Josefsson J O, Hansson S E
Acta Physiol Scand. 1976 Apr;96(4):456-70. doi: 10.1111/j.1748-1716.1976.tb10215.x.
Ultraviolet (UV) irradiation (4 000-10 000 erg X mm(-2) decreased membrane potential and input resistance of Amoeba proteus and induced formation of pinocytotic channels. Submaximal pinocytosis induced by UV light was additive to pinocytosis induced by K+ or Na+ and stimulated in the presence of EGTA. It was not inhibited by the presence of La+++ or by pretreatment with dibucaine. In these respects and with respect to optimum pH and pCa, UV induced pinocytosis. Accumulation of K+ in the amoeba membrane after a dose of radiation may explain the similarity between pinocytosis induced by UV light and potassium salts. Ca++ present during the period of irradiation inhibited the effect of UV light. Instead Ca++ applied after irradiation (1-20 mM) increased channel formation. This effect was stimulated the presence of local anesthetic drugs. It is suggested that high doses of UV light may induce channel formation by releasing Ca++ from the cell membrane into the cell (UV induced pinocytosis). Ca++ may be released at the moment of absorption of UV light in the membrane as well as during the period of depolarization which follows irradiation. Low doses of UV light may permit extracellular Ca++ to enter the cell and stimulate channel formation (calcium induced pinocytosis). Dithiotreitol (1 mM) applied after irradiation depressed both UV and calcium induced pinocytosis so these may be the result of the same structural change which involves the formation of disulphide bonds in the membrane.
紫外线（UV）照射（4000 - 10000尔格×毫米⁻²）降低了变形虫的膜电位和输入电阻，并诱导了胞饮通道的形成。紫外线诱导的亚最大胞饮作用与钾离子或钠离子诱导的胞饮作用具有叠加性，且在乙二醇双四乙酸（EGTA）存在的情况下受到刺激。它不受镧离子（La³⁺）的存在或丁卡因预处理的抑制。在最佳pH值和钙离子浓度方面，紫外线诱导了胞饮作用。一定剂量辐射后，变形虫膜中钾离子的积累可能解释了紫外线诱导的胞饮作用与钾盐诱导的胞饮作用之间的相似性。照射期间存在的钙离子抑制了紫外线的作用。相反，照射后施加的钙离子（1 - 20毫摩尔）增加了通道的形成。局部麻醉药物的存在刺激了这种作用。有人认为，高剂量的紫外线可能通过将细胞膜中的钙离子释放到细胞内来诱导通道形成（紫外线诱导的胞饮作用）。钙离子可能在细胞膜吸收紫外线的瞬间以及照射后随之而来的去极化期间释放。低剂量的紫外线可能允许细胞外钙离子进入细胞并刺激通道形成（钙诱导的胞饮作用）。照射后施加的二硫苏糖醇（1毫摩尔）抑制了紫外线和钙诱导的胞饮作用，因此这些可能是涉及膜中二硫键形成的相同结构变化的结果。
