不是來自於麻婆豆腐就是
https://imgur.com/ZoqLqzW
論文出處：
https://www.nature.com/articles/s41467-023-41637-4
Sensitivity to NH4Cl is conserved across species variants of OTOP1
We next asked if sensitivity to NH4Cl is conserved among different species
variants of OTOP channels, as might be expected given the broad range of
organisms that find the taste of NH4Cl aversive. When expressed in HEK-293
cells, human, chicken, and zebrafish OTOP1 channels all responded to NH4Cl
with large inward currents (Fig. 4a); in each case, the ammonium-induced
currents were inhibited by 1M Zn2+. For mouse OTOP1, we observed
potentiation of the response to NH4Cl following the removal of Zn2+, as
previously reported for mild acid-evoked responses36. Interestingly, we
observed variation in the magnitudes of the responses to NH4Cl among the
different species variants of OTOP1 (Fig. 4b). For example, relative to its
response to the acidic stimulus, chicken OTOP1 carried much larger inward
currents in response to NH4Cl. Meanwhile, zebrafish OTOP1 was less sensitive
to NH4Cl but responded well to the acid stimulus. Human OTOP1 was
intermediate, responding well to both the acid stimulus and NH4Cl but with
somewhat different kinetics than mouse OTOP1. Thus, in all species tested,
and likely all vertebrate species, OTOP1 could serve as a sensor for NH4Cl.
Differences in the sensitivity of the species variants of OTOP1 to NH4Cl and
acids may reflect a diversity in behavioral ecology.
研究人員之前發現，負責感知酸味的TRCs會表達一種名為otopterin1（Otop1）的基因，
這個基因會編碼一種蛋白質OTOP1，它可以形成質子通道，讓細胞能夠感知到低pH值和酸
味。
在這項新的研究中，研究人員想要了解酸味的TRCs和OTOP1對於感知氨氯（ammonium
chloride）的貢獻是什麼。他們將Otop1基因引入到實驗室培養的人類細胞中，並將一些
細胞暴露於酸或氨氯中。他們發現，氨氯能夠像酸一樣有效地激活OTOP1受體。進一步的
實驗在老鼠身上得到了證實，具有Otop1基因的老鼠會避開氨氯，而那些基因被敲除的老
鼠則不會。
氨和它的氣體態—氨氣，是氨基酸的分解產物，對人類和其他動物來說通常是有毒的。基
於這項發現，研究人員推測，感知氨氯的能力可能是為了幫助生物避免攝入有害物質而演
化出來的。
研究人員也觀察到了不同物種之間的差異。人類和老鼠的OTOP1通道會被氨氯強烈激活，
雞的OTOP1通道對氨氯更敏感，而斑馬魚則對氨氯的敏感度較低。他們認為，這些物種間
的差異反映了每個生物的生態位。例如，眾所周知，鳥類對酸味的敏感度較低，但它們需
要避免攝入存在於它們排泄物中的氨氯。