Table 2

Agonist potency for inhibition of isoproterenol-stimulated adenylate cyclase activity by D2S and serine mutant receptors

AgonistEC50
D2SS193AS194AS197A
nm
Dopamine3  (2–4)2000  (1000–3000)b N.R. 5  (1–20)
NPA0.04  (0.03–0.06)0.84  (0.36–2)2  (1–3)0.09  (0.01–0.7)
DHX23  (5–100)N.R. N.R. 34  (23–51)
Quinpirole3  (2–5)2  (2–3)47  (35–61)b 1  (0.4–2)
7-OH-DPAT0.2  (0.05–0.4)5  (4–6)2-a 0.4  (0.2–1)0.4  (0.1–1)

Inhibition of adenylate cyclase activity was determined as described in Table 1. EC50S values are expressed as the geometric mean followed by the limits defined by the asymmetrical standard error from at least three independent experiments.

    • N.R., no detectable response.

    • 2-a p < 0.05, b p < 0.01 compared with D2S (Dunnett’s post hoc repeated-measures analysis of variance).