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.