HISTAMINE AND 5-HYDROXYTRYPTAMINE IN THE BLOOD OF INFANTS AND CHILDREN

Abstract

The amount of histamine in the blood is closely related to the number of circulating basophils at birth and throughout childhood, and there is little or no histamine in the plasma. Observations on children with eosinophilia and with acute rheumatism indicate that both basophils and eosinophils contain histamine. There is very little 5-hydroxytryptamine in the blood at birth but the amount increases at about the age of 4 months to levels comparable with those in adults. The increase is due to an increase in the amount of 5-hydroxytryptamine per platelet, and the low levels at birth are probably due to immaturity of the capacity of platelets to take up 5-hydroxytryptamine. An inverse relationship was found between the amounts of histamine and 5-hydroxytryptamine in the blood of healthy children.