The effects of some polyamines on putative behavioural indices of mesolimbic versus striatal dopaminergic function.

The presence of polyamines in the brain, together with the previous reports of a structural similarity with neuroleptics, has led to the hypothesis that polyamines may have a modulatory role in the control of cerebral dopamine function. In this study, the effects of two polyamines, spermine and spermidine, were therefore tested on indices of dopamine-mediated behaviour in rats and mice. Spermine and spermidine caused a dose-dependent inhibition of mouse spontaneous climbing behaviour and wheel running at doses between 5 and 40 mg/kg IP but failed to cause catalepsy in the rat or to antagonise the stereotyped behaviour induced by apomorphine. When polyamines were given by intracerebral injection a similar regional selectivity was seen. Both spermine and spermidine (5-20 micrograms) when given bilaterally into the nucleus accumbens inhibited the hyperactivity caused by amphetamine injected into the same nucleus. However, when injected into the rat corpus striatum, neither polyamine was able to initiate any asymmetry or circling either spontaneously or after apomorphine injection IP. These results indicated a selective action of polyamines on mesolimbic dopamine behaviour. Possible implications for the understanding of psychosis and future work are suggested.