Anxiolytic-like behavior in rats is induced by the neonatal intracranial injection of apotransferrin

To determine whether neonatal intracranial injection of apotransferrin (aTf ), which increases myelin deposition, has behavioral effects in rats, 3-day -old rats were intracranially injected with 350 ng of aTf and tested at 25 and 60 days of age. An anxiolytic-like behavior was observed in aTf-treated rats, evidenced by an increase in the exploration of open arms in the plus maze test without changes in the locomotor activity. This behavioral profi le persists until adulthood. Intraperitoneal injection of 0.75 mg/kg of pic rotoxin, a GABA, receptor channel antagonist, abolished this anxiolytic-lik e behavior, indicating that neonatal aTf induces a long-lasting increase in GABA, receptor functionality. (C) 2001 Wiley-Liss, Inc.