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Elevated Arterial Pressure in Conscious Water Deprived Rats: Role of Global and Regional Sympathetic Activity
Author(s) -
Veitenheimer Britta,
Osborn John
Publication year - 2012
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.26.1_supplement.1104.5
Subject(s) - splanchnic , mean arterial pressure , splanchnic nerves , blood pressure , medicine , atenolol , heart rate , denervation , baroreflex , anesthesia , lumbar , endocrinology , hemodynamics , stimulation , surgery
Mean arterial pressure (MAP) and plasma osmolality (Posm) are elevated during water deprivation (WD) in conscious rats. Studies in anesthetized rats suggest that elevated MAP during WD is due to osmotically driven increases in lumbar sympathetic nerve activity (SNA); however, renal and splanchnic SNA may also play a role. We investigated the role of global and regional SNA in elevating MAP during 48 hours of WD in conscious rats. MAP and heart rate (HR) were measured by telemetry before and during 48hr of WD. Global sympathetic blockade was achieved by chronic administration of the α 1 and β 1 adrenoceptor antagonists terazosin and atenolol, respectively. MAP was increased in vehicle treated rats (16±1 mmHg) at 48 hours of WD compared to baseline. This increase in MAP was significantly less in α1/β1 blocked rats (1±2 mmHg) despite similar changes in Posm and HR. In additional experiments, selective denervation of the splanchnic or renal vascular beds had no effect on the MAP response to 48 hr WD. We are currently investigating the contribution of the lumbar nerves and adrenal responses to increased MAP in WD. These data support the hypothesis that elevated MAP during 48 hours of WD is sympathetically mediated. However, neither splanchnic nor renal nerves are necessary for the MAP response to WD. Supported by HLR0164176.