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Extracellular pH in the rat brain during hypoglycemic coma and recovery.
J Cereb Blood Flow Metab. 1990 Mar; 10(2):262-9.JC

Abstract

It has previously been shown that hypoglycemic coma is accompanied by marked energy failure and by loss of cellular ionic homeostasis. The general proposal is that shortage of carbohydrate substrate prevents lactic acid formation and thereby acidosis during hypoglycemic coma. The objective of the present study was to explore whether rapid downhill ion fluxes, known to occur during coma, are accompanied by changes in extra- and/or intracellular pH (pHe and/or pHi), and how these relate to the de- and repolarization of cellular membranes. Cortical pHe was recorded by microelectrodes in insulin-injected rats subjected to 30 min of hypoglycemic coma, with cellular membrane depolarization. Some rats were allowed up to 180 min of recovery after glucose infusion and membrane repolarization. Arterial blood gases and physiological parameters were monitored to maintain normotension, normoxia, normocapnia, and normal plasma pH. Following depolarization during hypoglycemia, a prompt, rapidly reversible alkaline pHe shift of about 0.1 units was observed in 37/43 rats. Immediately thereafter, all rats showed an acid pH shift of about 0.2 units. This shift developed during the first minute, and pHe remained at that level until repolarization was induced. Following repolarization, there was an additional, rapid, further lowering of pHe by about 0.05 units, followed by a more prolonged decrease in pHe that was maximal at 90 min of recovery (delta pHe of approximately -0.4 units). The pHe then slowly normalized but was still decreased (-0.18 pH units) after 180 min when the experiment was terminated. The calculated pHi showed no major alterations during hypoglycemic coma or after membrane repolarization following glucose administration.(ABSTRACT TRUNCATED AT 250 WORDS)

Authors+Show Affiliations

Laboratory for Experimental Brain Research, Lund University, Sweden.No affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

2303542

Citation

Bengtsson, F, et al. "Extracellular pH in the Rat Brain During Hypoglycemic Coma and Recovery." Journal of Cerebral Blood Flow and Metabolism : Official Journal of the International Society of Cerebral Blood Flow and Metabolism, vol. 10, no. 2, 1990, pp. 262-9.
Bengtsson F, Boris-Möller F, Hansen AJ, et al. Extracellular pH in the rat brain during hypoglycemic coma and recovery. J Cereb Blood Flow Metab. 1990;10(2):262-9.
Bengtsson, F., Boris-Möller, F., Hansen, A. J., & Siesjö, B. K. (1990). Extracellular pH in the rat brain during hypoglycemic coma and recovery. Journal of Cerebral Blood Flow and Metabolism : Official Journal of the International Society of Cerebral Blood Flow and Metabolism, 10(2), 262-9.
Bengtsson F, et al. Extracellular pH in the Rat Brain During Hypoglycemic Coma and Recovery. J Cereb Blood Flow Metab. 1990;10(2):262-9. PubMed PMID: 2303542.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Extracellular pH in the rat brain during hypoglycemic coma and recovery. AU - Bengtsson,F, AU - Boris-Möller,F, AU - Hansen,A J, AU - Siesjö,B K, PY - 1990/3/1/pubmed PY - 1990/3/1/medline PY - 1990/3/1/entrez SP - 262 EP - 9 JF - Journal of cerebral blood flow and metabolism : official journal of the International Society of Cerebral Blood Flow and Metabolism JO - J Cereb Blood Flow Metab VL - 10 IS - 2 N2 - It has previously been shown that hypoglycemic coma is accompanied by marked energy failure and by loss of cellular ionic homeostasis. The general proposal is that shortage of carbohydrate substrate prevents lactic acid formation and thereby acidosis during hypoglycemic coma. The objective of the present study was to explore whether rapid downhill ion fluxes, known to occur during coma, are accompanied by changes in extra- and/or intracellular pH (pHe and/or pHi), and how these relate to the de- and repolarization of cellular membranes. Cortical pHe was recorded by microelectrodes in insulin-injected rats subjected to 30 min of hypoglycemic coma, with cellular membrane depolarization. Some rats were allowed up to 180 min of recovery after glucose infusion and membrane repolarization. Arterial blood gases and physiological parameters were monitored to maintain normotension, normoxia, normocapnia, and normal plasma pH. Following depolarization during hypoglycemia, a prompt, rapidly reversible alkaline pHe shift of about 0.1 units was observed in 37/43 rats. Immediately thereafter, all rats showed an acid pH shift of about 0.2 units. This shift developed during the first minute, and pHe remained at that level until repolarization was induced. Following repolarization, there was an additional, rapid, further lowering of pHe by about 0.05 units, followed by a more prolonged decrease in pHe that was maximal at 90 min of recovery (delta pHe of approximately -0.4 units). The pHe then slowly normalized but was still decreased (-0.18 pH units) after 180 min when the experiment was terminated. The calculated pHi showed no major alterations during hypoglycemic coma or after membrane repolarization following glucose administration.(ABSTRACT TRUNCATED AT 250 WORDS) SN - 0271-678X UR - https://www.unboundmedicine.com/medline/citation/2303542/Extracellular_pH_in_the_rat_brain_during_hypoglycemic_coma_and_recovery_ DB - PRIME DP - Unbound Medicine ER -