Kurihara K, Katsuragi Y, Matsuoka I, Kashiwayanagi M, Kumazawa T, Shoji T
Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan.
Physiol Behav. 1994 Dec;56(6):1125-32. doi: 10.1016/0031-9384(94)90356-5.
The receptor mechanism of bitter substances was discussed from the following points of views. (a) Both electrostatic and hydrophobic interactions of bitter substances with taste receptor membranes contribute to reception of bitter substances having a positive charge. (b) In the frog, the responses to bitter substances are easily adapted. The presence of Ca ion in the medium prolongs the responses. (c) Bitter substances elicit electrical responses in nongustatory cells such as neuroblastoma cells and olfactory cells, suggesting that bitter substances induce the response by nonreceptor-mediated mechanism. (d) There is also a possibility that receptors for some bitter substances are G-protein coupled. We cloned G-protein coupled receptors from bovine taste tissues. (e) A specific inhibitor of bitter taste has been desired in pharmaceutical and food sciences, but it has not been available. We found that a lipoprotein made of phosphatidic acid and beta-lactoglobulin selectively inhibits the responses to bitter substances in the frog and humans. Binding of the lipoprotein to the receptor sites for bitter substances leads to suppression of the response.
从以下几个方面讨论了苦味物质的受体机制。(a) 苦味物质与味觉受体膜的静电相互作用和疏水相互作用都有助于对带正电荷的苦味物质的感受。(b) 在青蛙中，对苦味物质的反应很容易适应。培养基中钙离子的存在会延长反应。(c) 苦味物质在神经母细胞瘤细胞和嗅觉细胞等非味觉细胞中引发电反应，这表明苦味物质通过非受体介导的机制诱导反应。(d) 某些苦味物质的受体也有可能是G蛋白偶联的。我们从牛的味觉组织中克隆了G蛋白偶联受体。(e) 在制药和食品科学领域，一直需要一种苦味的特异性抑制剂，但尚未获得。我们发现，由磷脂酸和β-乳球蛋白制成的脂蛋白能选择性地抑制青蛙和人类对苦味物质的反应。脂蛋白与苦味物质的受体位点结合会导致反应受到抑制。
