Identification of functional dopamine receptors in human teratocarcinoma NT2 cells.
In search of a cellular model suitable for studying molecular events contributing to brain disorders, we have characterised the expression and functionality of dopamine receptors in human teratocarcinoma NT2 cells. The cells were differentiated by a 4-week retinoic acid treatment, followed by a 3-week mitotic inhibitor treatment in the absence of retinoic acid. The messages of two D(2)-like family members, D(2L) and D(3), were expressed in undifferentiated NT2 cells. The retinoic acid treatment resulted in increased expression of both spliced variants of the D(2) receptor, D(2L) and D(2S) isoforms and a significant induction of D(1) and D(5) gene transcripts. The same treatment turned off expression of the D(3) gene. Further induction of the D(5) gene was observed in the post-mitotic NT2N neurons. The NT2N cells stained positively for D(2) and D(5) receptor proteins, and the intracellular cyclic AMP level increased in response to forskolin, dopamine and the D(1)-receptor agonist SKF-81297. Furthermore, dopamine was ineffective in the presence of the D(2) receptor agonist PPHT and the D(1) receptor antagonist cis-(z)-flupenthixol. These results indicated that upon ligand/agonist/antagonist binding, the receptors could be coupled to the adenylyl cyclase system, hence were functional. To our knowledge, NT2 is the only human immortalized cell line expressing functional dopamine receptors of both families.
Sodja
Caroline
C
Apoptosis Research Group, Institute for Biological Sciences, National Research Council of Canada, 1500 Montreal Road, Bldg. M-54, Ottawa, ON, K1A 0R6, Canada.
Fang
Hung
H
Dasgupta
Tina
T
Ribecco
Maria
M
Walker
P Roy
PR
Sikorska
Marianna
M
D000262:Adenylyl Cyclases / Q000187:drug effects / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology*; D002461:Cell Line, Transformed / Q000187:drug effects / Q000378:metabolism*; D000242:Cyclic AMP / Q000378:metabolism; D018491:Dopamine Agonists / Q000494:pharmacology; D018492:Dopamine Antagonists / Q000494:pharmacology; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D008024:Ligands; D008959:Models, Neurological; D011485:Protein Binding / Q000187:drug effects / Q000502:physiology; D012333:RNA, Messenger / Q000378:metabolism; D011954:Receptors, Dopamine / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism*; D018243:Teratocarcinoma / Q000378:metabolism*; D014212:Tretinoin / Q000494:pharmacology
D018491:Dopamine Agonists; D018492:Dopamine Antagonists; D008024:Ligands; D012333:RNA, Messenger; D011954:Receptors, Dopamine; D014212:Tretinoin; D000242:Cyclic AMP; D000262:Adenylyl Cyclases