A chromosome 1 blood pressure quantitative trait locus (QTL) was introgressed from the stroke-prone spontaneously hypertensive rats (SHRSP) to Wistar-Kyoto (WKY) rats. This congenic strain (WKYpch1.0) showed an exaggerated pressor response to both restraint and cold stress. In this study, we evaluated cardiovascular and sympathetic response to an air-jet stress and also examined the role of the brain renin-angiotensin system (RAS) in the stress response of WKYpch1.0. We measured mean arterial pressure (MAP), heart rate (HR), and renal sympathetic nerve activity (RSNA) responses to air-jet stress in WKYpch1.0, WKY, and SHRSP. We also examined effects of intracerebroventricular administration of candesartan, an ANG II type 1 receptor blocker, on MAP and HR responses to air-jet stress. Baseline MAP in the WKYpch1.0 and WKY rats were comparable, while it was lower than that in SHRSP rats. Baseline HR did not differ among the strains. In WKYpch1.0, air-jet stress caused greater increase in MAP and RSNA than in WKY. The increase in RSNA was as large as that in SHRSP, whereas the increase in MAP was smaller than in SHRSP. Intracerebroventricular injection of a nondepressor dose of candesartan inhibited the stress-induced pressor response to a greater extent in WKYpch1.0 than in WKY. Intravenous injection of phenylephrine caused a presser effect comparable between WKYpch1.0 and WKY. These results suggest that the chromosome 1 blood pressure QTL congenic rat has a sympathetic hyperreactivity to an air-jet stress, which causes exaggerated pressor responses. The exaggerated response is at least partly mediated by the brain RAS.
Thiazolidinediones, which stimulate peroxisome proliferator-activated receptor , have been shown to prevent cardiovascular injury. However, little is known about their effects on salt-sensitive hypertension. We thus investigated whether or not pioglitazone affects left ventricular (LV) hypertrophy in Dahl salt-sensitive rats, then compared its effects to those of an angiotensin II receptor blocker, candesartan. Rats were used at 16 weeks of age after they had been fed either a low-salt (0.3%; DSL) or high-salt (8%; DSH) diet for 10 weeks; some of the DSH rats were treated with pioglitazone (10 mg/kg/day) or candesartan (4 mg/kg/day).Both drugs decreased the elevated blood pressure in DSH rats, although it was still higher than in DSL rats.
Azelnidipine is a new dihydropyridine calcium channel blocker that causes minimal stimulation of the sympathetic nervous system despite its significant depressor effect. In the present study, we examined the effects of oral or intravenous administration of azelnidipine on cardiovascular and renal sympathetic nerve
Objective: We investigated the relationship between the pattern of hypertension and nocturia. Methods: Seventy-seven patients who were being treated for hypertension completed a questionnaire regarding the number of times they urinated during the day and at night, and measured their blood pressure at home immediately after rising in the morning and just before going to sleep at night. The patients' blood pressure was also measured at the clinic. The patients were divided into groups according to their blood pressure patterns. The relationship between blood pressure pattern and number of urinations during the day and at night was investigated. Results: When the patients were divided into white coat hypertension, masked hypertension, sustained hypertension, and normotension groups, the number of daytime urinations was significantly lower in the sustained hypertension group compared with the normotension and white coat hypertension groups. When the subjects were divided into morning blood pressure surge and non-morning surge groups or into morning hypertension and non-morning hypertension groups, the numbers of nighttime urinations was significantly higher in the morning surge group or the morning hypertension group compared with the non-morning surge group or non-morning hypertension group, respectively. Conclusion: Sustained hypertension and elevation of blood pressure in the early morning influence the frequency of daytime and nighttime urination, respectively. It is important to control both the blood pressure and nocturia of hypertensive patients to improve their prognosis.
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