Abstract

(Verbatim from the application): In the hind limb unweighted (HU) rat model of bed rest and microgravity, HU results in a central movement of body fluid, diuresis and natriuresis, resulting in a decrease in plasma volume. We have observed that rats increase ingestion of saline solution during 24h HU. Further, this ingestion of saline inhibits the decrease in plasma volume normally observed in 24h HU rats. The studies proposed examine the integration of neural and humoral factors influencing sodium ingestion in the HU model of bed rest.
The specific aims of the study are:
Specific aim 1 : Investigate the role of the renal nerves in promoting sodium intake during 24 h HU.
Specific aim 2 : Investigate the role of hormones in promoting sodium intake during HU.
Specific aim 3 : Examine the role of the cardiac afferent nerves in regulating the intake of sodium.
Specific aim 4 : Compare short term (24 h) and long term (14 d) effects of HU on sodium ingestion and plasma volume. We hypothesize that increases in renal afferent nerve activity is critical to HU-induced sodium ingestion. Furthermore, elevated aldosterone may contribute to the ingestion of sodium while stimulation of cardiac afferent nerves may inhibit sodium intake in this model. Integration of these signals by the central nervous system results in a modest sodium intake and maintains plasma volume during HU. During prolonged HU, adaptations may occur which further influence both the ingestion of sodium and blood volume. Understanding bed rest and microgravity-induced changes in body fluid balance requires understanding such factors as the acquisition of solutes. It is hoped that these experiments will contribute to an understanding of both the regulation of body fluid during prolonged bed rest and the problems associated with return to normal posture. Additionally, these data may contribute to understanding of health problems associated with an aging population and with cardiovascular disease such as congestive heart failure.

  Funding Agency

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK057822-06
Application #
6844307
Study Section
Experimental Cardiovascular Sciences Study Section (ECS)
Program Officer
Ketchum, Christian J
Project Start
2001-02-01
Project End
2007-01-31
Budget Start
2005-02-01
Budget End
2007-01-31
Support Year
6
Fiscal Year
2005
Total Cost
$186,150
Indirect Cost

  Institution

Name
University of Texas Health Science Center San Antonio
Department
Pharmacology
Type
Other Domestic Higher Education
DUNS #
800772162
City
San Antonio
State
TX
Country
United States
Zip Code
78229

  Publications

Yao, S T; Gouraud, S S; Qiu, J et al. (2012) Selective up-regulation of JunD transcript and protein expression in vasopressinergic supraoptic nucleus neurones in water-deprived rats. J Neuroendocrinol 24:1542-52
Ji, Lisa L; Gottlieb, Helmut B; Penny, Maurice L et al. (2007) Differential effects of water deprivation and rehydration on Fos and FosB/DeltaFosB staining in the rat brainstem. Exp Neurol 203:445-56
Gottlieb, H B; Fleming, T M; Ji, L et al. (2007) Identification of central nervous system sites involved in the water diuresis response elicited by central microinjection of nociceptin/ Orphanin FQ in conscious rats via c-Fos and inducible cAMP early repressor immunocytochemistry. J Neuroendocrinol 19:531-42
Cunningham, J Thomas; Herrera-Rosales, Myrna; Martinez, Michelle A et al. (2007) Identification of active central nervous system sites in renal wrap hypertensive rats. Hypertension 49:653-8
Mueller, Patrick J; Sullivan, Margaret J; Grindstaff, Regina R et al. (2006) Regulation of plasma vasopressin and renin activity in conscious hindlimb-unloaded rats. Am J Physiol Regul Integr Comp Physiol 291:R46-52
Gottlieb, Helmut B; Ji, Lisa L; Jones, Heath et al. (2006) Differential effects of water and saline intake on water deprivation-induced c-Fos staining in the rat. Am J Physiol Regul Integr Comp Physiol 290:R1251-61
Penny, Maurice L; Bruno, Stacy B; Cornelius, Jennifer et al. (2005) The effects of osmotic stimulation and water availability on c-Fos and FosB staining in the supraoptic and paraventricular nuclei of the hypothalamus. Exp Neurol 194:191-202
Ji, Lisa L; Fleming, Tiffany; Penny, Maurice L et al. (2005) Effects of water deprivation and rehydration on c-Fos and FosB staining in the rat supraoptic nucleus and lamina terminalis region. Am J Physiol Regul Integr Comp Physiol 288:R311-21
Howe, B Matthew; Bruno, Stacy B; Higgs, Karen A N et al. (2004) FosB expression in the central nervous system following isotonic volume expansion in unanesthetized rats. Exp Neurol 187:190-8
Cunningham, J Thomas; Penny, Maurice L; Murphy, David (2004) Cardiovascular regulation of supraoptic neurons in the rat: synaptic inputs and cellular signals. Prog Biophys Mol Biol 84:183-96

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