The toxicity of caffein: an experimental study on different species of animals

Abstract

About the same time Amory * (1868) published the results of his Studies on the toxicity of caffein in cats, dogs, rabbits, and pigeons. In all cases very large doses were introduced directly into the stomach by means of a temporary gastric fistula. Ten grains given in meat to a dog caused restlessness, but no other symptoms. Doses of 30 grains and above were invariably fatal. Seventy-three grains given to a cat caused death within 20 minutes. From observations on frogs, guinea pigs, rabbits, and on one dog, Leven^^(1868) concluded that caffein which he gave in the form of the citrate in doses of 10 mg to frogs, from 150 to 200 mg to guinea pigs, and three to four times the latter amount to rabbits, stimulates the central nervous system and the voluntary, cardiac, and smooth muscles. He found that 0.9 gram caffein was fatal for a rabbit when injected subcutaneously, while 1 gram of the citrate was not toxic for a dog of medium size. Caffein applied directly to muscle fiber causes tetanus and destroys muscular contractility, while a nerve fiber similarly treated loses its irritability. According to Johansen ** (1869), caffein acts directly on the muscular fiber. After the subcutaneous injection of 0.02 gram of caft'ein into frogs, he observed contraction of the muscles at the site of injection, then contraction of the anterior extremities, and finally the posterior extremities become rigid and extended. Johansen obsei-ved muscular rigidity after caffein, even after curara was injected, or after ligating the vessels, or cutting the nerves which supply the muscles. He also observed that large doses of caffein diminish muscular irritability. When cardiac muscle was poisoned with caffein, microscopical examination showed that the striations disappeared. Johansen also states that reflexes disappear after caffein poisoning. He never observed tetanus in frogs, but reported tonic and clonic convulsions a.s (Doses of 147 to 107 inK of cafloln per kilo were employod in these experiments.] Rabbit 3S2. Bclgicin hare, female. Weight, 1,070 grains. Diet, oats. March 25: 8.5 cc 2 per cent caffein (158 mg per kilo) injected subculaneously at 2.15 p. m.; 4 p. in., reflexes increased; 5.45 p. m., increases of reflexes still more marked. March 2(;: Rabbit looked normal; no symptom.s observed. Rabbit.1^1. Belgian hare, female. Weight, 1,170 grams. Diet, oaLs. March 25: 2.15 p. m., 9 cc 2 per rout caffein (153 mg per kilo) injected subcutaneously; 4 p. m., reflexes increa.sed; 5.45 p. ni., condition the same. March 2(j: Rabbit looks normal; no symptoms observed. Rabbit 3JS. Belgian hare, female. Weight, 1,300 grams. Diet, oats. March 25: 9 cc 2 percent caffein injected subcutaneously (1-50 mg per kilo); 4 p. m., reflexes increased; 5.45 p. m., reflexes increased but not markedly. March 26: No symptoms; rabbit looks normal. Rabbit 322. White female. Weight, 1,065 grams. Diet, oats. March 17: 8 cc 2 per cent caffein (150 mg per kilo) injected subculaneoiisly at 11.55 a. m.; 12. .55 p. m., reflexes increased, but no tetanus nor any oilier...

The absorption and excretion of zinc

“…From the small number of papers which have been published on the subject, it is probable -that the response of animals to Zn injections will be found to be similar to that of human beings. Salant, Rieger & Treuthardt [1918] injected Zn into rabbits and cats in quantities relatively greater than those used in the present experiments, and subsequently found very little in the urines, but quantities up to half the amounts injected in the intestinal tracts. It is not clear from their paper, however, whether due allowance was made for the Zn in the animals' food, and particularly in that of the rabbits.…”

Studies on the Toxicity of Alkyl Tin Compounds

“…In recent years the toxicity of tin has aroused little interest, but in the latter part of the last century and the first decade of this, considerable attention was paid to the possible contamination of food preserved in cans (White, 1881;Ungar and Bodlander, 1886; Lehmann, 1902;Eckhardt, 1909;Schryver, 1909). It was concluded that there was no serious risk; since then there have only been occasional studies on the toxicity of tin compounds (Salant, Rieger, and Trenthardt, 1914;Handovsky, 1925;Schwartzer and Clarke, 1927;Seifter and Rambousek, 1943). A suggestion that the fungicidal properties of certain organic tin compounds might have industrial application (Van der Kerk and Luijten, 1954) coupled with their use as " plasticizers " has rekindled interest in this subject.…”