Beta-carbolines and tetrahydroisoquinolines: detection and function in mammals.
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.
Rommelspacher
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H
Department of Neuropsychopharmacology, Free University, Berlin Federal Republic of Germany.
May
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T
Susilo
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D000818:Animals; D002243:Carbolines / Q000032:analysis; D006801:Humans; D007546:Isoquinolines / Q000032:analysis; D008322:Mammals
D002243:Carbolines; D007546:Isoquinolines