RT Journal Article SR Electronic T1 Modification of electroshock convulsive responses and thresholds in neonatal rats after brain monoamine reduction. JF Journal of Pharmacology and Experimental Therapeutics JO J Pharmacol Exp Ther FD American Society for Pharmacology and Experimental Therapeutics SP 81 OP 90 VO 206 IS 1 A1 E D London A1 G G Buterbaugh YR 1978 UL http://jpet.aspetjournals.org/content/206/1/81.abstract AB Modification of electroshock (60 Hz; a.c.) convulsive responses and thresholds by monoamine-reducing drugs was investigated in developing rats. Throughout postnatal development, tetrabenazine (TBZ) reduced brain monoamines and increased the severity of motor responses to electroshock. The predominant maximal response in control pups progressed from hyperkinesia (day 1) to clonic convulsions (day 3) and tonic forelimb (day 7) and hindlimb (day 19) extension. The pattern in TBZ-treated pups progressed from tonic forelimb extension (day 1) to tonic hindlimb extension (day 7). On day 7, TBZ reduced the thresholds for clonic (CT) and tonic convulsions (TT) to 41 and 24% of control, respectively. Reserpine (1.25 mg/kg, 24 hours) decreased the TT but not the CT; TBZ, 4 hours before reserpine, prevented this decrease. A higher dose of reserpine (2.5 mg/kg) decreased both the CT and TT. On day 8, TBZ (25 mg/kg, 4 hours) decreased the TT (46% control); L-dihydroxyphenylalanine, but not 5-hydroxytryptophan prevented this decrease. Intracisternal 6-hydroxydopamine reduced the TT on day 8, while intracisternal 5,7-dihydroxytryptamine had no effect despite a 46% reduction in serotonin. The results indicate that in the neonatal rat brain, monoaminergic systems are sufficiently mature to attenuate electroshock convulsive responses, perhaps by limiting propagation of seizure discharge.