The effect of somatostatin on striatal catecholamines.

Somatostatin and several analogues were injected into rat striatum and their effects on dopamine, serotonin and their metabolites were examined at 1 h. Somatostatin induced a dose-dependent increase in dopamine turnover in the ipsilateral striatum accompanied by a reduction in turnover on the contralateral side. There was no effect on serotonin turnover. Long-acting somatostatin analogues (D-Trp-8-somatostatin, SMS-201-995) had similar effects. These results suggest that somatostatin is involved in local regulation of striatal dopaminergic transmission and that it plays a role in regulation of dopamine release in the contralateral striatum.