Functional coupling of the NK1 tachykinin receptor to phospholipase D in chinese hamster ovary cells and astrocytoma cells.
In [3H]myristic acid-prelabeled Chinese hamster ovary cells stably expressing the rat NK1 tachykinin receptor, the selective NK1 agonist [Pro9]substance P ([Pro9]SP) time and concentration dependently stimulated the formation of [3H]phosphatidylethanol in the presence of ethanol. This [Pro9]SP-induced activation of phospholipase D (PLD) was blocked by NK1 receptor antagonists and poorly or not mimicked by NK2 and NK3 agonists, respectively. In confirmation of previous observations, [Pro9]SP also stimulated the hydrolysis of phosphoinositides, the release of arachidonic acid, and the formation of cyclic AMP (cAMP). All these [Pro9]SP-evoked responses could be mimicked by aluminum fluoride, but they remained unaffected in cells pretreated with pertussis toxin, suggesting that a Gi/Go protein is not involved in these different signaling pathways. The activation of PLD by [Pro9]SP was sensitive to external calcium and required an active protein kinase C because the inhibition of this kinase (Ro 31-8220) or its down-regulation (long-term treatment with a phorbol ester) abolished the response. In contrast, a cAMP-dependent process was not involved in the activation of PLD because the [Pro9]SP-evoked response was neither affected by Rp-8-bromoadenosine 3',5'-cyclic monophosphorothioate nor mimicked by cAMP-generating compounds (cholera toxin or forskolin) or by 8-bromo-cyclic AMP. A functional coupling of NK1 receptors to PLD was also demonstrated in the human astrocytoma cell line U 373 MG stimulated by SP or [Pro9]SP. These results suggest that PLD activation could be an additional signaling pathway involved in the mechanism of action of SP in target cells expressing NK1 receptors.
Torrens
Y
Y
Neuropharmacologie, INSERM U114, Collège de France, Paris.
Beaujouan
J C
JC
Saffroy
M
M
Glowinski
J
J
Tencé
M
M
D000818:Animals; D001254:Astrocytoma / Q000378:metabolism* / Q000473:pathology; D016466:CHO Cells / Q000378:metabolism*; D002118:Calcium / Q000494:pharmacology; D006224:Cricetinae; D000242:Cyclic AMP / Q000502:physiology; D004789:Enzyme Activation / Q000187:drug effects; D019204:GTP-Binding Proteins / Q000502:physiology; D020404:Glycerophospholipids; D006801:Humans; D019814:Myristic Acid / Q000378:metabolism; D010712:Phosphatidic Acids / Q000096:biosynthesis; D010713:Phosphatidylcholines / Q000378:metabolism; D010739:Phospholipase D / Q000378:metabolism*; D011493:Protein Kinase C / Q000502:physiology; D051381:Rats; D018040:Receptors, Neurokinin-1 / Q000378:metabolism*; D013373:Substance P / Q000031:analogs & derivatives / Q000494:pharmacology; D015320:Tachykinins / Q000494:pharmacology; D014407:Tumor Cells, Cultured
D020404:Glycerophospholipids; D010712:Phosphatidic Acids; D010713:Phosphatidylcholines; D018040:Receptors, Neurokinin-1; D015320:Tachykinins; C051521:phosphatidylethanol; D019814:Myristic Acid; C067285:substance P, Pro(9)-; D013373:Substance P; D000242:Cyclic AMP; D011493:Protein Kinase C; D010739:Phospholipase D; D019204:GTP-Binding Proteins; D002118:Calcium