Partial 5-HT(1A) receptor agonist activity by the 5-HT(2C) receptor antagonist SB 206,553 is revealed in rats spinalized as neonates.

Modification of spinal serotonergic receptors caudal to spinal injury occurs in rats that received spinal cord transections as neonates. Evaluation of the serotonin syndrome, a group of motor stereotypies elicited by serotonergic (5-HT) agents in 5-HT-depleted animals, and open field locomotor behavior were used to assess behavioral consequences of injury and treatment. We extend these findings to show that a partial 5-HT(1A) agonist activity is revealed by the 5-HT(2C) receptor antagonist (SB 206,553) in this animal model, as measured by evaluation of serotonin syndrome behavior. Treadmill stimulation enhances this motor response, caudal to the injury, in the hindlimbs and tail. These results imply a broader modification of serotonergic receptors than previously thought and suggest a potential strategy by which serotonergic agents may enhance functional recovery following neonatal injury.