Abstrakt: |
Extracts of the stinging hairs of the Gympie bush (Laportea moroides) have been found to contain 0.01-0.025 µg. acetylcholine-like activity, 0.025-0.05 µg. histamine-like, and 0.001 µg. 5-hydroxytryptamine-like activity per hair. Intradermal injection of dialysed extract, free of acetylcholine, histamine and 5-hydroxytryptamine, causes the characteristic intense pain, flare, piloerection and local sweating of a Laportea sting. Specific blockade of the action of acetylcholine, histamine and 5-hydroxytryptamine did not prevent the production of nettle pain. A stable, non-dialysable substance, resistant to heat, neutral in reaction, unattacked by proteolytic enzymes appears to be the essential pain-producing material. It also induces sweating, piloerection and arteriolar dilatation. [ABSTRACT FROM AUTHOR] |