a lteration of pentyl enetetrazolinduced kindling parameters by pretreatment of rats with propylthiouracil and lead acetate

lead is known to be a potent neurotoxin that can cause seizure activity in humans and animals. also, epileptic type convulsion is a known complication of hypothyroidism. this study was performed to determine the effect of propylthiouracil (ptu)-induced hypothyroidism and chronic lead exposure on pentylenetetrazol (ptz)-induced kindling parameters. the test was carried out by using male albino rats weighing 180-230 g which were divided into four groups as follows: group 1: rats which received distilled water for 25 days (control group) group 2: rats pretreated with an orally administered lead acetate solution (0.05%) for 25 days group 3: rats rendered hypothyroid with ptu solution (o.i%wiv) for 25 days and group 4: rats co-treated with lead acetate solution (0.05% w iv) and ptu solution (0.1 % w iv) for 25 days. on the 26th day of the experiment ptz (ip, 30 mg/kg) was injected once a day in order to induce seizure behaviors. kindling parameters such as seizure latency, index, stage and frequency were evaluated. in animals, both lead acetate (0.05% wiv) and ptu (0.1 %wiv) pretreatment caused significant alterations in kindling parameters separately. but in animals pretreated with a combination of lead acetate and ptu, potentiation of kindling parameters was not observed compared to groups one and two. in conclusion, lead acetate and ptu may affect kindling parameters by different mechanisms.