Modulation by nitric oxide (NO) of the intensity of non-quantum mediator secretion in neuromuscular junctions in rats

• Published in: Neuroscience and behavioral physiology 2001-07, Vol.31 (4), p.451-455
• Main Authors: Mukhtarov, M R, Urazaev, A K, Nikolskii, E E, Vyskocil, F
• Format: Article
• Language: English
• Subjects: Acetylcholine - metabolism; Animals; Enzyme Inhibitors - pharmacology; Excitatory Postsynaptic Potentials - drug effects; Extracellular Space - physiology; In Vitro Techniques; Membrane Potentials - drug effects; Motor Neurons - physiology; Muscle, Skeletal - innervation; Muscle, Skeletal - physiology; Nerve Endings - physiology; Neuromuscular Junction - metabolism; Neuromuscular Junction - physiology; Neurotransmitter Agents - metabolism; Neurotransmitter Agents - physiology; NG-Nitroarginine Methyl Ester - pharmacology; Nitric Oxide - biosynthesis; Nitric Oxide - physiology; Nitric Oxide Donors - pharmacology; Nitric Oxide Synthase - antagonists & inhibitors; Nitric Oxide Synthase Type III; Rats; Synapses - drug effects; Synapses - physiology
• ISSN: 0097-0549; 1573-899X
• DOI: 10.1023/A:1010453031902

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.