{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,27]],"date-time":"2026-09-27T11:40:35Z","timestamp":1790509235966,"version":"4.1.0"},"reference-count":0,"publisher":"Wiley","issue":"1","license":[{"start":{"date-parts":[[1977,12,1]],"date-time":"1977-12-01T00:00:00Z","timestamp":249782400000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["The Journal of Physiology"],"published-print":{"date-parts":[[1977,12]]},"abstract":"<jats:p>1. Intracellular pH (pH<jats:sub>i<\/jats:sub>) of surface fibres of the mouse soleus muscle was measured <jats:italic>in vitro<\/jats:italic> by recessed\u2010tip pH\u2010sensitive micro\u2010electrodes. pH<jats:sub>i<\/jats:sub> was displaced in an acid direction by removal of external (NH<jats:sub>4<\/jats:sub>)<jats:sub>2<\/jats:sub>SO<jats:sub>4<\/jats:sub> after a short exposure, and the mechanism of recovery from this acidification was investigated.<\/jats:p><jats:p>2. Removal of external K caused a very slow acidification (probably due to the decreasing Na gradient) but had no effect on the rate of pH<jats:sub>i<\/jats:sub> recovery following acidification. This indicates that K<jats:sup>+<\/jats:sup>\u2014H<jats:sup>+<\/jats:sup> exchange is not involved in the pH<jats:sub>i<\/jats:sub> regulating system.<\/jats:p><jats:p>3. Short applications of 10<jats:sup>\u22124<\/jats:sup> \n<jats:sc>M<\/jats:sc> ouabain had no obvious effect on pH<jats:sub>i<\/jats:sub> and did not alter the rate of pH<jats:sub>i<\/jats:sub> recovery following acidification. This suggests that there is no direct connexion between the regulation of pH<jats:sub>i<\/jats:sub> and the Na pump.<\/jats:p><jats:p>4. Reduction of external Ca from 10 to 1 m\n<jats:sc>M<\/jats:sc> caused a transient fall in pH<jats:sub>i<\/jats:sub>, but the rate of pH<jats:sub>i<\/jats:sub> recovery following acidification was unaffected. This suggests that Ca<jats:sup>2+<\/jats:sup>\u2014H<jats:sup>+<\/jats:sup> exchange is not involved in the pH<jats:sub>i<\/jats:sub> regulating system.<\/jats:p><jats:p>5. An 11% reduction in external Na caused a significant slowing of pH<jats:sub>i<\/jats:sub> recovery following acidification. 90% or complete removal of external Na almost stopped pH<jats:sub>i<\/jats:sub> recovery. This suggests that Na<jats:sup>+<\/jats:sup>\u2014H<jats:sup>+<\/jats:sup> exchange is involved in pH<jats:sub>i<\/jats:sub> regulation.<\/jats:p><jats:p>6. Amiloride (10<jats:sup>\u22124<\/jats:sup> \n<jats:sc>M<\/jats:sc>) reversibly reduced the rate of pH<jats:sub>i<\/jats:sub> recovery to much the same extent as removal of external Na. Its effect was not additive to that of removal of external Na.<\/jats:p><jats:p>7. Internal Na ion concentration ([Na<jats:sup>+<\/jats:sup>]<jats:sub>i<\/jats:sub>), measured using Na<jats:sup>+<\/jats:sup>\u2010sensitive micro\u2010electrodes, fell on application of (NH<jats:sub>4<\/jats:sub>)<jats:sub>2<\/jats:sub>SO<jats:sub>4<\/jats:sub> and increased on its removal. The increase transiently raised [Na<jats:sup>+<\/jats:sup>]<jats:sub>i<\/jats:sub> above the level recorded before (NH<jats:sub>4<\/jats:sub>)<jats:sub>2<\/jats:sub>SO<jats:sub>4<\/jats:sub> application. This overshoot of [Na<jats:sup>+<\/jats:sup>]<jats:sub>i<\/jats:sub> was almost completely inhibited by amiloride. This is consistent with the involvement of Na<jats:sup>+<\/jats:sup>\u2014H<jats:sup>+<\/jats:sup> exchange in the pH<jats:sub>i<\/jats:sub> regulating system.<\/jats:p><jats:p>8. Removal of external CO<jats:sub>2<\/jats:sub> or application of SITS (10<jats:sup>\u22124<\/jats:sup> \n<jats:sc>M<\/jats:sc>) caused some slowing of the rate of pH<jats:sub>i<\/jats:sub> recovery following acidification by removal of (NH<jats:sub>4<\/jats:sub>)<jats:sub>2<\/jats:sub>SO<jats:sub>4<\/jats:sub>. The effect of SITS was additive to that of Na\u2010free Ringer or amiloride. These results suggest that Cl<jats:sup>\u2212<\/jats:sup>\u2014HCO<jats:sub>3<\/jats:sub><jats:sup>\u2212<\/jats:sup> exchange is also involved in the pH<jats:sub>i<\/jats:sub> regulating system and that it is a separate mechanism. Under the conditions used, Cl<jats:sup>\u2212<\/jats:sup>\u2014HCO<jats:sub>3<\/jats:sub><jats:sup>\u2212<\/jats:sup> exchange formed about 20% of the pH<jats:sub>i<\/jats:sub> regulating system.<\/jats:p><jats:p>9. Decreasing the temperature from 37 to 28 \u00b0C not only caused an increase in pH<jats:sub>i<\/jats:sub>, but also considerably slowed the rate of pH<jats:sub>i<\/jats:sub> recovery following acidification. We have calculated a <jats:italic>Q<\/jats:italic><jats:sub>10<\/jats:sub> for Na<jats:sup>+<\/jats:sup>\u2014H<jats:sup>+<\/jats:sup> exchange of 1\u00b74 and for Cl<jats:sup>\u2212<\/jats:sup>\u2014HCO<jats:sub>3<\/jats:sub><jats:sup>\u2212<\/jats:sup> exchange, 6\u00b79.<\/jats:p><jats:p>10. We conclude that the pH<jats:sub>i<\/jats:sub> regulating system is comprised of two separate ionic exchange mechanisms. The major mechanism is Na<jats:sup>+<\/jats:sup>\u2014H<jats:sup>+<\/jats:sup> exchange, which is probably driven by the transmembrane Na gradient. The other mechanism is Cl<jats:sup>\u2212<\/jats:sup>\u2014HCO<jats:sub>3<\/jats:sub><jats:sup>\u2212<\/jats:sup> exchange, which probably requires metabolic energy.<\/jats:p>","DOI":"10.1113\/jphysiol.1977.sp012095","type":"journal-article","created":{"date-parts":[[2014,12,19]],"date-time":"2014-12-19T08:15:35Z","timestamp":1418976935000},"page":"295-316","source":"Crossref","is-referenced-by-count":268,"title":["An investigation of the ionic mechanism of intracellular pH regulation in mouse soleus muscle fibres"],"prefix":"10.1113","volume":"273","author":[{"given":"C. Claire","family":"Aickin","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"R. C.","family":"Thomas","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"311","published-online":{"date-parts":[[1977,12]]},"container-title":["The Journal of Physiology"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/api.wiley.com\/onlinelibrary\/tdm\/v1\/articles\/10.1113%2Fjphysiol.1977.sp012095","content-type":"unspecified","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/physoc.onlinelibrary.wiley.com\/doi\/pdf\/10.1113\/jphysiol.1977.sp012095","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2023,11,6]],"date-time":"2023-11-06T05:46:04Z","timestamp":1699249564000},"score":1,"resource":{"primary":{"URL":"https:\/\/physoc.onlinelibrary.wiley.com\/doi\/10.1113\/jphysiol.1977.sp012095"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1977,12]]},"references-count":0,"journal-issue":{"issue":"1","published-print":{"date-parts":[[1977,12]]}},"alternative-id":["10.1113\/jphysiol.1977.sp012095"],"URL":"https:\/\/doi.org\/10.1113\/jphysiol.1977.sp012095","archive":["Portico"],"relation":{},"ISSN":["0022-3751","1469-7793"],"issn-type":[{"value":"0022-3751","type":"print"},{"value":"1469-7793","type":"electronic"}],"subject":[],"published":{"date-parts":[[1977,12]]}}}