히스타민으로 유발시킨 피부염증 부위의 RISA 클리어런스 및 수분 이동

Abstract

Movements of RISA across capillary membrane after intradermal injection of histamine were studied in anesthetized rabbits. Intravenous injection of 2 ml saline solution containing 30-100 μC of RISA and 1 % Evans blue dye was given to the animal. The dye served as a guide in delineating the area of inflammatory tissues. In order to ensure uniform distribution of the injected materials, 10 minutes were allowed to elapse before saline and logarithmic doses of histamine dihydrochloride in a volume of 0.05 ml were injected intradermally. A total of 7 sites were injected on the abdominal skin of each animal. Ten minutes after the intradermal injections, animal was killed , the skin sites were excised and blood samples were taken by cardiac punctures. From the tissue and blood samples , radioactivities of RISA, concentration of sodium and tissue water content were analyzed. Calculations were made on contents of tissue water, Na space as a size of extracellular fluid space, size of intracellular fluid and local clearances of RISA. The following results were obtained. 1. Tissue water content of skin increased as the injected dose of histamine increased. The dose-response -curve showed a S-shaped curve. Tissue water content at the control skin site was 67.8±2. 3%. At 10- 3μg histamine injected skin site the tissue water content was only slightly greater than that of the control. As the injected dose of histamine increased up to a dose of 101μg， skin tissue water content increased steeply_ Thereafter skin tissue water content maintained a maximum plateau value of 76.0±2. 9% at a dose of 102 μg histamine. 2. Histamine dose-response curves of extracellular and intracellular fluid were similar to the tissue water change showing a typical sigmoid curve. The size of extracellular fluid volume determined as Na-space shoo wed 41.5±1.0% in the control site and increased to the maximum plateau value of 44.8±1. 9 % at the dose of 102μ g histamine. The size of intracellular fluid volume determined by difference between total tissue water and Na-space was averaged of 26.3 %in the control site and increased to the maximum plateau value of 31. 2 % in the site injected 102μ g of hista· mme. 3. The RISA clearance was averaged O. 036±0. 005 cc/gm at the control site which value represents the plasma volume of normal skin. Clearances in the inflammatory sites induced by graded dose of histamine increased with the same fashion as in the change in tissue water. Thus, a modest increase at a dose of 10-3 μg histamine, steep increase at the doses of 10-2-101 μ g， thereafter a maximum plateau value of O. 206± 0.032 cc/gm were observed. The actual extravasated or transudated plasma volumes can be calculated by {}btaining the differences of clearance values of control .site and inflammatory sites. The maximum plasma "Volume extravasated was calculated as O. 17cc/gm which is about 5. 7 times of the normal plasma volume. 4. From the point of view that dose-response curves of total tissue water, extracellular fluid , intracellular fluid and RISA clearance showed typical sigmoid cur· ves, the inflammatory reactions induced by graded doses of histamine were divided into 3 steps according to their intensity and mechanism of changes. Each step of changes was discussed.