Acta physiologica Scandinavica
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Acta Physiol. Scand. · Aug 1980
Transient vasopressin release and thirst in response to prolonged intracerebroventricular infusions of hypertonic mannitol in saline.
In the conscious goat infusions of 0.4 M mannitol in 0.15 M NaCl into the lateral cerebral ventricle (40 or 100 min, 0.02 ml/min) caused slight, transient vasopressin release and temporary thirst, whereas infusions or pure, hypertonic (0.7 M) mannitol did not elicit thirst and inhibited the basic vasopressin release in the nonhydrated animal. In contrast, infusions of equiosmolal (0.35 M) NaCl induced persistent thirst and pronounced elevation of the plasma vasopressin concentration throughout the infusion period. ⋯ There was no appreciable difference in the CSF K+ concentration after the infusions. The results are discussed with regard to the possible importance of CSF Na+-concentration as opposed to strict osmotic factors for the excitation of receptors involved in the control of water balance.