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Updated: Jul 17, 2026

Facile Preparation of 4-Substituted Quinazoline Derivatives
Published on: February 15, 2016
beta-Carbolines and Tetrahydroisoquinolines: Detection and Function in Mammals
H Rommelspacher1, T May, R Susilo
1Department of Neuropsychopharmacology, Free University, Ulmenallee 30, D-1000 Berlin 19, Federal Republic of Germany.
Abstract:
beta-Carbolines occur in man and rat. The concentration in various tissues is about 100 to 1000 times lower than that of classical neurotransmitters. Administration of beta-carbolines in animals induces overlapping but not identical activity profiles. The molecular modes of action differ. For example, harman (1-methyl-beta-carboline) acts as an endogenous inhibitor of monoamine oxidase [E.C. 1.4.3.4.], subtype A, whereas norharman (beta-carboline) probably acts by stimulation of a specific beta-carboline receptor which is different from the benzodiazepine-GABA receptor complex. There is substantial evidence that tetrahydroisoquinolines occur under physiological conditions as well. Whether tetrahydropapaveroline serves as a precursor of morphinanes in mammals, as has been found in opium poppies, remains to be elucidated.
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