title: A comparative study of L-type voltage sensitive Ca2+ channels in rat brain regions and cultured neuronal cells.
abstract: Radioligand binding studies using the L-type voltage sensitive Ca2+ channel (VSCC) antagonist (+)-[3H]PN200-110 revealed the following rank order channel density in rat brain and cultured neuronal cell homogenates: striatum > or = cerebrocortex > > cerebellum = brainstem > SH-SY5Y cell line > NG108-15 cell line > 1321N1 cell line > PC12 cell line. There were no significant differences in the equilibrium dissociation constant, Kd for (+)-[3H]PN200-110 or pK50 for nifedipine. K+ depolarization in SH-SY5Y cells and NG108-15 cells evoked a biphasic and monophasic increase in [Ca2+]i. The L-type Ca2+ channel antagonist nifedipine (1 microM) produced a 66 and 87% inhibition of the K(+)-evoked rise in the peak and plateau phase [Ca2+]i in SH-SY5Y cells and abolished the monophasic response in NG108-15 cells. The L-channel activator S(-)Bay K 8644 (1 microM) enhanced the K(+)-evoked increase in [Ca2+]i in both cell lines. These data demonstrate a comparatively low density of L-VSCC in undifferentiated SH-SY5Y cells, NG108-15 cells, 1321N1 cells and PC12 cells that are functionally active in at least SH-SY5Y cells and NG108-15 cells.
authors.affiliation: University Department of Anaesthesia, Leicester Royal Infirmary, UK.
authors.forename: K
authors.initials: K
authors.lastname: Hirota
authors.forename: D G
authors.initials: DG
authors.lastname: Lambert
mesh_terms: D000818:Animals; D001921:Brain / Q000166:cytology / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism; D002121:Calcium Channel Blockers / Q000378:metabolism / Q000494:pharmacology; D015220:Calcium Channels / Q000378:metabolism* / Q000502:physiology*; D004594:Electrophysiology; D005260:Female; D007425:Intracellular Membranes / Q000378:metabolism; D017275:Isradipine / Q000378:metabolism; D009474:Neurons / Q000378:metabolism*; D009543:Nifedipine / Q000494:pharmacology; D009994:Osmolar Concentration; D016716:PC12 Cells; D011188:Potassium / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D014407:Tumor Cells, Cultured
chemical_list: D002121:Calcium Channel Blockers; D015220:Calcium Channels; D009543:Nifedipine; D011188:Potassium; D002118:Calcium; D017275:Isradipine