Ocular torsion produced by unilateral chemical inactivation of the interstitial nucleus of Cajal in chronically labyrinthectomized cats.
Unilateral lesions of the rostral midbrain involving the interstitial nucleus of Cajal (INC) have been known to produce ocular torsion in alert animals including humans, which has been assumed to be the result of an impaired otolith-ocular reflex. We examined the effects of chemical deactivation of the INC using a gamma-aminobutyric acid (GABA) agonist (muscimol) in cats that had received bilateral labyrinthectomy, and compared the results with those in normal cats. Ocular torsion with a magnitude similar to that observed in normal cats appeared in chronically labyrinthectomized cats after unilateral muscimol infusion into the INC, indicating that ocular torsion following unilateral INC deactivation can be produced by a mechanism independent of the otolith-ocular reflex.
Fukushima
K
K
Department of Physiology, Hokkaido University School of Medicine, Sapporo, Japan.
Ohashi
T
T
Fukushima
J
J
Kase
M
M
D000818:Animals; D002415:Cats; D003714:Denervation; D007758:Ear, Inner / Q000502:physiology*; D008636:Mesencephalon / Q000187:drug effects / Q000502:physiology*; D009118:Muscimol / Q000494:pharmacology; D009135:Muscular Diseases / Q000209:etiology; D009801:Oculomotor Muscles / Q000502:physiology*; D012016:Reference Values; D013997:Time Factors; D014102:Torsion Abnormality
D009118:Muscimol