The effect of harmaline on seizures induced by amygdala kindling in rats

Objective: Harmaline and other beta-carbolines act as an inverse agonist for GABA-A receptors and cause central nervous system stimulation and anxiety; thus, it may act hypothetically as a potential seizure augmenter. To examine the hypothesis, the effect of harmaline during the seizures induced by amygdala kindling is investigated here.Methods: Seven groups of male rats were kindled by daily electrical stimulation of the amygdala. After being kindled, Groups I-III, respectively, received 5, 15 and 50mg/kg harmaline through intraperitoneal injection. The rats in Groups IV and V received vehicle daily (1ml/kg) and harmaline (5mg/kg) daily through intraperitoneal injection. Groups VI and VII received artificial cerebrospinal fluid and harmaline (50mM) through intraventricular injection, respectively.Results: In addition to significant increase of some seizure parameters in the fully kindled groups, harmaline significantly increased cumulative afterdischarge duration (P<0.05) and decreased stage 1 latency (P<0.01) in the acquisition groups (Groups V and VII). In Group VII, seizure duration showed a significant increase (P<0.01) while stage 1 latency and stage 4 latency decreased significantly (P<0.01).Discussion: According to the results, it is suggested that harmaline may increase neuronal activity and the production of high-frequency action potentials by stimulating NMDA receptors and inhibiting GABA receptors. Overall, drugs and plants containing harmaline may be harmful to epileptic-susceptible people during some traditionally and costume treatments, so theseshould be avoided.