A comparison of the neurochemical properties of the stereoisomers of tranylcypromine in the central nervous system
Hampson, D.R.; Baker, G.B.; Coutts, R.T.
Cellular and Molecular Biology 32(5): 593-599
1986
ISSN/ISBN: 0145-5680 PMID: 3779760 Document Number: 277569
A number of neurochemical and neuropharmacological properties of the stereoisomers of the antidepressant tranylcypromine (TCP) were investigated in vivo and in vitro. Properties studied included inhibition of MAO-A and MAO-B, effects on brain levels of 5-hydroxytryptamine (5-HT) and .beta.-phenethylamine (PEA) (specific substrates for MAO-A and MAO-B, respectively), brain levels of the TCP isomers, and effects on uptake and release of the neurotransmitter amines noradrenaline (NA), dopamine (DA) and 5-HT in brain slices. The (+)-isomer was more potent than the (-)-isomer at inhibiting MAO-A and MAO-B in vivo and at elevating brain levels of PEA and 5-HT in vivo. In contrast, (-)-TCP was more potent than (+)-TCP at inhibiting uptake of NA, DA and 5-HT. With regard to brain levels of the isomers, (-)-TCP attained a higher peak level than (+)-TCP, but was also cleared faster than the (+)-isomer.