A comparison of 6,7-dihydroxytetrahydroisoquinoline, salsolinol and tetrahydropapaveroline as inhibitors of monoamine oxidase within the adrenergic nerve plexus of the isolated mouse atrium.

Three dopamine-derived tetrahydroisoquinolines (TIQs) were tested for their ability to inhibit monoamine oxidase (MAO) within the adrenergic plexus of atria from reserpinized mice. Inhibition of MAO was shown by improved accumulation of 3H-norepinephrine with a concomitant decrease in 3H-deaminated catechols. Salsolinol was less potent than 6,7-dihydroxy-TIQ as a MAO inhibitor. Tetrahydropapaveroline did not appear to inhibit MAO in this system.