Effects of drinking on thirst and vasopressin in dehydrated elderly men

P. A. Phillips, M. Bretherton, J. Risvanis, D. Casley, C. Johnston, L. Gray

Research output: Contribution to journalArticle

50 Citations (Scopus)

Abstract

Inhibition of dehydration-induced arginine vasopressin (AVP) secretion and thirst depends on removal of osmotic and hemodynamic stimuli as well as on preabsorptive oropharyngeal factors that reduce thirst and AVP secretion on drinking before correction of the water deficits. Plasma atrial natriuretic peptide (ANP) levels may also change with drinking. Therefore, the thirst and plasma responses to oral water loads (10 ml/kg) in 10 healthy old (64-76 yr) and young (20-32 yr) 24-h water-deprived men were investigated. After 24-h water deprivation plasma sodium, osmolality, and AVP were increased similarly in both groups (P < 0.001). Plasma ANP levels fell after dehydration similarly in both groups (P < 0.05) but were always higher in the older group (P < 0.05). However, although thirst increased in both groups (P < 0.05), this was significantly less in the elderly (P < 0.05). After the water load, thirst was reduced in both groups throughout the study (P < 0.05). However, plasma AVP fell immediately after drinking only in the young group and rose to postdeprivation levels after 15 min. Plasma AVP was not different from postdeprivation throughout in the old group and after 15 min in the young group presumably because the water load was insufficient to replace their water deficits. In the young group only, plasma ANP rose to 182 ± 43% of postdeprivation levels at 3 min after drinking (P < 0.05). These results demonstrate reduced oropharyngeal inhibition of AVP secretion after drinking in healthy elderly men but maintained inhibition of thirst.

Original languageEnglish
Pages (from-to)R877-R881
Number of pages5
JournalAmerican Journal of Physiology - Regulatory Integrative and Comparative Physiology
Volume264
Issue number5
DOIs
Publication statusPublished - 1 May 1993
Externally publishedYes

Keywords

  • aging
  • arginine vasopressin
  • atrial natriuretic peptide

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