| 10340744 |
Jorgensen NK, Petersen SF, Damgaard I, Schousboe A, Hoffmann EK: Increases in [Ca2+] i and changes in intracellular pH during chemical anoxia in mouse neocortical neurons in primary culture. J Neurosci Res. 1999 May 15;56(4):358-70.
The effect of chemical anoxia (azide) in the presence of glucose on the free intracellular Ca2+ concentration ([Ca2+] i) and intracellular pH (pHi) in mouse neocortical neurons was investigated using Fura-2 and BCECF. Anoxia induced a reversible increase in [Ca2+] i which was significantly inhibited in nominally Ca2+-free medium. A change in pHo (8.2 or 6.6), or addition of NMDA and non-NMDA receptor antagonists (D-AP5 and CNQX) in combination, significantly reduced the increase in [Ca2+] i, pointing to a protective effect of extracellular alkalosis or acidosis, and involvement of excitatory amino acids. An initial anoxia-induced acidification was observed under all experimental conditions. In the control situation, this acidification was followed by a recovery/alkalinization of pHi in about 50% of the cells, a few cells showed no recovery, and some showed further acidification. EIPA, an inhibitor of Na+/H+ exchangers, prevented alkalinization, pointing towards anoxia-induced activation of a Na+/H+ exchanger. In a nominally Ca2+-free medium, the initial acidification was followed by a significant alkalinization. At pHo 8.2, the alkalinization was significantly increased, while at pHo 6.2, the initial acidification was followed by further acidification in about 50% of the cells, and by no further change in the remaining cells. |
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