Archive 1995–2023

The cytochromes P450, a family of heme proteins, play an important role in the oxidation of drugs, toxins, as well as endogenous substrates, e.g. neurotransmitters. Quantitatively, the liver is the major drug metabolizing organ; however, the metabolism of drugs in the brain could modulate the pharmacological and pharmacodynamic effects of psychoactive drugs at their site of action.
Interestingly, CYP2D6 levels are higher in many brain regions of human smokers and alcoholics. CYP2D6 is expressed in brain regions and that enzyme activities correlate with protein and mRNA levels.
Constitutive expression of CYP2D6 in CNS may create a local environment of drug metabolism, which – along with the potential neurotransmitter modulation – may contribute to altered sensitivity and inter-individual variability in psychotropic drug response.