{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,9,23]],"date-time":"2025-09-23T14:49:17Z","timestamp":1758638957443},"reference-count":0,"publisher":"Wiley","issue":"1","license":[{"start":{"date-parts":[[1980,3,1]],"date-time":"1980-03-01T00:00:00Z","timestamp":320716800000},"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":[[1980,3]]},"abstract":"<jats:p>1. The intracellular Na activity (<jats:italic>a<\/jats:italic><jats:sub>Na<\/jats:sub><jats:sup>i<\/jats:sup>) of quiescent sheep heart Purkinje fibres has been measured using Na<jats:sup>+<\/jats:sup>\u2010sensitive glass micro\u2010electrodes. The effects of local anaesthetics (procaine and lidocaine) and tetrodotoxin (TTX) have been investigated.<\/jats:p><jats:p>2. Local anaesthetics reduced the steady\u2010state level of the intracellular Na activity in a dose\u2010dependent manner. The highest concentrations used (10<jats:sup>\u22122<\/jats:sup> \n<jats:sc>M<\/jats:sc>) reduced the intracellular Na activity by about 25%.<\/jats:p><jats:p>3. TTX decreased the steady\u2010state level of the intracellular Na activity. At a concentration of 10<jats:sup>\u22126<\/jats:sup> g\/ml. (3\u00b713 \u00d7 10<jats:sup>\u22126<\/jats:sup> \n<jats:sc>M<\/jats:sc>), TTX produced a decrease in intracellular Na activity of approximately 10%.<\/jats:p><jats:p>4. The initial rate of rise of the intracellular Na activity upon addition of the cardioactive steroid strophanthidin (10<jats:sup>\u22125<\/jats:sup> \n<jats:sc>M<\/jats:sc>) was used to estimate the net passive Na influx.<\/jats:p><jats:p>5. Procaine (5 \u00d7 10<jats:sup>\u22124<\/jats:sup> \n<jats:sc>M<\/jats:sc>) caused a 50% reduction of this rate of rise of the intracellular Na activity. The highest concentration of procaine used (10<jats:sup>\u22122<\/jats:sup> \n<jats:sc>M<\/jats:sc>) decreased the rate of rise by approximately 80%.<\/jats:p><jats:p>6. Procaine (5 \u00d7 10<jats:sup>\u22123<\/jats:sup> \n<jats:sc>M<\/jats:sc>) also reduced the rate of rise of intracellular Na produced by the removal of external K (K<jats:sub>o<\/jats:sub>), and prevented the large depolarization associated with the absence of K<jats:sub>o<\/jats:sub>.<\/jats:p><jats:p>7. TTX also produced a decrease in the rate of rise of the intracellular Na activity that occurs upon addition of strophanthidin. A maximum effect was produced in our experiments at a TTX concentration of 10<jats:sup>\u22126<\/jats:sup> g\/ml. At this concentration the rate of rise of intracellular Na activity was reduced by approximately 40% at a membrane potential of \u201070 mV.<\/jats:p><jats:p>8. We conclude from our experiments that the effects of local anaesthetics and TTX on the intracellular Na activity are brought about by a reduction of the Na permeability of the cell membrane, and that at the normal resting potential, Na entry through TTX\u2010sensitive channels contributes greatly to the total net Na influx.<\/jats:p>","DOI":"10.1113\/jphysiol.1980.sp013161","type":"journal-article","created":{"date-parts":[[2014,12,19]],"date-time":"2014-12-19T07:24:02Z","timestamp":1418973842000},"page":"269-282","source":"Crossref","is-referenced-by-count":32,"title":["The intracellular sodium activity of sheep heart Purkinje fibres: effects of local anaesthetics and tetrodotoxin"],"prefix":"10.1113","volume":"300","author":[{"given":"Joachim W.","family":"Deitmer","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"David","family":"Ellis","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"311","published-online":{"date-parts":[[1980,3]]},"container-title":["The Journal of Physiology"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/api.wiley.com\/onlinelibrary\/tdm\/v1\/articles\/10.1113%2Fjphysiol.1980.sp013161","content-type":"unspecified","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/physoc.onlinelibrary.wiley.com\/doi\/pdf\/10.1113\/jphysiol.1980.sp013161","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2023,11,5]],"date-time":"2023-11-05T06:35:49Z","timestamp":1699166149000},"score":1,"resource":{"primary":{"URL":"https:\/\/physoc.onlinelibrary.wiley.com\/doi\/10.1113\/jphysiol.1980.sp013161"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1980,3]]},"references-count":0,"journal-issue":{"issue":"1","published-print":{"date-parts":[[1980,3]]}},"alternative-id":["10.1113\/jphysiol.1980.sp013161"],"URL":"https:\/\/doi.org\/10.1113\/jphysiol.1980.sp013161","archive":["Portico"],"relation":{},"ISSN":["0022-3751","1469-7793"],"issn-type":[{"value":"0022-3751","type":"print"},{"value":"1469-7793","type":"electronic"}],"subject":[],"published":{"date-parts":[[1980,3]]}}}