Regulation of intracellular pH in sheep cardiac Purkinje fibre: interactions among Na+, H+ and Ca2+
| العنوان: | Regulation of intracellular pH in sheep cardiac Purkinje fibre: interactions among Na+, H+ and Ca2+ |
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| المؤلفون: | Richard D. Vaughan-Jones, C. Bountra, Kai Kaila |
| المصدر: | Canadian Journal of Physiology and Pharmacology. 65:963-969 |
| بيانات النشر: | Canadian Science Publishing, 1987. |
| سنة النشر: | 1987 |
| مصطلحات موضوعية: | Pharmacology, Purkinje fibres, Physiology, Chemistry, medicine.medical_treatment, Intracellular pH, Stimulation, General Medicine, Steroid, Amiloride, Biochemistry, Physiology (medical), medicine, Biophysics, Strophanthidin, Intracellular, medicine.drug |
| الوصف: | Experiments were performed on sheep cardiac Purkinje fibres using pH- and sodium-selective microelectrodes, while simultaneously measuring tension, to determine if the fall in intracellular pH (pHi) following a rise in intracellular Na+ activity [Formula: see text] is caused by inhibition or reversal of acid extrusion on Na+–H+ exhange. A rise in [Formula: see text] was induced either by using the cardioactive steroid strophanthidin to inhibit the sarcolemmal Na+–K+ pump or by increasing the frequency of stimulation (0–4 Hz). Both of these manoeuvres led to an increase in [Formula: see text] and a decrease in pHi. Following exposure to strophanthidin, amiloride (an inhibitor of sarcolemmal Na+–H+ exchange) produced a decrease in both pHi and [Formula: see text]. These effects of amiloride increased with decreasing pHi, indicating that acid extrusion on Na+–H+ exchange is stimulated by the fall in pHi. The changes in intracellular Na+ and H+ caused by amiloride were quantitatively consistent with an electroneutral stoichiometry. The fall in pHi during strophanthidin exposure is therefore not caused by inhibition or reversal of acid extrusion Na+–H+ exchange. It is likely that the fall in pHi during a rate increase is also independent of Na+–H+ exchange. This is because (i) it has been shown previously to occur in the presence of amiloride and (ii) the calcium antagonist D600 completely abolished the stimulation-dependent fall in pHi. It is concluded that the intracellular acidosis following inhibition of the sarcolemmal Na+–K+ pump or following an increase in the rate of stimulation is secondary to a rise in intracellular calcium. |
| تدمد: | 1205-7541 0008-4212 |
| الوصول الحر: | https://explore.openaire.eu/search/publication?articleId=doi_________::5d9af8e797485b721e94b9b15171800bTest https://doi.org/10.1139/y87-153Test |
| حقوق: | CLOSED |
| رقم الانضمام: | edsair.doi...........5d9af8e797485b721e94b9b15171800b |
| قاعدة البيانات: | OpenAIRE |
| تدمد: | 12057541 00084212 |
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