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T Tsuchihashi

Publications and source records attributed to T Tsuchihashi.

95 records · Page 6Linked to original sources
PubMedDate not supplied

Haemodynamic and humoral consequences of chronic infusion of vasopressin in conscious rats.

1. To determine the long-term haemodynamic and humoral effects of arginine vasopressin (AVP), a chronic intravenous infusion of AVP was performed in conscious Wistar normotensive rats. 2. AVP (1, 10, 50 or 100 ng/h) or saline as a vehicle control was infused continuously into the right jugular vein at a rate of 1 microL/h using an osmotic minipump for 7 days. 3. As a result, significant elevations of systolic blood pressure were observed in association with increases in plasma AVP concentration. Significant decreases in heart rate were observed during infusion of 100 ng/h of AVP. Mean arterial pressures measured directly on the sixth day of infusion were significantly higher in the rats given 50 ng/h (125 +/- 3 mmHg) or 100 ng/h (125 +/- 2 mmHg) compared with control rats (117 +/- 2 mmHg). Intravenous injection of the V1 antagonist, d(CH2)5Tyr(Me)AVP, significantly reduced the elevated mean arterial pressure induced by 50 or 100 ng/h of AVP (-7 +/- 4 and -11 +/- 2 mmHg, respectively). Plasma renin and norepinephrine concentrations were not affected by AVP infusion, while plasma epinephrine concentration was lower in the rats given 100 ng/h of AVP. Intravenous infusion of AVP did not alter bodyweight, serum electrolytes or osmolality. 4. These results suggest that AVP has a long-term pressor effect which is attributable to its vasoconstrictor action in conscious rats.

Animals↗
PubMedDate not supplied

Spontaneous fall in blood pressure and reactivity of sympathetic nervous system in hospitalized patients with essential hypertension.

We evaluated whether reduction in sympathetic reactivity plays a major role in the spontaneous falls in blood pressure (BP) experienced during hospitalization by patients with essential hypertension. In the present case BP fell on the 2nd day of hospitalization. The responses of plasma catecholamines (CA) and BP to both handgrip and tilting were not altered during either the first 24 hours or the entire 7 days of hospitalization. The effect of phentolamine on BP was similar on the 1st, 2nd and 7th days. However, the resting levels of plasma norepinephrine before handgrip, tilting and phentolamine were significantly diminished on the 7th day, but not on the 2nd day. In conclusion, the diminution of sympathetic activity may be partly responsible for the hospitalization-induced fall in BP in the late stages.

Adult↗
PubMedDate not supplied

Hypertension and dementia.

Vascular dementia (VD) is more prevalent than Alzheimer's disease (AD) in Japan, while AD is more common in Western countries. In the Hisayama study, a community-based cohort study of Japan, the prevalence of VD decreased in men during the 7-years (1985-1992) follow-up period, while the prevalence of AD remained unchanged both in men and women. The incidence of dementia increases with age, particularly AD aged 85 or older. Hypertension is a major risk factor for VD. Other risk factors include age, prior stroke, diabetes, alcohol intake, heart disease, and smoking. In contrast, age, a family history of dementia, a low educational level, and low physical activity are risk factors for AD. The role of hypertension in AD remains controversial; there has been positive, negative, or no association existed between blood pressure levels and AD. A recent clinical trial has disclosed the potential preventive effect of antihypertensive treatment on the incidence of dementia, especially of AD. Although the role of vascular factors for the pathogenesis of AD is becoming recognized, the effectiveness of antihypertensive treatment on the prevention of AD should be further clarified in the future studies.

Aged↗