Time course of receptor-channel coupling in frog sympathetic neurons.
The M-type potassium current and the N-type calcium current are inhibited by several different neurotransmitters in frog sympathetic neurons. These effects seem to be mediated via G proteins, but it is not clear whether diffusible second messengers are involved. Using a rapid (approximately 100 ms) flow tube perfusion system to apply agonists, the inhibition of calcium current develops and recovers rapidly but not instantaneously (t1/2 = 1-2 s). M-current inhibition is considerably slower, with t1/2 approximately 30 s for recovery from inhibition. At least for M-current inhibition, there appears to be sufficient time for involvement of an enzymatic cascade in receptor-channel coupling.
Jones
S W
SW
Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, Ohio 44106.
D000818:Animals; D055592:Biophysical Phenomena; D001703:Biophysics; D015220:Calcium Channels / Q000187:drug effects / Q000378:metabolism; D004563:Electrochemistry; D007987:Gonadotropin-Releasing Hormone / Q000494:pharmacology; D066298:In Vitro Techniques; D007473:Ion Channels / Q000187:drug effects / Q000378:metabolism*; D007700:Kinetics; D009474:Neurons / Q000378:metabolism*; D018377:Neurotransmitter Agents / Q000494:pharmacology; D015221:Potassium Channels / Q000187:drug effects / Q000378:metabolism; D011892:Rana catesbeiana; D017981:Receptors, Neurotransmitter / Q000187:drug effects / Q000378:metabolism*; D015290:Second Messenger Systems / Q000187:drug effects / Q000502:physiology; D013564:Sympathetic Nervous System / Q000378:metabolism
D015220:Calcium Channels; D007473:Ion Channels; D018377:Neurotransmitter Agents; D015221:Potassium Channels; D017981:Receptors, Neurotransmitter; D007987:Gonadotropin-Releasing Hormone