Water deprivation-induced sodium appetite and differential expression of encephalic c-Fos immunoreactivity in the spontaneously hypertensive rat

The spontaneously hypertensive rat (SHR) has an intense consumption of NaCl solution. Water deprivation (WD) followed by water intake to satiety induces partial rehydration (PR)—the WD-PR protocol—and sodium appetite. In the present work, WD produced similar water intake and no alterations in arterial pressure among spontaneously hypertensive rat (SHR), Wistar-Kyoto, and Holtzman strains. It also increased the number of cells with positive c-Fos immunoreactivity (Fos-IR) in the lamina terminalis and in the hypothalamic supraoptic (SON) and paraventricular (parvocellular, PVNp) nucleus in these strains. The WD and WD-PR produced similar alterations in all strains in serum osmolality and protein, plasma renin activity, and sodium balance. The SHR ingested about 10 times more 0.3 M NaCl than normotensives strains in the sodium appetite test that follows WD-PR. After WD-PR, the Fos-IR persisted, elevated in the lamina terminalis of all strains but notably in the subfornical organ of the SHR. The WD-PR reversed Fos-IR in the SON of all strains and in the PVNp of SHR. It induced Fos-IR in the area postrema and in the nucleus of the solitary tract (NTS), dorsal raphe, parabrachial (PBN), pre-locus coeruleus (pre-LC), suprachiasmatic, and central amygdalar nucleus of all strains. This effect was bigger in the caudal-NTS, pre-LC, and medial-PBN of SHRs. The results indicate that WD-PR increases cell activity in the forebrain and hindbrain areas that control sodium appetite in the rat. They also suggest that increased cell activity in facilitatory brain areas precedes the intense 0.3 M NaCl intake of the SHR in the sodium appetite test.

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Relationship between sodium balance and renal innervation during hypertension development in the spontaneously hypertensive rat

Journal of Hypertension ◽

10.1097/00004872-199412000-00007 ◽

1994 ◽

Vol 12 (12) ◽

pp. 1359???1364 ◽

Cited By ~ 6

Author(s):

Suzanne Greenberg ◽

Jeffrey L. Osborn

Keyword(s):

Spontaneously Hypertensive Rat ◽

Sodium Balance ◽

Spontaneously Hypertensive ◽

Hypertensive Rat ◽

Renal Innervation ◽

Hypertension Development

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EFFECT OF CROSS-FOSTERING ON NEONATAL SODIUM BALANCE AND ADULT BLOOD PRESSURE IN THE SPONTANEOUSLY HYPERTENSIVE RAT

Clinical and Experimental Pharmacology and Physiology ◽

10.1111/j.1440-1681.1998.tb02178.x ◽

1998 ◽

Vol 25 (12) ◽

pp. 1024-1031 ◽

Cited By ~ 14

Author(s):

Ingrid Gouldsborough ◽

Nick Ashton

Keyword(s):

Blood Pressure ◽

Spontaneously Hypertensive Rat ◽

Sodium Balance ◽

Spontaneously Hypertensive ◽

Hypertensive Rat ◽

Cross Fostering

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Water deprivation-partial rehydration induces sensitization of sodium appetite and alteration of hypothalamic transcripts

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.00501.2014 ◽

2016 ◽

Vol 310 (1) ◽

pp. R15-R23 ◽

Cited By ~ 4

Author(s):

Daniela T. B. Pereira-Derderian ◽

Regina C. Vendramini ◽

José V. Menani ◽

Silvana Chiavegatto ◽

Laurival A. De Luca

Keyword(s):

Water Deprivation ◽

Behavioral Plasticity ◽

Spontaneously Hypertensive Rat ◽

Sodium Intake ◽

Renin Angiotensin System ◽

Male Adult ◽

Spontaneously Hypertensive ◽

Sodium Appetite ◽

Wistar Kyoto ◽

The Brain

iSodium intake occurs either as a spontaneous or induced behavior, which is enhanced, i.e., sensitized, by repeated episodes of water deprivation followed by subsequent partial rehydration (WD-PR). In the present work, we examined whether repeated WD-PR alters hypothalamic transcripts related to the brain renin-angiotensin system (RAS) and apelin system in male normotensive Holtzman rats (HTZ). We also examined whether the sodium intake of a strain with genetically inherited high expression of the brain RAS, the spontaneously hypertensive rat (SHR), responds differently than HTZ to repeated WD-PR. We found that repeated WD-PR, besides enhancing spontaneous and induced 0.3 M NaCl intake, increased the hypothalamic expression of angiotensinogen, aminopeptidase N, and apelin receptor transcripts (43%, 60%, and 159%, respectively) in HTZ at the end of the third WD-PR. Repeated WD-PR did not change the daily spontaneous 0.3 M NaCl intake and barely changed the need-induced 0.3 M NaCl intake of SHR. The same treatment consistently enhanced spontaneous daily 0.3 M NaCl intake in the normotensive Wistar-Kyoto rats. The results show that repeated WD-PR produces alterations in hypothalamic transcripts and also sensitizes sodium appetite in HTZ. They suggest an association between the components of hypothalamic RAS and the apelin system, with neural and behavioral plasticity produced by repeated episodes of WD-PR in a normotensive strain. The results also indicate that the inherited hyperactive brain RAS is not a guarantee for sensitization of sodium intake in the male adult SHR exposed to repeated WD-PR.

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