receptor in hippocampal neurons.
abstract: Recent evidence indicates the existence of a putative novel phosphatidylinositol-linked D1 dopamine receptor in brain that mediates phosphatidylinositol hydrolysis via activation of phospholipase Cbeta. The present work was designed to characterize the Ca(2+) signals regulated by this phosphatidylinositol-linked D(1) dopamine receptor in primary cultures of hippocampal neurons. The results indicated that stimulation of phosphatidylinositol-linked D1 dopamine receptor by its newly identified selective agonist SKF83959 induced a long-lasting increase in basal [Ca(2+)](i) in a time- and dose-dependent manner. Stimulation was observable at 0.1 microm and reached the maximal effect at 30 microm. The [Ca(2+)](i) increase induced by 1 microm SKF83959 reached a plateau in 5 +/- 2.13 min, an average 96 +/- 5.6% increase over control. The sustained elevation of [Ca(2+)](i) was due to both intracellular calcium release and calcium influx. The initial component of Ca(2+) increase through release from intracellular stores was necessary for triggering the late component of Ca(2+) rise through influx. We further demonstrated that activation of phospholipase Cbeta/inositol triphosphate was responsible for SKF83959-induced Ca(2+) release from intracellular stores. Moreover, inhibition of voltage-operated calcium channel or NMDA receptor-gated calcium channel strongly attenuated SKF83959-induced Ca(2+) influx, indicating that both voltage-operated calcium channel and NMDA receptor contribute to phosphatidylinositol-linked D(1) receptor regulation of [Ca(2+)](i).
authors.affiliation: Department of Pharmacology, Tongji Medical College, Huazhong University of Science and Technology, HUST, Wuhan, China.
authors.forename: Yuling
authors.initials: Y
authors.lastname: Ming
authors.forename: Hai
authors.initials: H
authors.lastname: Zhang
authors.forename: Lihong
authors.initials: L
authors.lastname: Long
authors.forename: Fang
authors.initials: F
authors.lastname: Wang
authors.forename: Jianguo
authors.initials: J
authors.lastname: Chen
authors.forename: Xuechu
authors.initials: X
authors.lastname: Zhen
mesh_terms: D015647:2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D000831:Animals, Newborn / Q000502:physiology; D002118:Calcium / Q000378:metabolism; D020746:Calcium Channels, L-Type / Q000187:drug effects; D020013:Calcium Signaling / Q000502:physiology*; D002478:Cells, Cultured; D018491:Dopamine Agonists / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006624:Hippocampus / Q000166:cytology / Q000502:physiology*; D007527:Isoenzymes / Q000378:metabolism; D009474:Neurons / Q000502:physiology*; D010716:Phosphatidylinositols / Q000502:physiology*; D054799:Phospholipase C beta; D051381:Rats; D017207:Rats, Sprague-Dawley; D017447:Receptors, Dopamine D1 / Q000502:physiology*; D015290:Second Messenger Systems / Q000502:physiology; D019284:Thapsigargin / Q000494:pharmacology; D010738:Type C Phospholipases / Q000378:metabolism
chemical_list: D020746:Calcium Channels, L-Type; D018491:Dopamine Agonists; D004791:Enzyme Inhibitors; D007527:Isoenzymes; D010716:Phosphatidylinositols; D017447:Receptors, Dopamine D1; D015647:2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine; D019284:Thapsigargin; C080703:SK&F 83959; D010738:Type C Phospholipases; D054799:Phospholipase C beta; D002118:Calcium