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Hypothalamic Angiotensin Type 1 Receptors and Sodium Chloride Intake in Genetically Hypertensive Rats Raised on High Salt Diets
Author(s) -
Bradshaw Timothy,
Osborn Jeffrey L
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.24.1_supplement.lb718
Subject(s) - endocrinology , medicine , captopril , angiotensin ii , sodium , chemistry , angiotensin ii receptor type 1 , offspring , saline , distilled water , renin–angiotensin system , weaning , receptor , blood pressure , biology , pregnancy , organic chemistry , chromatography , genetics
Spontaneously Hypertensive Rats (SHR) may have impaired titration of ingested sodium chloride. The role of Angiotensin II (AII) and hypothalamic angiotensin (AT1) receptor expression in regulating salt and water intake was evaluated in SHR raised from weaning on high salt. Female SHR were crossed with normotensive, Brown Norway (BN) males and hypertensive offspring then were sib/sib mated yielding hypertensive F2 rats that were raised to adulthood on either 4.0% (HS; n=7) or 0.8% (NS; n=8) NaCl chow. NS and HS rats were placed in metabolic pens and offered ad lib access to 2% saline, distilled H2O and sodium free chow and daily water and sodium intakes were measured. After control (2 days), AII synthesis was blocked with Captopril (1 g/L) in the saline and H2O (5 days). Blockade of AII increased NaCl ingestion in both NS (2.63 + 1.57 to 5.20 + 1.66 mmol/day) and HS (3.90 + 1.88 to 7.65 + 3.29 mmol/day) rats compared to control. Captopril decreased H2O ingested by HS rats (20.47 + 3.95 ml/day to 8.29 + 2.78 ml/day) but not by NS rats (16.39 + 4.86 ml/day vs.15.09 + 4.19 ml/day). Hypothalamic AT1 receptor density (western blot) was 60% lower in HS rats compared to NS rats (p<0.05). Thus, reduced AT1 receptor expression in SHR raised on high salt intake may limit HS rats from appropriately adjusting water intake during elevated salt intake. (Funded by NSF #0437768)