Differences in the mode of exudative reaction between early phase and late phase of carrageenin-induced inflammation in rats

Differences in the mode of vascular permeability change induced by some stimulants such as chemical mediators between the early phase and the late phase of the carrageenin-induced granulomatous inflammation were investigated with the aid of ¹³¹I-human serum albumin as an indicator for the measurement of vascular permeability. In the early pregranulomatous phase of the inflammation, histamine injection into the inflammation locus markedly elevated local vascular permeability, while prostaglandins E₁ and E₂ showed no effect. On the other hand, in the late phase of the inflammation, where permanent granuloma tissue had been formed, prostaglandins E₁ and E₂ significantly enhanced the local vascular permeability, while histamine was inert.