Tyrosine and tyramine increase endogenous ganglionic morphine and dopamine levels in vitro and in vivo: cyp2d6 and tyrosine hydroxylase modulation demonstrates a dopamine coupling.

Abstract

It appears that animals have the ability to make morphine. This process also appears to be dynamic in that the inhibition of one pathway allows the other to continue with morphine synthesis. Moreover, dopamine and morphine synthesis were coupled.