Evidence that L-arginine possesses proconvulsant effects mediated through nitric oxide.
Increasing evidence suggests a neurotransmitter role for NO in the mammalian CNS. We have now studied the behavioural and electrocortical (ECoG) profile of rats injected into the lateral cerebral ventricle (ICV) with L-arginine (L-arg), the endogenous donor of the guanidino group from which NO physiologically originates. Rats treated with L-arg (up to 300 micrograms) showed behavioural stimulation, ECoG desynchronization with occasional isolated high voltage spikes but not motor seizures. In rats receiving a subconvulsive dose (0.5 microgram) of N-methyl-D-aspartic acid, (NMDA; ICV) the microinjection of L-arg (300 micrograms; 1 min before) resulted in behavioural and ECoG seizures. The latter effects were prevented by co-administrating L-arg with N-nitro-L-arginine (L-NAME), an inhibitor of NO synthesis. In conclusion, L-arg possesses proconvulsant effects probably mediated by an increase in NO synthesis.
Mollace
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Department of Biology, University of Rome, Tor Vergata, Italy.
Bagetta
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Nisticò
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D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives / Q000494:pharmacology*; D001522:Behavior, Animal / Q000187:drug effects; D003292:Convulsants; D004562:Electrocardiography; D005106:Exploratory Behavior / Q000187:drug effects; D007276:Injections, Intraventricular; D008297:Male; D009043:Motor Activity / Q000187:drug effects; D016202:N-Methylaspartate / Q000494:pharmacology; D009569:Nitric Oxide; D019335:Nitroarginine; D051381:Rats; D011919:Rats, Inbred Strains; D013238:Stereotaxic Techniques
D003292:Convulsants; D019335:Nitroarginine; D009569:Nitric Oxide; D016202:N-Methylaspartate; D001120:Arginine