Fig. 3
Concentration-dependent effects of selective EP1, EP2, EP3, and EP4 receptor agonists on GC frequency and amplitude. In the presence of TTX and piroxicam, vehicle control (DMSO) or each EP receptor agonist, including ONO-DI-004 (a; EP1), ONO-AE1-259 (b; EP2), ONO-AE-248 (c; EP3) and ONO-AE1-329 (d; EP4), was added to the bathing solution (10−11, 10−10, 10−8, 10−7, or 3 × 10−6 mol L−1) at ~ 30-min intervals, and these traces are shown. Concentration–response curves of the normalized mean frequencies and amplitudes (see Methods and Results) are shown in e and f with data on PGE2. Data are expressed as means ± SE (for frequency, PGE2, n = 4; the other agonists, n = 5)