This is a revised proposal for a renewal of project NS29514 on the characterization of the phosphoinositide linked dopamine (DA) receptor. Evidence obtained under this grant supports the existence of the brain DA receptor subtype which is linked to the phosphoinositide second messenger pathway. The receptor appears to be a D1/5 like DA receptor, differing from the classically defined dopamine receptor by coupling to phospholipase C via Gq protein. This potentially novel receptor may mediate some of the physiological and pharmacological effects of DA which cannot be accounted for by the adenylyl cyclase-linked DA receptors. Consequently, the understanding of the actions of DA that are mediated via this receptor has potential implications for therapeutics and diagnosis of various DA-associated neuropathologies, including schizophrenia, Parkinsonism, Huntington's chorea and tardive dyskinesia. Characterizing the functional significance of this receptor protein will depend, to a large extent, on the successful cloning of the cDNA which encodes it. The applicant s preliminary efforts to this end resulted in the identification of a cell line which exclusively expresses the principal investigator-linked DA receptor. Obtaining this cell line facilitated the cloning of this unique DNA fragment which contains elements that are highly conserved among all G-protein coupled receptors. A series of experiments are proposed with the following specific aims: (a) to continue and define the components which transduce signals initiated by this receptor in brain tissue, (b) to isolate the full length DNA which encodes this receptor by screening a DNA library constructed from a human cDNA or from the selected cell line, and determine its nucleotide sequence, and restriction map; c) determine the tissue distribution and relative abundance of the novel receptor message in rat brain, and (d) identify its ligand binding and G-protein coupling domains by expressing and analyzing the characteristics of mutant variants of the receptor. The results of this project will lay a solid foundation for the greater understanding of the role of DA in CNS function and dysfunction, and for evaluating and possibly redefining various models of DA-associated neuropathologies.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS029514-09
Application #
6126233
Study Section
Neurological Sciences Subcommittee 1 (NLS)
Program Officer
Oliver, Eugene J
Project Start
1998-11-11
Project End
2001-11-30
Budget Start
1999-12-01
Budget End
2001-11-30
Support Year
9
Fiscal Year
2000
Total Cost
$202,412
Indirect Cost
Name
Mcp Hahnemann University
Department
Pharmacology
Type
Schools of Medicine
DUNS #
City
Philadelphia
State
PA
Country
United States
Zip Code
19102
Schmidt, Azriel; Vogel, Robert; Rutledge, Su Jane et al. (2005) Cross-talk between an activator of nuclear receptors-mediated transcription and the D1 dopamine receptor signaling pathway. Pharmacol Biochem Behav 80:379-85
Jin, Li-Qing; Goswami, Satindra; Cai, Guoping et al. (2003) SKF83959 selectively regulates phosphatidylinositol-linked D1 dopamine receptors in rat brain. J Neurochem 85:378-86
Cai, Guoping; Wang, Hoau-Yan; Friedman, Eitan (2002) Increased dopamine receptor signaling and dopamine receptor-G protein coupling in denervated striatum. J Pharmacol Exp Ther 302:1105-12
Zhen, X; Zhang, J; Johnson, G P et al. (2001) D(4) dopamine receptor differentially regulates Akt/nuclear factor-kappa b and extracellular signal-regulated kinase pathways in D(4)MN9D cells. Mol Pharmacol 60:857-64
Jin, L Q; Wang, H Y; Friedman, E (2001) Stimulated D(1) dopamine receptors couple to multiple Galpha proteins in different brain regions. J Neurochem 78:981-90
Cai, G; Zhen, X; Uryu, K et al. (2000) Activation of extracellular signal-regulated protein kinases is associated with a sensitized locomotor response to D(2) dopamine receptor stimulation in unilateral 6-hydroxydopamine-lesioned rats. J Neurosci 20:1849-57
Can, A; Sayar, K; Friedman, E et al. (2000) The effects of agonist stimulation and beta(2)-adrenergic receptor level on cellular distribution of gs(alpha) protein. Cell Signal 12:303-9
Cai, G; Gurdal, H; Smith, C et al. (1999) Inverse agonist properties of dopaminergic antagonists at the D(1A) dopamine receptor: uncoupling of the D(1A) dopamine receptor from G(s) protein. Mol Pharmacol 56:989-96
Jin, L Q; Cai, G; Wang, H Y et al. (1998) Characterization of the phosphoinositide-linked dopamine receptor in a mouse hippocampal-neuroblastoma hybrid cell line. J Neurochem 71:1935-43
Zhen, X; Uryu, K; Wang, H Y et al. (1998) D1 dopamine receptor agonists mediate activation of p38 mitogen-activated protein kinase and c-Jun amino-terminal kinase by a protein kinase A-dependent mechanism in SK-N-MC human neuroblastoma cells. Mol Pharmacol 54:453-8

Showing the most recent 10 out of 22 publications