| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Institute of Biophysics, University of Aarhus, Denmark.
1. The pH-sensitive dye 2',7'-bis-(2-carboxyethyl)-5 (and -6)-carboxyfluorescein (BCECF) was used to measure intracellular pH (pHi) in segments of rat resistance vessels (internal diameter about 200 microns) with the vessels mounted in a myograph for simultaneous measurements of isometric contraction. 2. BCECF loaded slowly into the vessels over 1 h and did not affect the maximal contractility of the vessels. There was a loss of dye with time which, however, was very slow when the segments were only excited for 2 s/min, suggesting that the loss was mainly due to dye bleaching with only a very slow leak. 3. The ratio of the emissions (at 540 nm) with excitation at 495 and 450 nm was calibrated in terms of pH using the K+-H+ ionophore nigericin. This calibration gave a pHi value of 7.15 +/- 0.02 (n = 20), suggesting that hydrogen ions are not in electrochemical equilibrium in these vascular smooth muscles which have a membrane potential of about -60 mV. 4. Addition of 10 mM-NH4Cl caused a transient alkalinization and wash-out of 10 mM-NH4Cl a transient acidification. Increasing CO2 with maintained bicarbonate caused a rapid acidification followed by an incomplete recovery. Removal of CO2 and bicarbonate (HEPES-buffered solution) with constant extracellular pH caused a transient alkalinization but steady-state pHi was not significantly altered. 5. In bicarbonate-free buffer the Na+-H+ exchange blocker 5-(N-ethyl-N-isopropyl) amiloride (EIPA) and sodium-free conditions caused a slow acidification. In bicarbonate buffer (PSS) EIPA had no detectable effect after 10 min but the anion exchange blocker diisothio-cyanatostilbenedisulphonic acid (DIDS) caused a small acidification over that time course. 6. The rate of recovery after an acid load was about 50% lower in HEPES buffer compared to PSS and it was inhibited by EIPA. In PSS amiloride and EIPA each had a small inhibitory effect on the pH recovery after an acid load. DIDS also inhibited the recovery from an acid load in PSS and this effect was additive to that of EIPA. DIDS and EIPA also had additive inhibitory effects on the 22Na+ influx stimulated by the acid loading, while in HEPES buffer DIDS had no effect on either pH recovery or 22Na+ influx. These results suggest that a Na+-H+ exchange and an influx of bicarbonate coupled to sodium influx are of importance for pHi control in these vessels.(ABSTRACT TRUNCATED AT 400 WORDS)
This article has been cited by other articles:
|
|
 |
|
  E. Boedtkjer, J. Praetorius, E.-M. Fuchtbauer, and C. Aalkjaer Antibody-independent localization of the electroneutral Na+-HCO3- cotransporter NBCn1 (slc4a7) in mice Am J Physiol Cell Physiol, February 1, 2008; 294(2): C591 - C603. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 E. Boedtkjer, J. Praetorius, and C. Aalkjaer NBCn1 (slc4a7) Mediates the Na+-Dependent Bicarbonate Transport Important for Regulation of Intracellular pH in Mouse Vascular Smooth Muscle Cells Circ. Res., March 3, 2006; 98(4): 515 - 523. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 H. H. Damkier, S. Nielsen, and J. Praetorius An anti-NH2-terminal antibody localizes NBCn1 to heart endothelia and skeletal and vascular smooth muscle cells Am J Physiol Heart Circ Physiol, January 1, 2006; 290(1): H172 - H180. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 E. J. Rios, M. Fallon, J. Wang, and L. A. Shimoda Chronic hypoxia elevates intracellular pH and activates Na+/H+ exchange in pulmonary arterial smooth muscle cells Am J Physiol Lung Cell Mol Physiol, November 1, 2005; 289(5): L867 - L874. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. Vankova, V. A. Snetkov, G. A. Knock, P. I. Aaronson, and J. P.T. Ward Euhydric hypercapnia increases vasoreactivity of rat pulmonary arteries via HCO3- transport and depolarisation Cardiovasc Res, February 1, 2005; 65(2): 505 - 512. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. Sandmann, M. Yu, E. Kaschina, A. Blume, E. Bouzinova, C. Aalkjaer, and T. Unger Differential effects of angiotensin AT1 and AT2 receptors on the expression, translation and function of the Na+-H+ exchanger and Na+-HCO3- symporter in the rat heart after myocardial infarction J. Am. Coll. Cardiol., June 15, 2001; 37(8): 2154 - 2165. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. Austin and S. Wray Interactions Between Ca2+ and H+ and Functional Consequences in Vascular Smooth Muscle Circ. Res., February 18, 2000; 86(3): 355 - 363. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. Pushkin, K.-P. Yip, I. Clark, N. Abuladze, T.-H. Kwon, S. Tsuruoka, G. J. Schwartz, S. Nielsen, and I. Kurtz NBC3 expression in rabbit collecting duct: colocalization with vacuolar H+-ATPase Am J Physiol Renal Physiol, December 1, 1999; 277(6): F974 - F981. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. Pushkin, N. Abuladze, I. Lee, D. Newman, J. Hwang, and I. Kurtz Cloning, Tissue Distribution, Genomic Organization, and Functional Characterization of NBC3, a New Member of the Sodium Bicarbonate Cotransporter Family J. Biol. Chem., June 4, 1999; 274(23): 16569 - 16575. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. Sweeney, D. Beddy, V. Honner, B. Sinnott, R. G. O'Regan, and P. McLoughlin Effects of changes in pH and CO2 on pulmonary arterial wall tension are not endothelium dependent J Appl Physiol, December 1, 1998; 85(6): 2040 - 2046. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G.L. Smith, C. Austin, C. Crichton, and S. Wray A review of the actions and control of intracellular pH in vascular smooth muscle Cardiovasc Res, May 1, 1998; 38(2): 316 - 331. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
H. J. Majima, T. D. Oberley, K. Furukawa, M. P. Mattson, H.-C. Yen, L. I. Szweda, and D. K. St. Clair Prevention of Mitochondrial Injury by Manganese Superoxide Dismutase Reveals a Primary Mechanism for Alkaline-induced Cell Death J. Biol. Chem., April 3, 1998; 273(14): 8217 - 8224. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
H.-L. Peng, P. E. Jensen, H. Nilsson, and C. Aalkjar Effect of acidosis on tension and [Ca2+]i in rat cerebral arteries: is there a role for membrane potential? Am J Physiol Heart Circ Physiol, February 1, 1998; 274(2): H655 - H662. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 X.-L. Chen and C. M. Rembold pHi, [Ca2+]i, and Myosin Phosphorylation in Histamine- and NH4+-Induced Swine Carotid Artery Contraction Hypertension, April 1, 1995; 25(4): 482 - 489. [Abstract] [Full Text]
|
|
|
|
|
|
R. Tian, P. Vogel, N. A. Lassen, M. J. Mulvany, F. Andreasen, and C. Aalkjær Role of Extracellular and Intracellular Acidosis for Hypercapnia-Induced Inhibition of Tension of Isolated Rat Cerebral Arteries Circ. Res., February 1, 1995; 76(2): 269 - 275. [Abstract] [Full Text]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
