Sympathetic neural responses to increased osmolality in humans.
نویسندگان
چکیده
The purpose of this study was to examine the relationship between osmolality and efferent sympathetic outflow in humans. We hypothesized that increased plasma osmolality would be associated with increases in directly measured sympathetic outflow. Muscle sympathetic outflow was successfully recorded in eight healthy subjects during a 60-min intravenous hypertonic saline infusion (HSI; 3% NaCl) on one day and during a 60-min intravenous isotonic saline (ISO) infusion (0.9% NaCl) on a different day. The HSI provides an osmotic and volume stimulus, whereas the ISO infusion provides a volume-only stimulus. Muscle sympathetic nerve activity was quantified using the technique of peroneal microneurography. Plasma osmolality increased during the HSI but not during the ISO infusion (ANOVA, P < 0.05). Sympathetic outflow differed between the trials (ANOVA, P < 0.05); during the HSI burst, frequency initially increased from 14.6 +/- 2.5 to 18.1 +/- 1.9 bursts/min; during the ISO infusion, burst frequency initially declined from 14.7 +/- 2.5 to 12.0 +/- 2.1 bursts/min. Plasma norepinephrine concentration was greater at the end of the HSI compared with the end of the ISO infusion (HSI: 297 +/- 64 vs. ISO: 202 +/- 49 pg/ml; ANOVA, P < 0.05). We conclude that HSI-induced increases in plasma osmolality are associated with increases in sympathetic activity in humans.
منابع مشابه
Influence of increased plasma osmolality on sympathetic outflow during apnea.
Animal models have shown that peripheral chemoreceptors alter their firing patterns in response to changes in plasma osmolality, which, in turn, may modulate sympathetic outflow. The purpose of this study was to test the hypothesis that increases in plasma osmolality augment muscle sympathetic nerve activity (MSNA) responses to chemoreceptor activation. MSNA was recorded from the peroneal nerve...
متن کاملGlutamatergic input in the PVN is important in renal nerve response to elevations in osmolality.
Elevations in plasma osmolality elicit reflex humoral and neural responses. The hypothalamic paraventricular nucleus (PVN) is important in humoral responses. We have investigated whether the PVN contributed to the renal nerve reduction that is normally elicited by increased plasma osmolality in the conscious rabbit. Renal sympathetic nerve activity (RSNA) was monitored after an intravenous infu...
متن کاملInteractions of plasma osmolality with arterial and central venous pressures in control of sympathetic activity and heart rate in humans.
Plasma osmolality alters control of sympathetic activity and heart rate in animal models; however, it is unknown whether physiological increases in plasma osmolality have such influences in humans and what effect concurrent changes in central venous and/or arterial pressures may have. We tested whether physiological increases in plasma osmolality (similar to those during exercise dehydration) a...
متن کاملPositional Relationship between Natural Killer Cells and Distribution of Sympathetic Nerves in Decidualized Mouse Uterus
Background: Uterine natural killer (uNK) cells are the most abundant leukocytes in pre-implantation endometrium and early pregnancy deciduas in humans and rodents. They are associated with structural changes in maternal spiral arteries but regulation of their re-cruitment and activation is incompletely understood. The major subpopulation of uNK cells in humans expresses CD56, the neural cell ad...
متن کاملDynamic cardiovascular responses to infusions of atrial natriuretic factor in humans.
We sought to demonstrate a hypotensive effect from infusions of atrial natriuretic factor (ANF) into humans and to describe the mechanism(s) of this effect. Cardiovascular and hormonal responses to human ANF-(99-126) (125 ng/kg bolus followed by a 30-minute infusion at 25 ng/kg/min) were determined in eight conscious volunteers and compared with responses of eight time-control subjects who rece...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
- American journal of physiology. Heart and circulatory physiology
دوره 291 5 شماره
صفحات -
تاریخ انتشار 2006