The continuous bioassay of the release and disappearance of histamine in the circulation.
1. The blood-bathed organ technique was used for the continuous assay of histamine in circulating blood.2. Longitudinal strips of cat or kitten terminal ileum detect concentrations of histamine of 2-5 ng/ml; these are below the threshold at which hypotension is induced in dogs.3. The cat or kitten terminal ileum also contract to bradykinin. However, the simultaneous use of a cat jejunum strip, which is selectively sensitive to bradykinin, will distinguish between histamine and bradykinin.4. The utility of the method for detecting and quantitating circulating histamine was exemplified by measuring: (a) its half-life in the circulation, (b) its disappearance during a passage through the vascular beds of lungs, liver and lower limbs, and (c) its release into the circulation by compound 48/80.
D000818:Animals; D001681:Biological Assay; D001920:Bradykinin / Q000494:pharmacology; D002415:Cats; D004285:Dogs; D005260:Female; D006207:Half-Life; D006632:Histamine / Q000097:blood* / Q000378:metabolism; D007082:Ileum / Q000187:drug effects; D007583:Jejunum / Q000187:drug effects; D008099:Liver / Q000378:metabolism; D008102:Liver Circulation; D008168:Lung / Q000378:metabolism; D008297:Male; D008722:Methods; D010477:Perfusion; D011652:Pulmonary Circulation; D003189:p-Methoxy-N-methylphenethylamine / Q000494:pharmacology
D003189:p-Methoxy-N-methylphenethylamine; D006632:Histamine; D001920:Bradykinin