Table 3.
Drug-induced responses (fold induction) | ||||
---|---|---|---|---|
GPCR | Response | Agonist | EGF | Agonist+EGF |
D1R | cAMP level | 12.8±0.8* | 1.3±0.4 | 13.7±1.5* |
IP level | 1.0±0.2 | 1.2±0.2 | 1.3±0.2 | |
ORL1R | cAMP level | 0.8±0.2 | 1.1±0.3 | 1.4±0.6 |
IP level | 1.0±0.2 | 1.2±0.1 | 1.3±0.2 | |
GRPR | cAMP level | 1.1±0.4 | 1.1±0.3 | 1.2±0.2 |
IP level | 9.7±0.5* | 1.2±0.1 | 10.1±0.6* |
Cos-7 cells were transfected with the cDNAs encoding Gs-coupled D1R, Gi-coupled ORL1R or Gq-coupled GRPR, and then labeled with [3H]adenine for cAMP assay, or [3 H]myo-inositol for IP assay. The cAMP and IP formation, which reflects the activity of adenylyl cyclases and phospholipase C, respectively, was determined at 30 min after individual or co-stimulation with specific agonists (10 μM Dopamine for D1R, 100 nM OFQ for ORL1R, 100 nM bombesin for GRPR and 100 ng ml−1 EGF for EGFR). Data represent the mean±s.e. from three separate experiments, with the corresponding basal activities defined as one-fold of induction.
Agonist treatment significantly increased the cAMP or IP formation over basal levels (Bonferroni's corrected t-test, one-way ANOVA, P<0.05).