| The termination of chemical neurotransmission involves the movement of neurotransmitters across cell membranes by a transport protein selective for the neurotransmitter. To assess the functional properties of the dopaminergic transport system in rat striata, the rate of the inward transport of dopamine (3,4-dihydroxyphenethylamine) was measured, under varying conditions, using rotating disk electrode voltammetry. Initial experiments were performed in order to gain some fundamental information about the chemistry of dopamine, as a substrate, as well as the transporter. It was found that the catechol moiety of dopamine is needed for substrate recognition at the transporter, the ethylamine side chain is required for translocation, and sulfhydryl groups and external glycosylation of the transporter are necessary for optimal transport. In addition, an experimental approach to resolve the rate of association of dopamine with the transporter (k;Other studies investigated the effects of cocaine and other less addictive inhibitors of the uptake process on the kinetic parameters k... |
