Poster Sessions AP10: Learning,Memory and Behavior. S‐adenosylmethionine induced seizures are anesthetic dependant

S‐adenosylmethionine (SAMe) is present in all tissues and functions as the sole donor of methyl groups in over 100 different methylation reactions. Recent reports suggest that direct intraventricular injection of SAMe induces Parkinsonian like symptoms in rats including seizures, tremors, hyperkinesia and abnormal posture. In order to assess the influence of SAMe on rat behavior we have undertaken a study to examine the effect of 3 different forms of SAMe. Guide cannulae were sterotaxically implanted into the lateral ventricle of male SD rats (n = 5 for each group) using either ketamine or chloral hydrate anesthesia. 48 h post surgery the rats received a 5‐μL injection containing 1 μmol of either SAMe‐toluenedisulfonate, SAMe‐butanedisulfonate, SAMe‐chloride, or vehicle (butanedisulfonate, toluenedisulfonate or saline). Locomotor activity was monitored using the TruScan monitoring system and by videotape recording for 1 h. The videotape was reviewed by one of the authors (RD‐A) who is experienced with animal models of epilepsy. SAMe injected animals had frequent myoclonic and tonic seizures, and occasional generalized clonic seizures. SAMe induced behavioral seizures and tremors occurred only in rats that had previously been anesthetized with chloral hydrate, and not in rats that received ketamine. The number of movements recorded during the 1‐h period were significantly increased in SAMe injected animals compared to control groups in both chloral hydrate and ketamine anethetized rats. Our studies indicate that there is an anesthetic dependency for SAMe induced seizures and tremors.