Octopamine → Dopamine

Participants

Reaction Steps

Tyramine (TA), octopamine (OA) and norepinephrine (NE), naturally occurring monoamines that have a similar structure to DA, were tested together with DA for their ability to inhibit 3H-DA uptake. The concentration range of an unlabeled competitive inhibitor was selected according to the expected IC50 value. The IC50 values obtained were 0.39±0.11 μM for TA, 1.92±0.28 μM for OA, 4.10±1.02 μM for DA and 22.04±2.94 μM for NE. The apparent Ki values (calculation based on Cheng et al., (1973) Biochem Pharmacol 22:3099) were 0.35±0.10 μM for TA, 1.74±0.25 μM for OA, 3.72±0.92 μM for DA and 20.04±2.67 μM for NE. The rank order of apparent Ki on OA/TAT for potential substrates was: TA<OA<DA<NE.

Provenance & Evidence