抄録
Since the fluid mosaic model for the biological membrane has been proposed by Singer and Nicolson (21), many investigators have reported that the membrane fluidity is closely related to the various metabolic functions of the cell. The present investigation was performed to examine that a biscoclaurin alkaloid, cepharanthin which showed protective effects from the snake venom action might modify the fluidity to various cell membranes modulated by various agents. The obtained results were as follows.
1. Cepharanthin inhibits K+ release from red blood cells, Ehrlich ascites tumor cells, AH-130 ascites hepatoma cells and liposome when these were treated with snake venom, phospholipase A, lysolecithin and lead acetate. But cepharanthin does not inhibit K+ release induced by ionophores, Triton X-100 and HVJ.
2. Cepharanthin inhibits the release of histamine from rat peritoneal mast cells induced by various releasers.
3. The alkaloid inhibits cap formation of rat monocytes and Ehrlich ascites tumor cells.
4. Fluorescence polarization analyses and spin-label studies indicated that cepharanthin decreased fluidity of various biological membranes.
5. From these results it is concluded that cepharanthin decreases membrane fluidity and acts as a potent membrane stabilizing agent.
