A pharmacological investigation of the electrically evoked convulsive activity induced by administration of catechol in the anaesthetized rat.

1 The response evoked by electrical stimulation at the wrist has been recorded from muscles of the forelimb of anaesthetized rats induced to convulse by administration of catechol.2 This response can be divided into three temporally distinct components, the characteristics of which have been described.3 The probability of occurrence of the two early components of the response has been measured before and after administration of various drugs. The results show that the first component is not affected by cholinoceptor or adrenoceptor blocking drugs or anticholinesterase agents. The probability of occurrence of the second component is significantly reduced by cholinoceptor blocking drugs and increased by physostigmine.4 The implications of these results in explaining the convulsant actions of catechol are discussed.