Effects of neonatal clomipramine on cholinergic receptor sensitivity and passive avoidance behavior in adult rats.

The effects of neonatal treatment with clomipramine on the sensitivity of cholinergic receptor and passive avoidance behavior were studied to examine the activity of the central cholinergic system. Rat pups were treated twice daily from postnatal day 5 to 21 with clomipramine (15 mg/kg, s.c.) and at 3 months of age the thermic responses to three different doses of oxotremorine were measured. One day following oxotremorine challenge study, the animals were subjected to passive avoidance training and retention was measured 24-hr later. Clomipramine treated animals showed an enhanced cholinomimetic-induced hypothermia and an increased latency in passive avoidance test. These findings may reflect an altered sensitivity of central cholinergic system in rats given clomipramine as neonates. The results were compared to other animal models of depression.