Effect of lead salts and of the nitrites upon the movements of the intestines

Abstract

Riegel (1875) and J. Pal (Die Gefässkrisen, 1906) suggested the use of amylnitrite for the control of pain in lead colic and in the gastric crises of tabes dorsalis, believing that the fall of blood pressure sufficed to bring about diminution in these symptoms.

The present series of experiments was undertaken in order to determine whether the nitrites might not act by causing relaxation of a spastic condition of the intestinal walls. The experiments were carried out on rabbits whose intestinal movements were observed through a large window in the abdominal wall, which was closed from the outside air by inserting a crystallizing dish 10 cm. in diameter. The sides of the crystallizing dish were coated with thick beeswax and the window was held in place by fixing the abdominal walls around it with a purse string suture. The animals were lightly anæsthetized with ether.

Injection of 5 mg. lead acetate per kg. immediately caused the onset of intense peristaltic movements which seemed to be due to stimulation of the preganglionic synapse, since they were abolished by injection of nicotin or by painting nicotin upon the intestine, but were not affected by extirpation of the spinal cord and section of the vagi. As was suspected from the clinical results reported by Riegal and Pal, this peristalsis could be inhibited by inhalation of amylnitrite, by placing two drops of nitroglycerin upon the tongue or by the injection of 80-100 mg. per kg. sodium nitrite. The effects of the two former drugs were most marked, though the effects of the latter were more prolonged. Atropin, either locally or intravenously, also inhibited the peristalsis, as had been shown by Harnack.

The same effects were also obtained with the nitrites and with atropin when increased peristalsis was brought on by the local effect of heat, secured by placing warm water in the crystallizing dish window.