Figure 2.

Dopamine stimulated dissociation of [³⁵S]GTPγS from CHO cell membranes expressing D₂ dopamine receptors, effects of raclopride. [³⁵S]GTPγS dissociation assays were performed as described in the Materials and methods section. Membranes were incubated with [³⁵S]GTPγS (0.1 nM) in the presence of dopamine (10 μM) for 60 min and [³⁵S]GTPγS dissociation was initiated by addition of 10 μM GTPγS. Parallel [³⁵S]GTPγS dissociation assays were performed in the absence and presence of raclopride (100 μM), added at the same time as the GTPγS. Basal [³⁵S]GTPγS dissociation has been subtracted from the data shown. Agonist-stimulated dissociation data were fitted best by a model of a single exponential decay. Data represented in this graph are from a single experiment replicated three times.