Increase of GABA receptor binding activity after short lasting monocular deprivation in kittens

GABA receptor activity, as measured by [3H]muscimol binding, was investigated in visual and auditory cortex of 5 weeks old kittens with different visual experience. Binocular deprivation since birth did not affect the GABA receptor binding activity. Three days of monocular vision resulted in an increase of [3H]muscimol binding in the visual cortex of both normally reared (144 percent) and binocularly deprived kittens (149 percent). Neither 3 days of normal binocular vision in deprived animals nor 3 days of binocular deprivation in normally reared ones produced significant changes in GABA receptor binding activity. In all experimental conditions [3H]muscimol binding in auditory cortex was similar. We suggest that activation of the GABA-ergic system is due to asymmetric visual input, possibly connected with mechanisms of ocular dominance shift.