Two types of calcium channels sensitive to omega-agatoxin- TK in cultured rat hippocampal neurones.
We characterized the electrophysiological properties of calcium channels in cultured rat hippocampal neurones using omega-agatoxin-TK (omega-Aga-TK) and compared them with those of the P-type channel and the BI (alpha 1A) channel which resembles the Q-type channel. Two types of omega-Aga-TK-sensitive calcium channels were detected in hippocampal neurones. The first type showed slow inactivation, high sensitivity to omega-Aga-TK and low reversibility from omega-Aga-TK-induced block, resembling the P-type channel. The second type showed fast inactivation, low sensitivity to omega-Aga-TK and high reversibility from omega-Aga-TK-induced block. These results suggest that the second type of calcium channel (Q-type-like) plays a prominent role in the hippocampal synaptic transmission.
Eisai Tsukuba Research Laboratories, Ibaraki, Japan.
T
T
Teramoto
T
T
Niidome
T
T
Miyagawa
Y
Y
Nishizawa
K
K
Katayama
K
K
Sawada
D060848:Agatoxins; D000818:Animals; D000831:Animals, Newborn; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D015220:Calcium Channels / Q000187:drug effects*; D002478:Cells, Cultured / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D018698:Glutamic Acid / Q000494:pharmacology; D006624:Hippocampus / Q000187:drug effects*; D011689:Purkinje Cells / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar; D013111:Spider Venoms / Q000494:pharmacology*; D013997:Time Factors
D060848:Agatoxins; D002121:Calcium Channel Blockers; D015220:Calcium Channels; D013111:Spider Venoms; C083855:omega-agatoxin-Aa4b; D018698:Glutamic Acid