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THE EFFECT OF THE INJECTION OF SERUM ON THE HEART AND VESSELS OF THE CAT
Author(s) -
Ponder Eric
Publication year - 1927
Publication title -
quarterly journal of experimental physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.925
H-Index - 101
eISSN - 1469-445X
pISSN - 0370-2901
DOI - 10.1113/expphysiol.1927.sp000428
Subject(s) - blood pressure , vasomotor , medicine , anesthesia , free nerve ending , chloralose , endocrinology , chemistry
1. The intravenous injection of small quantities of serum produces in the cat a transient fall of blood‐pressure and a transient slowing and diminution of the amplitude of the heart‐beat. This is due to an effect of the serum on the pulmonary nerve‐endings, and a resulting effect on the cardiac and vasomotor centres. Brodie's results are thus confirmed. 2. This typical effect occurs only in the urethaned or etherised cat. In the cat under chloralose or chloral the heart effect is absent, but the effect on the vasomotor centre persists. 3. The effects are not produced by all sera, but by only about 80 per cent. of the number tested. Of these about 50 per cent. produced marked effects. The serum of the cat, rabbit, ox, horse, and of man are equally effective in doses of about 3 c.c. 4. One injection rapidly sets up a state of immunity to subsequent injections, the site of the immunity being the pulmonary nerve‐endings. The active substance may be shown to remain in the circulating blood for about five minutes, but no longer. The state of immunity lasts at least thirty minutes, often several hours; the length of its duration depends on the amount of serum injected. 5. In animals in which this immunity is established, or in animals with both vagi cut, the injection of the serum produces a slight fall of pressure without any accompanying effect on the heart, and due to a direct action on the peripheral vessels. This effect is always obtained with ether or urethane anæsthesia. In cats under chloralose anæsthesia the fall of pressure is occasionally replaced by a marked rise; more frequently by no effect at all. In pithed cats, in which the effect of the serum on the medullary centres is necessarily abolished, the serum may produce either a fall of pressure or, more rarely, a rise. These effects are not confined to the cat, but occur in the dog, rabbit, and rat. 6. The statement that the substance which has its action on the medullary centres is a protein of the albumin class, formed during clotting of the blood in the presence of red cells, is confirmed. The effects on the peripheral vessels are, however, due to another substance which is soluble in boiling alcohol, and which is insoluble in ether or acetone. This latter substance is probably formed after the shedding of the blood. This research was carried out with the aid of a grant from the Moray Fund of the University of Edinburgh.