Neonatal 6-hydroxydopamine lesion of spinal norepinephrine terminals fails to affect the ontogeny of swimming behavior.

Newborn rats were injected either systemically or intraspinally with 6-hydroxydopamine. Both treatments drastically reduced spinal norepinephrine (NE), while the former also reduced forebrain NE. Spinal NE loss did not affect the ontogeny or the adult expression of swimming, a sensitive test of complex patterned locomotion. Spinal NE is not essential to either the ontogeny of complex motor behavior or to the generation of such behavior in adult rats.