Influence of cholecystokinin on the synaptosomal dopamine uptake in the nucleus accumbens of rats.
The influence of the sulfated cholecystokinin octapeptide (CCK-8S) on the synaptosomal high-affinity [(3)H]dopamine (DA) uptake was investigated in the medial and lateral part of nucleus accumbens in rats. CCK-8S induced a concentration-dependent biphasic inhibition of [(3)H]-DA uptake in both subregions. After preincubation of CCK-8S with the synaptosomes the inhibitory effect was completely abolished. Kinetic analysis of the uptake influence suggests an uncompetitive inhibition by CCK-8S; this means that CCK-8S attacks only the DA-uptake carrier complex by inhibitory manner. The possible regulatory relevance of this mechanism is discussed.
Hetey
L
L
Institute of Medical Chemistry, University Medical School, 6701 Szeged POB 531, Hungary.
Döring
E
E
Penke
B
B