Mechanisms of Chloride and Bicarbonate Secretion Across Rat Proximal Colon Evoked by a CO Donor

Abstract The aim of the present study was to investigate whether carbon monoxide induces changes in ion transport across rat proximal colon. In Ussing chamber experiments, tricarbonyldichlororuthenium(II) dimer (RuCO), a CO-donor, evoked a concentration-dependent increase in short-circuit current (Isc). Anion substitution experiments suggest that a secretion of Cl− and HCO3 − underlie the RuCO-induced current. Partial inhibition by the neurotoxin tetrodotoxin suggests the involvement of secretomotor neurons in this response. Consequently, endogeneous carbon monoxide might be a physiological modulator of colonic…