OBJECTIVE: Centrally released @entity5463 (AVP) and @entity12579 (ANP) have been shown to participate in brain volume regulation. The aim of the present study was to evaluate the effects of centrally administered AVP and ANP on the time course of development of @entity2657 in vivo in hyponatremic @entity35 , using diffusion-weighted magnetic resonance imaging. METHODS: We performed intracerebroventricular (ICV) administration of 120 microg AVP, 20 microg ANP, or physiological saline into the right lateral ventricle in 18 @entity35 . Twenty-five minutes after the treatment, we induced systemic @entity2753 by the intraperitoneal administration of 140 mmol/L @entity413 solution. Serial diffusion-weighted imaging scans were obtained up to 96 minutes after the start of the @entity2753 . Changes in the brain extra-to intracellular volume fraction ratio were estimated as changes in the apparent diffusion coefficient (ADC). RESULTS: No change in the ADC was observed after the ICV injection of saline or @entity1831 . The onset of @entity2753 induced a rapid and marked @entity353 in both groups, indicating an increased intracellular space. However, the ADC decrease became significantly more pronounced in the ICV AVP group (83.3+/-4.7% of baseline level, mean +/- standard deviation) than in the saline group (93.7+/-3.3% of baseline, P < 0.001) after 78 minutes of @entity2753 . The ICV injection of ANP induced a prompt ADC increase to 111.5+/-10.0% (P < 0.05) of the baseline level, indicating a rapid reduction in the intracellular compartment. In the initial phase of @entity2753 , the ADC values in the ANP group were consistently higher than those in the saline group, decreasing finally to 86.9+/-9.6% after 96 minutes of @entity2753 . CONCLUSION: Our findings demonstrate the opposite effects of AVP and ANP on the intracellular volume fraction of the brain during the development of cellular @entity2657 , with an immediate effect on ANP and a delayed effect on AVP. The results emphasize the direct effects of these hormones on the cellular volume regulatory mechanisms in the brain during the development of @entity2657 .

Effects of centrally administered @entity5463 and @entity12579 on the development of @entity2657 in hyponatremic XXXX .

@entity1831 :: ('CHEBI:34543', 'Chemical') :: ['AVP'] @entity2657 :: ('MESH:D001929', 'Disease') :: ['cerebral edema', 'brain edema'] @entity353 :: ('MESH:D015431', 'Disease') :: ['ADC reduction'] @entity5463 :: ('MESH:D001127', 'Chemical') :: ['arginine vasopressin'] @entity413 :: ('MESH:D005947', 'Chemical') :: ['dextrose'] @entity12579 :: ('24602(Tax:10116)', 'Gene') :: ['atrial natriuretic peptide'] @entity35 :: ('10116', 'Species') :: ['rats'] @entity2753 :: ('MESH:D007010', 'Disease') :: ['hyponatremia']
@entity35 :: (10116,Species) :: ['rats']
