Possible involvement of a central noradrenergic system in automutilation induced by clonidine in mice.

Automutilation induced by a single large dose of clonidine was potentiated by pretreatment with methamphetamine, caffeine and theophyline, while it was inhibited by acute administration of reserpine, alpha-methyl-p-tyrosine, phenoxybenzamine, phentolamine and chlorpromazine. L-Dopa, 5-hydroxytryptophan and p-chlorophenylalanine had no effect on this abnormal behavior. Biochemical studies on brain monoamines revealed that noradrenaline was markedly increased and dopamine slightly so, but 5-hydroxytryptamine was never changed by clonidine. These results suggest that a central noradrenergic system may be involved in automutilation induced by clonidine in mice.