[Effect of glutamate on membrane potential and volume of the skeletal muscle fibers in rats following NO-synthase inhibition in vivo].
Cross-sectional area (CSA) of muscle fibers incubated in culture medium 199 for 3 hours dramatically increases, whereas resting membrane potential (RMP) decreases compared to "freshly-isolated" muscles. Both glutamate and sodium nitroprusside prevent these changes. MK-801, a specific inhibitor of NMDA-receptors, eliminates protective effects of glutamate on both CSA and RMP. NO-synthase inhibition in vivo promotes an increase of initial CSA and decrease of mean RMP. Under these conditions, effects of glutamate and sodium nitroprusside on CSA and RMP of denervated muscles are less obvious. It has been concluded that synaptic glutamate is able to participate in regulation of RMP and cell volume in muscle fibers through the activation of postsynaptic NMDA-receptors and muscle NO-synthase.
Khairova
P A
PA
Kazan State Medical University, 420012, Kazan, 49 Butlerov St., Russia.
Malomuzh
A I
AI
Naumenko
N V
NV
Urazaev
A Kh
AKh
D000818:Animals; D003964:Diaphragm / Q000294:innervation / Q000502:physiology; D016291:Dizocilpine Maleate / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D018698:Glutamic Acid / Q000494:pharmacology*; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D009121:Muscle Denervation; D018485:Muscle Fibers, Skeletal / Q000187:drug effects / Q000502:physiology; D018482:Muscle, Skeletal / Q000187:drug effects / Q000502:physiology*; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D020030:Nitric Oxide Donors / Q000494:pharmacology; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors*; D009599:Nitroprusside / Q000494:pharmacology; D051381:Rats; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors
D004791:Enzyme Inhibitors; D020030:Nitric Oxide Donors; D016194:Receptors, N-Methyl-D-Aspartate; D009599:Nitroprusside; D018698:Glutamic Acid; D016291:Dizocilpine Maleate; D019001:Nitric Oxide Synthase; D019331:NG-Nitroarginine Methyl Ester