The regulation of striatal DOPA synthesis by alpha 2-adrenoreceptors.

The administration of alpha 2-adrenoreceptor antagonists SKF 64139 or SKF 72223 (TIQ derivatives) elicits an increase in striatal DOPA synthesis. The findings that the enhanced DOPA synthesis is reversed by pretreatment of the animals with clonidine or with the D beta H inhibitor FLA-63 suggest that action of the TIQ derivatives is related to their ability to block alpha-adrenoreceptors. It is being postulated that the enhanced striatal DOPA synthesis elicited by the TIQ derivatives is a result of inhibition of dopaminergic neurotransmission.