The GABAergic nigro-collicular pathway is not involved in the inhibitory control of audiogenic seizures in the rat.
Involvement of the GABAergic nigro-collicular pathway in the control of audiogenic seizures was examined in genetically sensitive rats by studying the effects of bilateral injections into the substantia nigra of muscimol, a gamma-Aminobutyric acid (GABA) agonist, and those of bilateral injections into the superior colliculus of picrotoxin, a GABA antagonist, and of muscimol. Microinjections of muscimol (20-80 ng/side) into the substantia nigra and microinjections into the superior colliculus of picrotoxin (20 and 40 ng/side) both failed to suppress audiogenic seizures. Following injections into the superior colliculus, audiogenic seizures were in fact facilitated by picrotoxin and suppressed by muscimol. These results suggest that the nigro-collicular GABAergic pathway is not involved in the inhibitory control over audiogenic seizures. Conversely, a different GABAergic mechanisms may be involved in the superior colliculus in the control of this form of epilepsy.
Depaulis
A
A
Departement de Neurophysiologie et Biologie des Comportements, CNRS, Strasbourg, France.
Marescaux
C
C
Liu
Z
Z
Vergnes
M
M
D000161:Acoustic Stimulation; D000818:Animals; D008297:Male; D008845:Microinjections; D009118:Muscimol / Q000494:pharmacology*; D009434:Neural Pathways / Q000187:drug effects*; D010852:Picrotoxin / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D012640:Seizures / Q000503:physiopathology*; D013378:Substantia Nigra / Q000187:drug effects*; D013477:Superior Colliculi / Q000187:drug effects*
D009118:Muscimol; D010852:Picrotoxin