Hypersensitivity to alpha-methyl-p-tyrosine suggests that behavioural recovery of rats receiving neonatal 6-OHDA lesions is mediated by residual catecholamine neurones.

Previous studies have shown that rats depleted of catecholamines (CA), and in particular dopamine (DA), as neonates are sub-sensitive to DA antagonists and do not respond to homeostatic imbalances as adults. This suggests that these animals maintain themselves independent of the DA system. If this were so, they would be insensitive to the disruption of residual CA function by treatment with the CA synthesis inhibitor alpha-methyl-p-tyrosine (alpha-MT). By contrast, rats that received neonatal injections of the neurotoxin 6-hydroxydopamine (6-OHDA) showed a marked increase in sensitivity to alpha-MT when tested as adults. This suggests that they remain dependent upon residual CA neurones for the maintenance of normal eating.