CSF and plasma amino acid levels in epilepsy and effects of antiepileptics on those levels

ABSTRACT

The CSF and plasma amino acid profile and the interplay between excitatory and inhibitory amino acids was studied in fifty-four Egyptian epileptic patients before and six months after initiation of drug therapy. Patients were classified into three groups according to the type of seizure [petit mal group n = 22, myoclonic group n = 9 and tonic-clonic group n = 23 patients]. The first two groups of patients were treated with sodium valproate, while the third group received carbamazepine. A significantly low mean gamma amino butyric acid [GABA] level was especially relevant to the petit mal group, while a significantly low mean glycine and taurine levels were especially relevant to the tonic-clonic group. On the other hand, a significantly higher aspartic acid level was especially relevant to the myoclonic group. Following treatment and seizure control, there was a significant increase in the inhibitory amino acid glycine and GABA and decrease in excitatory amino acid glutamic acid in the different epileptic groups whatever the drug used. Taurine was significantly increased in the tonic-clonic group and significantly decreased in the myoclonic group following seizure control. Also, a significant decrease in sulfur containing amino acids, branched chain amino acids together with histidine and arginine mean levels were found following drug therapy in the different groups. There is a disturbed balance between excitatory/inhibitory acid systems in epileptic patients. Different epileptic groups manifest with a special amino acid profile which may be of value in distinguishing between the three studied types of epilepsy. The mechanism of action of antiepileptic drugs aimed at regaining the balance between inhibitory/excitatory amino acids and impose a final common pathway in seizure control. The amino acid taurine is rather considered a neuromodulator than an inhibitory neurotransmitter