Timing of 6-hydroxydopamine administration influences its effects on visual cortical plasticity.
We recorded from the visual cortex of 4 groups of monocularly deprived kittens. Three groups were treated with intraventricular 6-hydroxydopamine (6-OHDA) at different times relative to monocular deprivation (MD). One group received only vehicle solution and MD. 6-OHDA caused the greatest decrease in plasticity in the kittens receiving 6-OHDA throughout the deprivation period; that is, these kittens were the least affected by MD. 6-OHDA caused a smaller decrease in plasticity in kittens receiving 6-OHDA just prior to eyelid suture and a still smaller decrease in kittens waiting a week between 6-OHDA treatment and eyelid suture. The kittens in all groups receiving 6-OHDA were equally depleted of norepinephrine (NE). We conclude that 6-OHDA decreases plasticity in the visual cortex; however, the time course of this decrease is better related to the time course of the 6-OHDA treatment than to the time course of NE depletion.
D000367:Age Factors; D000818:Animals; D002415:Cats; D006892:Hydroxydopamines / Q000494:pharmacology*; D007276:Injections, Intraventricular; D009473:Neuronal Plasticity / Q000187:drug effects*; D009638:Norepinephrine / Q000502:physiology*; D016627:Oxidopamine; D012683:Sensory Deprivation / Q000502:physiology*; D014785:Vision, Ocular / Q000502:physiology*; D014793:Visual Cortex / Q000187:drug effects* / Q000503:physiopathology
D006892:Hydroxydopamines; D016627:Oxidopamine; D009638:Norepinephrine