Effect of cyclooxygenase inhibition, deafferentation, or atropine on l-Glu/IMP-induced HCO3− secretion in rat duodenum. Rats were pretreated with vehicle (Veh-t), indomethacin (Indo-t), or capsaicin (Cap-t) or intravenously injected with vehicle or atropine (1 mg/kg). Indo-t partially inhibited l-Glu/IMP-induced HCO3− secretion, whereas Cap-t (B) or intravenous atropine (C) had no effect. Each data point represents mean ± S.E.M. (n = 6 rats). *, p < 0.05 versus pH 7.0 Krebs group. †, p < 0.05 versus Veh-t + l-Glu + IMP group.