[Evaluation of the changes in intracranial water, sodium, phosphorus metabolites and intracellular cerebral pH in rats with acute dilutional hyponatremia].
Although most prominent among the clinical manifestations associated with hyponatremia are central nervous system (CNS) symptoms, the alterations in brain function remain poorly understood. In the present study, the alterations in intracellular cerebral pH and intracranial water, sodium and phosphorus metabolites content in rats with acute dilutional hyponatremia were examined by using an in vivo nuclear magnetic resonance (NMR) technique which noninvasively provides continuous informations on intracellular phenomena. Acute dilutional hyponatremia was induced on anesthetized male Sprague-Dawley rats by intraperitoneal injection of distilled water with an initial dose of 10 ml/100 g bw, followed by an additional dose of 5 ml/100 g bw 40 min later. Arterial blood sampling and NMR measurements were made before and every 60 min after the initial injection of distilled water. The treatment with distilled water resulted in dramatic falls in serum Na, Cl and osmolality at 60 min after water loading (Na; from 143.4 +/- 2.6 to 112.3 +/- 1.3 mmol/l, Cl; from 101.02 +/- 2.2 to 78.4 +/- 5.4 mmol/l, Osm; from 306.3 +/- 5.8 to 247.3 +/- 7.3 mOsm/kg H20). 1H-NMR imaging showed the accumulation of brain water as dilutional hyponatremia developed. Intracranial Na content measured by 23Na-NMR spectroscopy decreased significantly at 60 min after of water loading to about 70% of that observed under control condition. Since it has been demonstrated that solute extrusion from the brain with resultant reduction of brain swelling occurs within 60 min after the dilution, this result may be, at least in part, explained by this protective mechanism.(ABSTRACT TRUNCATED AT 250 WORDS)
Uchida
K
K
Second Department of Internal Medicine, Kagawa Medical School.
Takahashi
N
N
Sumikura
T
T
Yura
T
T
Bandai
H
H
Miki
S
S
Yuasa
S
S
Takamitsu
Y
Y
Matsuo
H
H
D000208:Acute Disease; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D001834:Body Water / Q000378:metabolism*; D001921:Brain / Q000166:cytology / Q000378:metabolism*; D004195:Disease Models, Animal; D006863:Hydrogen-Ion Concentration; D007010:Hyponatremia / Q000378:metabolism*; D008297:Male; D010758:Phosphorus / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D012964:Sodium / Q000378:metabolism*
D010758:Phosphorus; D000255:Adenosine Triphosphate; D012964:Sodium