title: Ceramide inhibits L-type calcium channel currents in GH3 cells.
abstract: In this study, we investigated the effect of ceramide on the L-type Ca2+ channel (L-channel) in GH3 cells. We found that C6-ceramide, but not C6-dihydroceramide, the inactive analogue, had an inhibitory effect on BayK 8644-stimulated GH release. Using patch clamp analysis, C6- and C2-ceramide, but not C6-dihydroceramide, were found to inhibit the L-channel current. Increasing intracellular ceramide level with sphingomyelinase also inhibited the L-channel current. The inhibitory effect of ceramide on the L-channel current was attenuated by calphostin C, a myristolated pseudosubstrate protein kinase C (PKC) inhibitor, and lavendustin A, a tyrosine kinase inhibitor. Combined treatment with lavendustin A and the myristolated PKC inhibitor blocked the effect of ceramide on the L-channel current. These results indicate that ceramide, a lipid messenger of the sphingomyelin pathway, is an important regulator of the L-channel in GH3 cells and both tyrosine kinase and PKC are involved in this effect of ceramide.
authors.affiliation: Department of Medicine, 7-33 Medical Sciences Building, Edmonton, Alta., Canada T6G 2H7. cchik@ualberta.ca
authors.forename: C L
authors.initials: CL
authors.lastname: Chik
authors.forename: B
authors.initials: B
authors.lastname: Li
authors.forename: E
authors.initials: E
authors.lastname: Karpinski
authors.forename: A K
authors.initials: AK
authors.lastname: Ho
mesh_terms: D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester / Q000378:metabolism; D000818:Animals; D002118:Calcium / Q000378:metabolism; D002120:Calcium Channel Agonists / Q000378:metabolism; D002121:Calcium Channel Blockers / Q000378:metabolism*; D020746:Calcium Channels, L-Type / Q000378:metabolism*; D002460:Cell Line; D002518:Ceramides / Q000737:chemistry / Q000378:metabolism*; D004594:Electrophysiology; D004791:Enzyme Inhibitors / Q000378:metabolism; D009281:Naphthalenes / Q000378:metabolism; D010636:Phenols / Q000378:metabolism; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism; D051381:Rats; D015290:Second Messenger Systems / Q000502:physiology; D013108:Sphingomyelin Phosphodiesterase / Q000378:metabolism; D013755:Tetradecanoylphorbol Acetate / Q000378:metabolism
chemical_list: D002120:Calcium Channel Agonists; D002121:Calcium Channel Blockers; D020746:Calcium Channels, L-Type; D002518:Ceramides; D004791:Enzyme Inhibitors; D009281:Naphthalenes; D010636:Phenols; C062898:lavendustin A; D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester; D011493:Protein Kinase C; D013108:Sphingomyelin Phosphodiesterase; C058819:calphostin C; D013755:Tetradecanoylphorbol Acetate; D002118:Calcium