Body fluid homeostasis depends on reflexes that modulate the rate of renal water and sodium loss and on ingestive behaviors (i.e., thirst and salt appetite) that correct homeostatic deficits. Although renal mechanisms slow fluid loss, the restoration of vascular volume depends on the ingestion of water and solute (e.g., sodium). The maintenance of extracellular volume requires that the central nervous system (CNS) receives and processes information about the status of body water and sodium. Several visceral sensory systems provide this afferent input, but there is only a very limited understanding about how this information is handled by the CNS. The present proposal builds upon our prior studies that have been directed at defining the nature of interactions of afferent signals involved in body fluid and cardiovascular homeostasis and at understanding the CNS processing mechanisms of such afferent information. Recently, we have used the mouse to investigate several issues related to body fluid and cardiovascular homeostasis. Use of this species was prompted by the potential of new experimental models derived by manipulation of the mouse genome. Several of our initial studies have adapted and validated many of the conventional experimental manipulations used to study thirst and salt appetite in rat. The results indicate that there are many important similarities between mouse and other experimental species, and also provocative differences. We propose studies in normal mice that allow us to clarify understanding of the control of thirst and salt appetite in this species. In addition we propose studies that take advantage of currently available mouse models to generate important new information about the basic neurobiology of thirst and salt appetite. Specifically, we will study the interaction of the systemic and brain renin-angiotensin-aldosterone systems and blood pressure in the control of their behaviors that contribute to body fluid homeostasis. Initial studies will employ methods and knowledge derived from studying wild type mice to further understanding of the role of body and brain renin-angiotensin systems in the behavioral control of body fluid balance. Other studies will make use of a mouse transgenic model developed at the University of Iowa that over-expresses angiotensin type 1 receptors in brain and in sensory circumventricular organ neurons. Information generated from these studies will be relevant to the well-being of normal individuals exposed to physiological (e.g., exercise) and environmental (e.g., heat) challenges. These studies will be especially important for understanding mechanisms underlying pathological conditions such as hypertension and congestive heart failure where excess thirst and sodium intake have been documented.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK066086-05
Application #
7575101
Study Section
Neuroendocrinology, Neuroimmunology, and Behavior Study Section (NNB)
Program Officer
Malozowski, Saul N
Project Start
2005-03-01
Project End
2011-01-31
Budget Start
2009-02-01
Budget End
2011-01-31
Support Year
5
Fiscal Year
2009
Total Cost
$289,882
Indirect Cost
Name
University of Iowa
Department
Psychology
Type
Schools of Arts and Sciences
DUNS #
062761671
City
Iowa City
State
IA
Country
United States
Zip Code
52242
Thunhorst, Robert L; Beltz, Terry; Johnson, Alan Kim (2014) Age-related declines in thirst and salt appetite responses in male Fischer 344×Brown Norway rats. Physiol Behav 135:180-8
Thunhorst, Robert L; Beltz, Terry G; Johnson, Alan Kim (2013) Effects of aging on mineralocorticoid-induced salt appetite in rats. Am J Physiol Regul Integr Comp Physiol 305:R1498-505
Na, Elisa S; Morris, Michael J; Johnson, Alan Kim (2012) Opioid mechanisms that mediate the palatability of and appetite for salt in sodium replete and deficient states. Physiol Behav 106:164-70
Morris, Michael J; Na, Elisa S; Johnson, Alan Kim (2012) Voluntary running-wheel exercise decreases the threshold for rewarding intracranial self-stimulation. Behav Neurosci 126:582-7
Lamkin, Donald M; Lutgendorf, Susan K; Lubaroff, David et al. (2011) Cancer induces inflammation and depressive-like behavior in the mouse: modulation by social housing. Brain Behav Immun 25:555-64
Xue, Baojian; Beltz, Terry G; Yu, Yang et al. (2011) Central interactions of aldosterone and angiotensin II in aldosterone- and angiotensin II-induced hypertension. Am J Physiol Heart Circ Physiol 300:H555-64
Singh, M; Singh, M M; Na, E et al. (2011) Altered ADAR 2 equilibrium and 5HT(2C) R editing in the prefrontal cortex of ADAR 2 transgenic mice. Genes Brain Behav 10:637-47
Thunhorst, Robert L; Grobe, Connie L; Beltz, Terry G et al. (2011) Effects of ?-adrenergic receptor agonists on drinking and arterial blood pressure in young and old rats. Am J Physiol Regul Integr Comp Physiol 300:R1001-8
Acerbo, Martin J; Johnson, Alan Kim (2011) Behavioral cross-sensitization between DOCA-induced sodium appetite and cocaine-induced locomotor behavior. Pharmacol Biochem Behav 98:440-8
Grobe, Justin L; Grobe, Connie L; Beltz, Terry G et al. (2010) The brain Renin-angiotensin system controls divergent efferent mechanisms to regulate fluid and energy balance. Cell Metab 12:431-42

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