Corticotropin-releasing factor activates tyrosine hydroxylase in rat and mouse striatal homogenates

Corticotropin-releasing factor (CRF) caused a concentration-dependent increase in dopamine (DA) synthesis measured in rat striatal synaptosomes. The concentrations of CRF producing half-maximal and maximal stimulation were 40 and 300 nM, respectively. The maximal effect corresponded to a 34% increase from the control level of DA synthesis. CRF 1 microM increased DA synthesis in synaptosomes of mouse striatum by 48%. Pretreatment of striatal synaptosomes with CRF produced a persistent activation of tyrosine hydroxylase assayed in extracts of lysed synaptosomes. These results suggest that CRF may play a modulatory role in striatal DA synthesis by acting on receptors located on DA terminals.