Role of intracellular Ca(2+)-stores in the 5-hydroxytryptamine-induced Ca(2+)-current inhibition in NG108-15 hybrid cells.
Mouse neuroblastoma x rat glioma hybrid cells (N x G, NG108-15) were used to study the mechanism of Ca(2+)-current (ICa) inhibition by 5-hydroxytryptamine (5-HT). 5-HT caused a dose-dependent decrease of ICa which was abolished by ICS 205-930 (10)(-8) M) while 2-methyl-5-HT was an agonist. Intracellular infusion of GDP beta S (50 microM) prevented the 5-HT-induced inhibition of ICa whereas pertussis toxin (PTX) pretreatment did not alter the 5-HT response. The 5-HT-induced inhibition depended on the free Ca(2+)-concentration in the pipette solution. Pretreating N x G cells with low molecular weight (LMW) heparin (160 micrograms/ml), 200 microM ryanodine or 2-10 mM caffeine attenuated the 5-HT-induced inhibition of ICa. From these results we suggest that the 5-HT-induced ICa inhibition requires release of Ca2+ from intracellular stores.
II. Physiologisches Institut, Universität des Saarlandes, Homburg/Saar, FRG.
R
R
Eckert
J
J
Utz
W
W
Trautwein
D000818:Animals; D002118:Calcium / Q000037:antagonists & inhibitors / Q000378:metabolism* / Q000502:physiology; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D015220:Calcium Channels / Q000187:drug effects / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D004594:Electrophysiology; D006822:Hybrid Cells / Q000378:metabolism; D009474:Neurons / Q000378:metabolism* / Q000502:physiology; D012701:Serotonin / Q000494:pharmacology*; D014407:Tumor Cells, Cultured
D002121:Calcium Channel Blockers; D015220:Calcium Channels; D012701:Serotonin; D002118:Calcium