title: Differential effects of mineralocorticoid and angiotensin II on incentive and mesolimbic activity.
abstract: The controls of thirst and sodium appetite are mediated in part by the hormones aldosterone and angiotensin II (AngII). The present study examined the behavioral and neural mechanisms of altered effort-value in animals treated with systemic mineralocorticoids, intracerebroventricular AngII, or both. First, rats treated with mineralocorticoid and AngII were tested in the progressive ratio operant task. The willingness to work for sodium versus water depended on hormonal treatment. In particular, rats treated with both mineralocorticoid and AngII preferentially worked for access to sodium versus water compared with rats given only one of these hormones. Second, components of the mesolimbic dopamine pathway were examined for modulation by mineralocorticoids and AngII. Based on cFos immunohistochemistry, AngII treatment activated neurons in the ventral tegmental area and nucleus accumbens, with no enhancement by mineralocorticoid pretreatment. In contrast, Western blot analysis revealed that combined hormone treatment increased levels of phospho-tyrosine hydroxylase in the ventral tegmental area. Thus, mineralocorticoid and AngII treatments differentially engaged the mesolimbic pathway based on tyrosine hydroxylase levels versus cFos activation.
authors.affiliation: Neuroscience Graduate Group, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
authors.forename: Laura A
authors.initials: LA
authors.lastname: Grafe
authors.affiliation: Neuroscience Graduate Group, University of Pennsylvania, Philadelphia, Pennsylvania, USA; Department of Psychology, University of Pennsylvania, Philadelphia, Pennsylvania, USA; Mahoney Institute of Neurological Sciences, University of Pennsylvania, Philadelphia, Pennsylvania, USA. Electronic address: flanagan@psych.upenn.edu.
authors.forename: Loretta M
authors.initials: LM
authors.lastname: Flanagan-Cato
mesh_terms: D000804:Angiotensin II / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D004298:Dopamine / Q000502:physiology; D057967:Infusions, Intraventricular; D008032:Limbic System / Q000187:drug effects* / Q000502:physiology; D008297:Male; D008901:Mineralocorticoids / Q000008:administration & dosage / Q000494:pharmacology*; D009042:Motivation / Q000187:drug effects*; D009474:Neurons / Q000187:drug effects / Q000378:metabolism; D009714:Nucleus Accumbens / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism; D017557:Ventral Tegmental Area / Q000187:drug effects / Q000378:metabolism
chemical_list: D008901:Mineralocorticoids; D000804:Angiotensin II; D014446:Tyrosine 3-Monooxygenase; D004298:Dopamine
keywords: Aldosterone; Angiotensin; Dopamine; Motivation; Nucleus accumbens; Sodium appetite; Thirst; Ventral tegmental area