Different mechanisms of Ca2+ entry induced by depolarization and muscarinic receptor stimulation in SH-SY5Y human neuroblastoma cells.
Depolarization by elevated K+ and stimulation of muscarinic M3 receptors evoke rises in [Ca2+]i in Fura 2-loaded SH-SY5Y human neuroblastoma cells. The response to K+ (30 and 60 mM) could be inhibited by the dihydropyridine L-channel antagonist +PN 200-110 and totally suppressed by Ni2+, the N-channel blocker omega-conotoxin reduced the response to 60 mM K+. Carbachol-stimulated increase in [Ca2+]i was blocked by atropine and Ni2+ but was totally resistant to the L- and N-channel blockers. This study reveals the presence of L- and N-type voltage-sensitive Ca2+ channels on undifferentiated SH-SY5Y cells that are opened by K+ depolarization but not by muscarinic stimulation.
Lambert
D G
DG
Department of Pharmacology and Therapeutics, University of Leicester, U.K.
Whitham
E M
EM
Baird
J G
JG
Nahorski
S R
SR
D001285:Atropine / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000494:pharmacology; D002217:Carbachol / Q000494:pharmacology; D002460:Cell Line; D002462:Cell Membrane / Q000187:drug effects / Q000502:physiology; D006801:Humans; D017275:Isradipine; D007700:Kinetics; D008564:Membrane Potentials / Q000187:drug effects; D009447:Neuroblastoma; D009532:Nickel / Q000494:pharmacology; D010069:Oxadiazoles / Q000494:pharmacology; D011188:Potassium / Q000494:pharmacology; D011976:Receptors, Muscarinic / Q000187:drug effects / Q000502:physiology*
D002121:Calcium Channel Blockers; D010069:Oxadiazoles; D011976:Receptors, Muscarinic; D001285:Atropine; D009532:Nickel; D002217:Carbachol; D011188:Potassium; D002118:Calcium; D017275:Isradipine