On the mechanism of suppressive action of some drugs influencing calcium ions on the histamine-induced contraction of guinea-pig ileum.

The effects of procaine, verapamil, EDTA, pyridoxine and disodium cromoglycate (DSCG) on histamine-induced contractions of isolated guinea-pig ileum have been compared. Procaine, verapamil, EDTA and DSCG exerted the protective action on the ileum against histamine either when the drugs were present in the organ bath or after they were washed out. This effect was dose- and time-dependent and reversible. On the other hand, the protective effect of pyridoxine against histamine-induced contraction of ileum disappeared quickly after removing of drug from the bath. It is suggested that all tested agents influence calcium utilization by muscle cells.