Luteinizing hormone-releasing hormone modulates nicotinic ACh-receptor sensitivity in amphibian cholinergic transmission.
Luteinizing hormone-releasing hormone (LH-RH; 100 nM-50 microM) reduced the sensitivity of the nicotinic ACh-receptor in amphibian sympathetic ganglion cells and skeletal muscle end-plates. Analyses of LH-RH action, based on a Michaelis-Menten type kinetics, revealed that LH-RH depressed the maximum response (Vmax) of the dose-response curve of ACh currents without changing the affinity (Km) of ACh to the receptor. It was suggested that LH-RH reduced the sensitivity of nicotinic receptor by acting on a certain allosteric site of the receptor-ionic channel complex. Probably, LH-RH reduces the ACh current by decreasing the number of channels available.
D000818:Animals; D004305:Dose-Response Relationship, Drug; D005728:Ganglia, Sympathetic / Q000187:drug effects*; D007987:Gonadotropin-Releasing Hormone / Q000494:pharmacology*; D008564:Membrane Potentials / Q000187:drug effects; D009045:Motor Endplate / Q000187:drug effects*; D009469:Neuromuscular Junction / Q000187:drug effects*; D011898:Ranidae; D011950:Receptors, Cholinergic / Q000187:drug effects*; D012584:Sciatic Nerve / Q000187:drug effects; D009435:Synaptic Transmission / Q000187:drug effects*
D011950:Receptors, Cholinergic; D007987:Gonadotropin-Releasing Hormone