Binding sites for [3H]cocaine in mouse striatum and cerebral cortex have different dissociation kinetics.
[3H]Cocaine dissociates from its binding sites in the mouse cerebral cortex with a half-time of 25 s. The dissociation kinetics in the striatum is consonant with the presence of two populations of sites with dissociation half times of 2 s and 27 s, comprising 88% and 12%, respectively, of the total binding sites. On the basis of previous pharmacological characterization of [3H]cocaine binding, we propose that the slowly dissociating component represents the sites associated with 5-hydroxytryptamine (serotonin) uptake, and the rapidly dissociating component the 3,4-dihydroxyphenylethylamine (dopamine)-related sites. Evidence is presented that the extremely high dissociation rates do not preclude the measurement of [3H]cocaine binding by rapid filtration. The dissociation of [3H]cocaine from cerebrocortical membranes is slowed to a small but statistically significant extent by serotonin.
D000818:Animals; D001665:Binding Sites; D002540:Cerebral Cortex / Q000378:metabolism*; D003042:Cocaine / Q000378:metabolism*; D003342:Corpus Striatum / Q000378:metabolism*; D007700:Kinetics; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D012701:Serotonin / Q000378:metabolism
D012701:Serotonin; D003042:Cocaine