Differential effects of harmaline and ouabain on intestinal sodium, phenylalanine and ?-methyl-glucoside transport

Publisher Website
Google Scholar
Abstract
Harmaline inhibits both the Na+-K+-ATPase activity and the uptake of l-phenylalanine in guinea-pig intestinal mucosa. The latter effect is not a direct consequence of the former, since higher concentrations are needed to inhibit the enzyme than the influx into the mucosa. Furthermore the uptake is still sensitive to harmaline when the Na+-K+-ATPase has been fully inhibited by ouabain. Harmaline can inhibit l-phenylalanine influx at a concentration at which it does not affect intracellular ion concentrations. Ouabain, however, inhibits the uptake of l-phenylalanine only after a 30 min preincubation period, when the intracellular sodium concentration reached the extracellular level. Harmaline also interferes with the influx of β-methyl-d-glucoside in the mucosa of the dog colon. Addition of harmaline at the mucosal face of the tissue suppresses all net transport of sodium and chloride ions and l-phenylalanine across the mucosa. Thus the same mode of action appears to apply in both the guinea-pig ileum and the dog colon.

This publication has 20 references indexed in Scilit: