Increased tyrosine availability increases brain regional DOPA levels in vivo

► We examined how l-tyrosine availability affects DOPA levels. ► l-tyrosine and NSD-1015 were introduced by reverse dialysis. ► l-tyrosine elevated DOPA accumulation in striatum and medial prefrontal cortex. ► Tyrosine hydroxylase activity may not always be rate-limiting for catecholamine synthesis.