Blood pressures, heart rate and locomotor activity during salt loading and angiotensin II infusion in protease-activated receptor 2 PAR2 knockout miceReport as inadecuate




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BMC Physiology

, 8:20

First Online: 21 October 2008Received: 01 August 2008Accepted: 21 October 2008

Abstract

BackgroundIn this study we used radiotelemetry to measure hemodynamic variables and locomotor activity in conscious unrestrained male Protease-Activated Receptor 2 PAR-2 knockout mice in order to provide a detailed assessment of their blood pressure phenotype. In addition we tested for an influence of PAR-2 on salt-sensitivity 8% versus 0.5% NaCl diet, 2.5 weeks and angiotensin II-induced hypertension 1 μg Ile-angiotensin II-kg-min versus 0.25 μl-h saline, 2 weeks.

ResultsSystolic arterial pressures of PAR-2 - 129 ± 1 mmHg, n = 21, P < 0.05 were statistically higher than those of C57BL-6J 124 ± 1 mmHg, n = 33 throughout the 24 h period under baseline conditions. Pulse pressures in PAR-2 - were also significantly elevated 33 ± 1 mmHg versus 30 ± 1 mmHg, P < 0.05, whereas diastolic arterial pressures were not. Heart rates in PAR-2 - were not significantly different than controls, with the exception that heart rate of PAR-2 - was 23 beats per min higher than controls P < 0.001 during periods of nocturnal activity. The diurnal pattern and intensity of locomotor activity were not found to differ between strains. A high salt diet led to increased blood pressures, decreased heart rates, increased time spent active and decreased intensity levels of locomotor activity. Salt-induced changes in systolic and pulse pressures in PAR-2 - were less than in C57B-6J. Angiotensin II treatment increased pressures, decreased heart rates, decreased time spent active and decreased intensity levels of activity of PAR-2 -, all to the same extent as C57BL-6J. A trend of lower blood pressures during the middle period of angiotensin II treatment period was observed in individual PAR-2 -.

ConclusionThe data indicated gene knockout of PAR-2 was associated with a modest change in blood pressure phenotype. PAR-2 - mice exhibited moderate elevation of systolic arterial and pulse pressures, yet no increased diastolic arterial pressure, no increased blood pressure responses to high salt diet and a subtle difference in the time course of the blood pressure responses to angiotensin II infusion.

Electronic supplementary materialThe online version of this article doi:10.1186-1472-6793-8-20 contains supplementary material, which is available to authorized users.

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Author: John J McGuire - Bruce N Van Vliet - Sarah J Halfyard

Source: https://link.springer.com/







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