PHYSIOLOGY AND BIOCHEMISTRY OF SHOCK 401 



fatal guinea pig anaphylaxis to account for the death of the animal. 



a. Symptoms in Guinea Pigs, After intravenous injection into a 

 sensitized animal, there is a prodromal period of a few minutes during 

 which the animal usually sneezes, scratches its nose, becomes restless, 

 discharges urine and feces, becomes weaker and rolls over on its side. 

 Acute respiratory difficulty then develops, and death from asphyxia 

 may follow in less than 10 minutes. Due to a swiftly developing 

 stenosis of the bronchioles there is inadequate air exchange with a 

 resulting asphyxia despite the violent respiratory efforts. This 

 bronchiole reaction is due to a direct action on the muscular walls of the 

 bronchi and not due to a central or reflex nervous reaction. An initial 

 moderate rise in systemic blood pressure followed by a gradual fall, is 

 similar to that occurring in asphyxia from any cause. It is considered 

 that the anaphylactic reaction is primarily pulmonary and the circula- 

 tory effects are secondary in importance (Dragstedt, 1941). The 

 anaphylactic symptoms described here have been found to be associated 

 with the liberation of histamine from the lungs of the guinea pig. 

 An increase in the blood histamine of anaphylactic animals up to 

 13 times the normal values has been found (Code, 1939; 1944). 



b. Symptoms in the Dog. The anaphylactic reaction is associated 

 with dyspnea, vomiting, salivation, general weakness, diarrhea and a 

 marked progressive fall in blood pressure due to peripheral vasomotor 

 paralysis. With the decrease in arterial pressure there is a decrease in 

 the blood volume of the kidney, intestine and spleen, while there is 

 a large accumulation of blood in the liver. The vascular reaction in 

 anaphylactic dogs has been accounted for by the amount of histamine 

 released from the liver (Dragstedt and Mead, 1936a, 1936b); and the 

 severity of the shock in dogs is accompanied and paralleled by a reduc- 

 tion in liver histamine (Ojers, Holmes and Dragstedt, 1941). 



The loss of coagulability of dog's blood during anaphylaxis has 

 been found to be due to the simultaneous liberation of heparin with 

 the histamine from the injured liver (Jacques and Waters, 1941). 



c. Symptoms in the Rabbit. The anaphylactic shock produced by 

 intravenous reinjection of antigen causes quickening of respiration, 

 sinking of the animal upon its abdomen, expelling of feces and urine, 

 fleeting hyperemia followed by anemia of the ears; the heart beat be- 

 comes feeble, agonal convulsions may develop and the animal may 

 die within a few minutes. 



