The involvement of the substantia nigra pars reticulata in hypoglycemic seizures.
Neurological complications of hypoglycemia often include seizures and fasting is a predisposing factor for seizures to occur. The mechanisms involved are unknown. In rats, insulin administration induces hypoglycemia, which may lead to generalized seizures with barrel rotations as a hallmark. Here we compared the incidence of barrel rotations in fasted and nonfasted rats. Further, we investigated the role of the substantia nigra pars reticulata (SNR) in control of barrel rotations using localized bilateral microinfusions of GABA(A) or GABA(B) receptor agonists (muscimol or baclofen, respectively) or an N-methyl-D-aspartate (NMDA) receptor antagonist (AP7). The incidence of barrel rotations was significantly higher in fasted compared to nonfasted rats. SNR infusions of muscimol were ineffective, while both baclofen and AP7 significantly decreased occurrence of barrel rotations. These data suggest that during hypoglycemia, the SNR seizure controlling system has different properties than in seizure models not involving a metabolic stress.
Velísková
Jana
J
Department of Neurology, and Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA. jvelisko@aecom.yu.edu
Chudomel
Ondrej
O
Poon
Ka Lai
KL
Marshall
Barbara
B
Velísek
Libor
L
D000818:Animals; D001418:Baclofen / Q000494:pharmacology; D001522:Behavior, Animal / Q000502:physiology; D004195:Disease Models, Animal; D005215:Fasting; D058785:GABA-A Receptor Agonists; D007003:Hypoglycemia / Q000503:physiopathology*; D008297:Male; D009118:Muscimol / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D011963:Receptors, GABA-A / Q000187:drug effects / Q000502:physiology; D016194:Receptors, N-Methyl-D-Aspartate / Q000187:drug effects / Q000502:physiology; D012640:Seizures / Q000503:physiopathology*; D013378:Substantia Nigra / Q000187:drug effects / Q000503:physiopathology*; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology / Q000502:physiology
D001418:Baclofen; D058785:GABA-A Receptor Agonists; D009118:Muscimol; D011963:Receptors, GABA-A; D016194:Receptors, N-Methyl-D-Aspartate; D005680:gamma-Aminobutyric Acid