Effect of repeated versus single electroconvulsive seizures on adrenergic-mediated phosphatidylinositol hydrolysis in rat neocortex.
Adrenergic-stimulated phosphatidylinositol (PI) hydrolysis was measured in cortical slices obtained from adult rats following electroconvulsive seizures (ECS). One group of animals received ECS daily for 15 days and a second group received a single ECS. Rats were then sacrificed at intervals of 15 min, 60 min, 4 h, and 24 h after the last ECS. Inositol 1-monophosphate (IP1) accumulation was transiently reduced (20%, P less than 0.01), at 15 min, in repeatedly shocked versus sham-shocked control animals. No changes were observed at later intervals nor at any time in rats submitted to a single ECS. These findings suggest that repeated but not single convulsive seizures transiently desensitize adrenergic-mediated PI metabolism. Although repeated ECS significantly increased the density (Bmax) of alpha 1 recognition sites in cortical slices at 15 min, 4 h, and 24 h, this upregulation was not coupled to a functional change in PI hydrolysis.
Dubeau
F
F
Montreal Neurological Institute, McGill University, Quebec, Canada.
Sherwin
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AL
D000818:Animals; D002540:Cerebral Cortex / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D004597:Electroshock / Q000379:methods; D004837:Epinephrine / Q000494:pharmacology; D006868:Hydrolysis; D008297:Male; D010716:Phosphatidylinositols / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D011942:Receptors, Adrenergic, alpha / Q000378:metabolism / Q000502:physiology*; D012640:Seizures / Q000209:etiology / Q000503:physiopathology*
D010716:Phosphatidylinositols; D011942:Receptors, Adrenergic, alpha; D004837:Epinephrine