Osmotic injury induced by rapid correction of severe chronic hyponatremia has been implicated in the development of central pontine myelinolysis. Organic osmolytes known previously as "idiogenic osmoles" accumulate intracellularly to protect cells from osmotic injury. We investigated the changes of these organic osmolytes as well as electrolytes in the brain during the induction and correction of chronic hyponatremia. Using 1H-nuclear magnetic resonance spectroscopy and HPLC, we found that in rats with chronic hyponatremia (3 d, serum sodium = 109 +/- 3 meq/liter), brain concentrations of myoinositol (41%), glycerophosphorylcholine (45%), phosphocreatine/creatine (60%), glutamate (53%), glutamine (45%), and taurine (37%) were all significantly decreased compared with control values (percentage control value shown, all P less than 0.01). The contribution of measured organic osmolytes and electrolytes to the total brain osmolality change was 23 and 72%, respectively. With rapid correction by 5% NaCl infusion, significant brain dehydration and elevation of brain Na and Cl levels above the normal range occurred at 24 h. These changes were not seen with slow correction by water deprivation. Reaccumulation of most organic osmolytes except glycerophosphorylcholine is delayed during the correction of hyponatremia and is independent of the correction rate of serum sodium. It is concluded that: most of the change of brain osmolality in chronic hyponatremia can be accounted by the changes in organic osmolytes and brain electrolytes; and rapid correction of hyponatremia is associated with an overshoot of brain sodium and chloride levels along with a low organic osmolyte level. The high cerebral ion concentrations in the absence of adequate concentrations of organic osmolytes may be relevant to the development of central pontine myelinolysis.
Y H Lien, J I Shapiro, L Chan
Usage data is cumulative from March 2023 through March 2024.
Usage | JCI | PMC |
---|---|---|
Text version | 285 | 0 |
84 | 69 | |
Scanned page | 145 | 26 |
Citation downloads | 9 | 0 |
Totals | 523 | 95 |
Total Views | 618 |
Usage information is collected from two different sources: this site (JCI) and Pubmed Central (PMC). JCI information (compiled daily) shows human readership based on methods we employ to screen out robotic usage. PMC information (aggregated monthly) is also similarly screened of robotic usage.
Various methods are used to distinguish robotic usage. For example, Google automatically scans articles to add to its search index and identifies itself as robotic; other services might not clearly identify themselves as robotic, or they are new or unknown as robotic. Because this activity can be misinterpreted as human readership, data may be re-processed periodically to reflect an improved understanding of robotic activity. Because of these factors, readers should consider usage information illustrative but subject to change.