Histamine, 5-hydroxytryptamine, and bradykinin, tested over a wide range of concentrations, failed to increase microvascular permeability to plasma proteins according to several tests in mesentery, tongue, and web of the frog (R. temporaria). Ethyl urethane did increase permeability in these tissues by these tests. Compound 48 80, presumed to be a degranulator of tissue mast cells in frogs as in mammals, increased microvascular permeability in a pattern closely resembling that produced by mechanical injury. It is suggested that the mast cells of the frog contain some unknown substance which mediates the microvascular response to tissue injury.
ASJC Scopus subject areas
- Cardiology and Cardiovascular Medicine