Suppressive effects of L-5-hydroxytryptophan in a feline model of photosensitive epilepsy.
We recently demonstrated that long-lasting photosensitivity is acquired as a result of kindling of the lateral geniculate nucleus (LGN), and that the LGN-kindled cat pretreated with D, L-allylglycine represents a useful model of epilepsy for drug studies. The present experiments studied anticonvulsant effects of a serotonin precursor, L-5-hydroxytryptophan (5-HTP), on photosensitivity in the LGN-kindled cat under D,L-allylglycine and on LGN-kindled seizures. 5-HTP suppressed both myoclonic responses and paroxysmal EEG discharges induced by photic stimulation in a dose-related manner. Photically-induced seizures were completely blocked 1.5-2 h after injection of 20 mg/kg 5-HTP. 5-HTP was also effective in reducing the afterdischarge duration and behavioral seizure stage in LGN-kindled seizures; following 40 mg/kg administration, no electroclinical seizures were elicited in the LGN-kindled cats. Serotonergic mechanisms may play an important role in epileptic photosensitivity; the 5-HTP suppressive effect on photosensitivity is at least partly due to reduced neuronal activity at the level of the LGN via serotonergic inhibition.
Wada
Y
Y
Department of Neuropsychiatry, Kanazawa University School of Medicine, Japan.
Hasegawa
H
H
Nakamura
M
M
Yamaguchi
N
N
D006916:5-Hydroxytryptophan / Q000494:pharmacology* / Q000627:therapeutic use; D000501:Allylglycine / Q000494:pharmacology; D000818:Animals; D002415:Cats; D004558:Electric Stimulation; D004569:Electroencephalography / Q000187:drug effects; D005260:Female; D005829:Geniculate Bodies / Q000187:drug effects / Q000502:physiology / Q000503:physiopathology*; D006624:Hippocampus / Q000187:drug effects / Q000502:physiology / Q000503:physiopathology*; D007696:Kindling, Neurologic; D008297:Male; D010775:Photic Stimulation; D012154:Reticular Formation / Q000187:drug effects / Q000502:physiology / Q000503:physiopathology*; D012640:Seizures / Q000209:etiology / Q000503:physiopathology* / Q000517:prevention & control
D000501:Allylglycine; D006916:5-Hydroxytryptophan