Effects of ethylenediamine in rodent models of seizure, motor coordination and anxiety.

Ethylenediamine (EDA) activates GABAA receptors via both direct and indirect mechanisms. EDA has been shown to reduce seizures caused by systemic injection of proconvulsants in an animal model of generalized tonic–clonic seizures. However, there does not appear to have been any report on the effects of EDA in other seizure models. Hence, we used male Sprague-Dawley rats to test the effects of EDA on topically applied bicuculline (a model of simple partial seizures) and on maximal electroshock (MES, a model of generalized tonic–clonic seizures). We also examined the effects of EDA on motor coordination using a rotarod treadmill, and its potential anxiolytic properties using an elevated plus maze (EPM). EDA at concentrations of 50μM and above reduced the frequency of epileptiform spikes on an electrocorticogram in a concentration-dependent manner. EDA at 100 and 1000mg/kg i.p. increased the threshold for inducing limb extension on the MES. EDA did not affect the time spent by rats on the rotarod at 10 or 100mg/kg, but significantly reduced the time spent at doses of 1000mg/kg. In the EPM, EDA at 10 or 100mg/kg significantly increased the frequency of entries and time spent in the open arms. We conclude that EDA has antiepileptic and anxiolytic activity at doses that do not affect motor coordination.