Cationophore properties of the new polyether antibiotic Salinomycin investigated in distal rabbit colon in vivo and in vitro.
The distal rabbit colon was used as a model to investigate the influence of the cationophore Salinomycin in vivo with a single-pass perfusion, and in vitro with a modified Ussing chamber technique. For in vivo experiments with labelled 14C-PEG as a volume marker in the perfusate, a dose of 10E-4 mol/l Salinomycin was used. Net water (53 microliters/h/cm), net chloride (3 mumol/h/cm) and net sodium (3.6 mumol/h/cm) absorption was not significantly influenced, but net potassium secretion (-3 mumol/h/cm) was decreased to zero and transepithelial potential (PD) reduced from -45 mV to -33 mV. 10E-4 mol/l Salinomycin, applied in vitro on the muscosal side, decreased PD in 80 min and 10E-3 mol/l in 30 min from 18 mV to zero. Both concentrations decreased the short-circuit current (Isc = 77 microA/cm2) in 60 min, respectively 30 min to 40 microA/cm2. After 60 min mucosal 10E-4 mol/l Salinomycin the Isc increased, resulting from a transepithelial conductance (Gt) increase from 3 to 40 mS/cm2. A dose-related effect was present on PD, Isc and Gt at concentrations between 10E-7 and 10E-6 mol/l. The unidirectional 22Na fluxes were increased to 20 times the control values and net Na transport disappeared. We conclude that Salinomycin when applied in usual doses (10E-4 mol/l) as a coccidiostatic feed additive, profoundly affects colonic electrolyte transport.
D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001834:Body Water / Q000378:metabolism; D002712:Chlorides / Q000378:metabolism; D003106:Colon / Q000187:drug effects*; D007408:Intestinal Absorption / Q000187:drug effects; D008297:Male; D010477:Perfusion; D011188:Potassium / Q000378:metabolism; D011714:Pyrans / Q000494:pharmacology; D011817:Rabbits; D012964:Sodium / Q000378:metabolism; D000095662:Polyether Polyketides
D000900:Anti-Bacterial Agents; D002712:Chlorides; D011188:Potassium; D011714:Pyrans; D012964:Sodium; C010327:salinomycin; D000095662:Polyether Polyketides