Effects of L-arginine on picrotoxin-induced increase in brain ammonia concentrations and convulsions in rats.
The effect of L-arginine (840 mg/kg) pre- (30 min before challenge) and post-treatment (5 min after challenge) period was tested on picrotoxin-induced increase in ammonia concentrations in brain regions (cerebral cortex, brain stem and cerebellum) and the accompanying convulsive responses in adult male rats. The combined effect of L-arginine and diazepam was also tested against picrotoxin-induced convulsions. Picrotoxin-induced increase in ammonia was reverted partially by L-arginine pretreatment. However, L-arginine pretreatment did not show anticonvulsant effect independently or concurrently with diazepam. On the other hand, L-arginine post-treatment reverted ammonia to control level in all brain regions. A partial but significant inhibition of convulsion responses was found in these animals. The combined effect of diazepam and L-arginine post-treatment was much greater than that produced by these agents independently. These findings suggest that ammonia has a partial but significant participation in the convulsant action of picrotoxin. L-arginine has a potential to revert brain ammonia to control level in picrotoxin-treated animals and thereby it has produced a partial protection. The data further indicate that the duration of action of L-arginine is considerably short and has an additive anticonvulsant action with diazepam.
Paul
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Department of Pharmacology & Environmental Toxicology, Dr. A. L. M. Postgraduate Institute of Basic Medical Sciences, University of Madras, Taramani, Chennai.
Jayakumar
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AR
D000641:Ammonia / Q000378:metabolism*; D000818:Animals; D000927:Anticonvulsants / Q000008:administration & dosage / Q000494:pharmacology; D001120:Arginine / Q000008:administration & dosage / Q000494:pharmacology*; D001921:Brain / Q000187:drug effects* / Q000378:metabolism*; D001933:Brain Stem / Q000378:metabolism; D002531:Cerebellum / Q000378:metabolism; D002540:Cerebral Cortex / Q000378:metabolism; D003975:Diazepam / Q000008:administration & dosage / Q000494:pharmacology; D008297:Male; D010852:Picrotoxin / Q000633:toxicity*; D051381:Rats; D017208:Rats, Wistar; D012640:Seizures / Q000139:chemically induced* / Q000378:metabolism / Q000517:prevention & control*; D014018:Tissue Distribution; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
D000641:Ammonia; D000927:Anticonvulsants; D001120:Arginine; D003975:Diazepam; D010852:Picrotoxin; D005680:gamma-Aminobutyric Acid