title: Continuous measurement of Na concentration in CSF during gastric water infusion in dehydrated rats.
abstract: To assess the differential stimulus to central and intravascular osmoreceptors during recovery from thermal dehydration, we measured Na concentrations in cerebrospinal fluid ([Na]CSF) and plasma ([Na]p) continuously and compared these during simulated drinking by gastric water infusion (INF) in euhydrated and thermally dehydrated rats under anesthesia. Continuous measurement of [Na]CSF was obtained with a double-barreled Na electrode placed in the lateral ventricle. Continuous measurement of [Na]p was obtained from a flow cell Na electrode in an extracorporeal shunt. Measurements were made during 10 min of INF (2.5 ml/100 g body wt) into the stomach and during 20 min of recovery. Changes in [Na]CSF always lagged behind those in [Na]p and were quantitatively smaller after INF. The decrease in [Na]CSF occurred sooner in dehydrated than in euhydrated rats in response to the decrease in [Na]p (P < 0.01). These results suggest that water and/or Na movement between blood and CSF is accelerated during restitution from thermal dehydration, acting to prevent overhydration during the early phase of rehydration.
authors.affiliation: Department of Physiology, Kyoto Prefectural University of Medicine, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Nose
authors.forename: Y
authors.initials: Y
authors.lastname: Doi
authors.forename: S
authors.initials: S
authors.lastname: Usui
authors.forename: T
authors.initials: T
authors.lastname: Kubota
authors.forename: M
authors.initials: M
authors.lastname: Fujimoto
authors.forename: T
authors.initials: T
authors.lastname: Morimoto
mesh_terms: D000818:Animals; D002552:Cerebral Ventricles / Q000378:metabolism; D003681:Dehydration / Q000097:blood / Q000134:cerebrospinal fluid / Q000378:metabolism*; D004566:Electrodes; D004594:Electrophysiology; D005440:Fluid Therapy; D006321:Heart / Q000502:physiology; D007441:Intubation, Gastrointestinal; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D012964:Sodium / Q000097:blood / Q000134:cerebrospinal fluid*; D013238:Stereotaxic Techniques
chemical_list: D012964:Sodium