Biochemical compensation and recovery following temporary inhibition of ornithine decarboxylase during the development of rat cerebellar cortex

Abstract

Specific inhibition of ornithine decarboxylase selectively in the developing rat cerebellum was achieved within 10 min after intrathecal injection of α-difluoromethylornithine. Twelve hours later the activity started to increase, passed control levels between 2 and 3 days, continued to increase and reached its peak values by day 3 (when animals were 10 days old), 3 days after peak control values. Ornithine decarboxylase activity then declined and attained low adult values simultaneously with controls. Glutamic acid decarboxylase activity, a marker of gabaergic neurons maturation, declined to a nadir at 3 days postinjection, and then was elevated transiently above control levels with a peak at 11 days postinjection. We conclude that after such a temporary insult neuroblasts of the cerebellar cortex are capable of full recovery, which is apparent by a reversible reduction in ornithine decarboxylase and glutamic acid decarboxylase activities followed by a transient compensatory elevation in both enzymes.