Different distribution of nifedipine- and omega-conotoxin GVIA-sensitive Ca2+ channels in rat hippocampal neurons.
The distribution patterns of nifedipine- and omega-conotoxin GVIA-sensitive Ca2+ channels in rat primary cultured hippocampal neurons were investigated with a confocal laser-scanning microscope. Cells were loaded with the calcium indicator dye Oregon Green/AM, and the responses to high potassium (90 mM) solution with and without the existence of L- and N-type Ca2+ channel blockers were imaged. In general, extracellular application of high [K+] solution induced a [Ca2+]o-dependent increase of [Ca2+]i in both somata and dendritic processes. The increase was reduced by a N-type channel blocker, omega-conotoxin GVIA, and the reduction was greater in dendritic processes than in somata and proximal dendrites. In contrast, the reduction induced by the L-type calcium channel blocker, nifedipine, was observed evenly all over the neurons. The results demonstrated the heterogeneous distribution of nifedipine- and omega-conotoxin GVIA-sensitive calcium channels in cultured hippocampal neurons.
Wang
G
G
Department of Bioengineering, Faculty of Engineering, Kagoshima University, Japan.
Ding
S
S
Yunokuchi
K
K
D000818:Animals; D015220:Calcium Channels / Q000187:drug effects* / Q000378:metabolism; D048429:Cell Size / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D003712:Dendrites / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D005333:Fetus; D005452:Fluoresceins / Q000494:pharmacology; D005456:Fluorescent Dyes / Q000494:pharmacology; D006624:Hippocampus / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D009474:Neurons / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D009543:Nifedipine / Q000494:pharmacology*; D011188:Potassium / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D020866:omega-Conotoxin GVIA / Q000494:pharmacology*
D015220:Calcium Channels; D005452:Fluoresceins; D005456:Fluorescent Dyes; C401939:oregon green 514; D020866:omega-Conotoxin GVIA; D009543:Nifedipine; D011188:Potassium