Modulation by nitric oxide (NO) of the intensity of non-quantum mediator secretion in neuromuscular junctions in rats.
Experiments on rat diaphragm muscle showed that the nitric oxide (NO) donors sodium nitroprusside SNP) and S-nitroso-N-acetylpenicillamine (SNAP). as well as L-arginine. a substrate for NO synthesis. decreased the level of muscle fiber hyperpolarization (the H effect) after blockade of cholinoceptors on the postsynaptic membrane by d-tubocurarine in conditions of irreversible inhibition of acetylcholinesterase with armine. Conversely, disruptions to NO synthesis in muscle fibers by the NO synthase blocker NG-nitro-L-arginine methyl ester (L-NAME) led to increases in the H effect both in vitro and in vivo. Inactivated solutions of sodium nitroprusside and inactive forms of arginine and NAME (D-arginine. D-NAME) had no effect on the magnitude of the H effect, while hemoglobin, which efficiently binds NO molecules, blocked the inhibitory effects of sodium nitroprusside. SNAP, and L-arginine on the magnitude of the H effect. All these points provide evidence that NO can function as a modulator of non-quantum mediator release in the neuromuscular junctions of warm-blooded animals.
Mukhtarov
M R
MR
Kazan Institute of Biochemistry and Biophysics, Russian Academy of Sciences.
Urazaev
A K
AK
Nikolskii
E E
EE
Vyskocil
F
F
D000109:Acetylcholine / Q000378:metabolism; D000818:Animals; D004791:Enzyme Inhibitors / Q000494:pharmacology; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects; D005110:Extracellular Space / Q000502:physiology; D066298:In Vitro Techniques; D008564:Membrane Potentials / Q000187:drug effects; D009046:Motor Neurons / Q000502:physiology; D018482:Muscle, Skeletal / Q000294:innervation / Q000502:physiology; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009411:Nerve Endings / Q000502:physiology; D009469:Neuromuscular Junction / Q000378:metabolism / Q000502:physiology*; D018377:Neurotransmitter Agents / Q000378:metabolism / Q000502:physiology*; D009569:Nitric Oxide / Q000096:biosynthesis / Q000502:physiology*; D020030:Nitric Oxide Donors / Q000494:pharmacology; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D052250:Nitric Oxide Synthase Type III; D051381:Rats; D013569:Synapses / Q000187:drug effects / Q000502:physiology
D004791:Enzyme Inhibitors; D018377:Neurotransmitter Agents; D020030:Nitric Oxide Donors; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D052250:Nitric Oxide Synthase Type III; C496316:Nos3 protein, rat; D000109:Acetylcholine; D019331:NG-Nitroarginine Methyl Ester