Anticonvulsant effects of restraint and pyridoxine on hydrazine seizures in the monkey.

Abstract This study compared convulsive and related preconvulsive responses to monomethylhydrazine (MMH) in three groups of chaired rhesus monkeys. One group served as a control and the other two as experimental groups to evaluate the influence on these measures of arm restraint and pyridoxine, respectively. Control animals displayed emesis, preictal responses, and generalized seizures within the first 75 min after MMH injection. Pyridoxine-treated animals showed emesis but no preictal or ictal behavior during this period, and arm-restrained animals showed no emesis, preictal, or ictal behavior. Control animals exhibited a criterion of three generalized seizures, after which chemotherapy was administered, within the first 100 min after MMH injection. Neither pyridoxine-treated nor arm-restraint animals showed any generalized seizures during a standard 240-min observation period, although both groups eventually displayed emesis and preictal responses. The protective effects of pyridoxine were interpreted within the context of established neurochemical influences of the hydrazines on synthesis of the inhibitory neurotransmitter, gamma-aminobutyric acid. The protective effect of restraint was related to similar observations in the literature and discussed in terms of central nervous system activation, inhibitory neurotransmitter dynamics, and correlated somatosensory electroencephalogram patterns indicative of an anticonvulsant “immobilization state”.