原始 paper： http://ajpregu.physiology.org/cgi/content/full/291/5/R1499 節錄其中一段 Bioelectrical Measurements The intestinal flat sheets from discrete intestinal fragments were collected and prepared as described. Epithelia were lightly stretched to minimize the unstirred boundary layer, pinned over the circular aperture (1 cm2) of the chamber with the perimeter area lightly greased to minimize edge damage, and mounted in a recirculation vertical Ussing chamber (4-ml half-chamber volume). Measurement of bioelectrical variables was performed only in symmetric conditions ^^^^^^^^^ by using the basolateral saline composition described in Table 2 under cm2) was automatically calculated from voltage deflections after bipolar 200-ms pulses of 50 muA were injected every minute. Rt and short-circuit current ^^^^^^^^^^^^^^^^^^^^^ (Isc; muA/cm) were monitored by means of Ag-AgCl electrodes connected to the chambers by 3-mm bore agar bridges (3 M KCl in 3% agar). Clamping of epithelia to 0 mV and recording of variables ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ was performed using a microcomputer-controlled voltage-current Clamp Electronic with automatic correction for fluid resistance and electrode voltage asymmetry (KMSCI, Aachen, Germany).voltage clamp to 0 mV. Ep\ ithelial resistance Rt ( 這一段是在講要怎麼測鈣離子在海水硬骨魚 腸道細胞從 apical 到 basal lateral 的 infux 和 efflux 有幾點不太懂： 1.就實驗設計的部份來說，為什麼要分 symmetric 跟 asymmetric condition? aymmetric 指的是 "maintaining the basolateral saline constant and changing the composition of the apical saline" 2.為什麼要測 short-circuit current？代表什麼意義？ 3."Clamping of epithelia to 0 mV"，patch clamp 不是針對單一culture後的細胞 做的嗎？如果直接拿 fresh 的 tissue，也可以做喔？？how？ --

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