Effect of histamine releasers and of anti-inflammatory drugs on the egg-white edema of rat's hind paws in relation to skin histamine

1. A method was described for a fairly accurate judgement of the effect of drugs inhibiting the edema in hind paws of a rat caused by local injection of egg white. 2. The degree of inhibition of egg-white edema by single doses of sinomenine, compound 48/80, or dextran was in parallel with histamine reduction in skin and other tissues of the paws (and the skin of abdomen), although prevention of the edema by prolonged treatment with sinomenine was incomplete even when the releasable histamine of the skin was practically exhausted. 3. Sodium salicylate, aminopyrine, butazolidine sodium, cortisone, and guaiazulene were capable of inhibiting egg-white edema without modifying the content of skin histamine. These drugs and a small dose of phenergan potentiated the inhibition by dextran of egg-white edema and inhibited the release of histamine by dextran. These actions lasted for over 24 hours with the exception of guaiazulene. 4. Irgapyrin and a large dose of phenergan, which possess actions of histamine release and of histamine release inhibition and also antihistaminic action, caused a slight reduction of skin histamine and a comparatively marked inhibition of the edema. 5. In adrenalectomized or hypophysectomized rats, the edema-inhibiting effect of salicylate and aminopyrine decreased but that of cortisone increased. The effect of guaiazulene remained unchanged. 6. The observations that inhibition of egg-white edema is caused by (a) histamine releasers, (b) histamine-release inhibitor, and (c) drugs exerting both histamine release and inhibition of the release were discussed with the consideration to a relationship between egg-white edema and skin histamine.