The action of heavy metals on the isolated intestine

Abstract

In experiments with zinc which was used in the form of the malate and carried out on isolated segments of the intestines of cats and rabbits by the method of Magnus it was found that even low concentrations may produce depression of muscular activity. A solution N/20,000 zinc malate, proved to be quite active in some experiments. N/10,000 and N/5,000 zinc malate produced, after a brief preliminary stimulation, considerable decrease and sometimes irregularity of the force of rhythmic contractions. Occasionally decrease of frequency and tonus were also observed.

When the segments of the intestine were suspended in pure Locke solution again, some improvement occurred, although it had been acted upon by zinc 45-70 minutes. In experiments with concentrations of N/1,000 and N/500 and sometimes even with N/2,000 permanent injury to the tissues may be caused by the metal as no recovery could be observed when pure Locke solution was substituted for one containing zinc.

The action of nickel employed in the form of the acetate was also tested. Dilute solutions, N/10,000 and N/5,000 produced temporary depression followed by recovery and sometimes stimulation while the intestine was still in the solution of the salt. Complete abolition of rhythmic contractions and decrease of tonus were observed when much higher concentrations were used, but the effect was not permanent in these experiments as recovery in pure Locke solution took place after the intestine had been suspended in N/500 nickel acetate for twelve minutes. The reaction to pilocarpine and of barium was studied in experiments with both of the metals. The evidence obtained points to injury to nerve endings as well as of the muscle fiber, but the latter was in some experiments much more resistant.