| Abstrakt: |
In previous studies we demonstrated that myogenic vascular function specifically affects very low frequency (VLF, 0.02-0.2 Hz) blood pressure variability (BPV) in rats. In addition, impaired cerebrovascular myogenic function has been associated with hemorrhagic stroke in stroke-prone spontaneously hypertensive rats (SHR-SP) on high-salt diet. Therefore, we hypothesized that VLF BPV is reduced in SHR-SP on high-salt diet but not in stroke-resistant spontaneously hypertensive rats (SHR-SR) or normotensive Wistar Kyoto rats (NT-WKY). NT-WKY (n=9), SHR-SR (n=14), and SHR-SP (n=13) received a high-salt diet (1% NaCl in drinking water) for 4 or 6 weeks before arterial blood pressure was recorded in conscious animals. Blood pressure values at the 4th and 6th week of high-salt diet were greater in SHR-SP than in SHR-SR and greater in SHR-SR than in NT-WKY. From the 4th to the 6th week of high-salt diet, VLF BPV tended to increase in NT-WKY (from 9.1±2.2 mmHg² to 13.5±6.4 mmHg², not sig.) and SHR-SR (from 14.6±1.4 mmHg² to 21.6±2.0 mmHg², not sig.). In contrast, VLF BPV significantly decreased during this time period in SHR-SP (from 20.2±2.8 mmHg² to 11.8±3.8 mmHg², p<0.05). These data suggest that reduced VLF BPV indicates impaired myogenic vascular function in SHR-SP on high-salt diet prior to hemorrhagic stroke. [ABSTRACT FROM AUTHOR] |
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