The effects of various pharmacological agents on the distribution of antihistamine activity of rat tissue extracts

Abstract

Extracts of rat tissues (ear and abdominal skin, heart, cerebrum, spleen, kidney, lung, liver, stomach, and jejunum) were tested for their ability to antagonize histamine on the guinea pig ileum preparation. Antihistamine activity varied considerably between tissues; it was found to be highest in the ear skin and lowest in the jejunum and stomach. After pretreatment with semicarbazide (plus a pyridoxine-free diet) or reserpine, or after adrenalectomy, the antihistamine activity was reduced in some tissues but was increased in others. The variation in the behavior of the different tissues with these treatments made it impossible to interpret the distribution of antihistamine activity in terms of known sites of amine formation. After treatment with compound 48/80, however, there was an apparent parallelism between loss of antihistamine activity and depletion of mast cell histamine.