Hypotension- and osmotically induced thirst in old Brown Norway rats

Robert L Thunhorst; Terry G Beltz; Alan Kim Johnson

doi:10.1152/ajpregu.00118.2009

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Hypotension- and osmotically induced thirst in old Brown Norway rats

Journal article

Open access

Peer reviewed

Hypotension- and osmotically induced thirst in old Brown Norway rats

Robert L Thunhorst, Terry G Beltz and Alan Kim Johnson

American journal of physiology. Regulatory, integrative and comparative physiology, Vol.297(1), pp.R149-157

07/2009

DOI: 10.1152/ajpregu.00118.2009

PMCID: PMC2711696

PMID: 19420291

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Abstract

Compared to young cohorts, old rats drink less water in response to several thirst-inducing stimuli. In these experiments, we characterized water drinking in response to hypotension and cellular dehydration in young (4 mo), middle-aged adult (12 mo) and old (29-30 mo) male Brown Norway rats. We injected the vasodilator, minoxidil as an intravenous bolus in a range of doses (0-20 mg/kg), so that drinking responses could be compared at equivalent reductions of arterial pressure. Old rats had greatly diminished reflex tachycardia and became significantly more hypotensive after minoxidil compared with young and middle-aged rats. When compared at equivalent reductions of arterial pressure, old rats drank one-third as much as middle-aged rats, and one-fifth as much as young rats. In addition, there were age-related deficits in drinking in response to a range of administered loads of sodium (0.15-2 M NaCl, 2 ml/100 g body wt). Urinary excretion of water and sodium in response to the loads was equivalent across ages. Both middle-aged and old rats were less able than young rats to repair their water deficits after sodium loading, attributable almost entirely to their reduced drinking responses compared with young rats. Lastly, age-related declines in drinking appeared to be more severe in response to hypotension than in response to cellular dehydration.

Age Factors

Aging

Animals

Blood Pressure

Dehydration - chemically induced

Dehydration - physiopathology

Disease Models, Animal

Diuresis

Drinking

Heart Rate

Hypotension - chemically induced

Hypotension - physiopathology

Male

Minoxidil

Natriuresis

Osmosis

Rats

Rats, Inbred BN

Sodium Chloride

Thirst

Time Factors

Details

Title: Subtitle: Hypotension- and osmotically induced thirst in old Brown Norway rats
Creators: Robert L Thunhorst - Dept. of Psychology, Univ. of Iowa, 11 Seashore Hall E., Iowa City, IA 52242-1407, USA. robert-thunhorst@uiowa.edu
Terry G Beltz
Alan Kim Johnson
Resource Type: Journal article
Publication Details: American journal of physiology. Regulatory, integrative and comparative physiology, Vol.297(1), pp.R149-157
DOI: 10.1152/ajpregu.00118.2009
PMID: 19420291
PMCID: PMC2711696
NLM abbreviation: Am J Physiol Regul Integr Comp Physiol
ISSN: 0363-6119
eISSN: 1522-1490
Grant note: DK-66086 / NIDDK NIH HHS HL-57472 / NHLBI NIH HHS MH-59239 / NIMH NIH HHS HL-14388 / NHLBI NIH HHS AG-25465 / NIA NIH HHS R01 AG025465 / NIA NIH HHS
Language: English
Date published: 07/2009
Academic Unit: Psychological and Brain Sciences; Neuroscience and Pharmacology; Health, Sport, and Human Physiology
Record Identifier: 9984213426902771

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