Abstract

Repeated administration of subconvulsant doses of lidocaine or cocaine results in the development of an increased susceptibility to seizures induced by the two drugs (pharmacological kindling). It has been hypothesized that the local anesthetic properties of cocaine are responsible for its convulsant and epileptogenic actions. As genetic factors appear to mediate acute sensitivity to the convulsant properties of cocaine and the development of cocaine-kindled seizures, the present studies used a pharmacogenetic approach to address this question further. The convulsant effects of lidocaine were evaluated in BALB, C57, DBA and SJL mice and compared with previous studies evaluating cocaine-induced seizures. We have also evaluated the development of lidocaine- versus cocaine-kindled seizures and the effects of repeated treatment with cocaine or lidocaine on subsequent lidocaine seizure susceptibility in three of these inbred mouse strains. As observed for cocaine, genetic factors influence the convulsant properties of lidocaine; however, the differences between the strains of mice in susceptibility to lidocaine-induced seizures (SJL greater than DBA = BALB = C57) did not parallel those seen for cocaine-induced seizures (C57 greater than DBA = BALB greater than SJL). Similarly, the time course for the expression of kindled seizures and the differences between the various inbred strains were not the same for lidocaine kindling and cocaine kindling. However, depending on the genetic background of the subject, the repeated administration of lidocaine, or cocaine, resulted in the development of sensitization or tolerance to the convulsant effects of lidocaine in an identical manner.(ABSTRACT TRUNCATED AT 250 WORDS)