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Kv7/KCNQ/M and HCN/ h , but not KCa2/SK channels, contribute to the somatic medium after- hyperpolarization and excitability control in CA1 hippocampal pyramidal cells. J Physiol 566.3 (2005) pp 689–715. Theories of mAHP Generation. Previously: M-Channels (Depolarized Potentials)
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Kv7/KCNQ/M and HCN/h, but not KCa2/SK channels, contribute to the somatic medium after-hyperpolarization and excitability control in CA1 hippocampal pyramidal cells J Physiol 566.3 (2005) pp 689–715
Theories of mAHP Generation • Previously: • M-Channels (Depolarized Potentials) • h-Channels (Polarized Potentials) • Not SK channels • Recently: • Mainly by SK channels OR • Only by h-channels
M-Channels • XE991 (M-Channel Blocker) • At -60mV • Suppressed mAHP • Enhanced excitability • Reduced frequency adaptation • Enhanced afterdepolarization • Promoted bursting • Little effect on mAHP at -80mV
M-Channels • Retigabine (M-Channel Opener) • Reduced excitability
h-Channels • ZD7288 (h-Chanel Blocker) • At -80mV • Fully suppressed mAHP • Increased excitability • No effect on mAHP at -60mV
Ca2+-activated K+ Channels (SK/Kca) • Apamin (SK/Kca Blocker) • No effect on mAHP • Forskolin (AdenylylCyclase Activator) • Ca2+ free medium • Replaced by Mn2+
Conclusions • M- / h-Channels generate mAHP • M-Channels at -60mV • h-Channels at -80mV • SK Channels do not contribute to mAHP