scholarly journals Functional Role of Diverse Changes in Sympathetic Nerve Activity in Regulating Arterial Pressure during REM Sleep

SLEEP ◽  
2011 ◽  
Vol 34 (8) ◽  
pp. 1093-1101 ◽  
Author(s):  
Misa Yoshimoto ◽  
Ikue Yoshida ◽  
Kenju Miki
2009 ◽  
Vol 106 (4) ◽  
pp. 1050-1056 ◽  
Author(s):  
Priscila A. Cassaglia ◽  
Robert I. Griffiths ◽  
Adrian M. Walker

Sympathetic nerve activity (SNA) in neurons projecting to skeletal muscle blood vessels increases during rapid-eye-movement (REM) sleep, substantially exceeding SNA of non-REM (NREM) sleep and quiet wakefulness (QW). Similar SNA increases to cerebral blood vessels may regulate the cerebral circulation in REM sleep, but this is unknown. We hypothesized that cerebral SNA increases during phasic REM sleep, constricting cerebral vessels as a protective mechanism against cerebral hyperperfusion during the large arterial pressure surges that characterize this sleep state. We tested this hypothesis using a newly developed model to continuously record SNA in the superior cervical ganglion (SCG) before, during, and after arterial pressure surges occurring during REM in spontaneously sleeping lambs. Arterial pressure (AP), intracranial pressure (ICP), cerebral blood flow (CBF), cerebral vascular resistance [CVR = (AP − ICP)/CBF], and SNA from the SCG were recorded in lambs ( n = 5) undergoing spontaneous sleep-wake cycles. In REM sleep, CBF was greatest (REM > QW = NREM, P < 0.05) and CVR was least (REM < QW = NREM, P < 0.05). SNA in the SCG did not change from QW to NREM sleep but increased during tonic REM sleep, with a further increase during phasic REM sleep (phasic REM > tonic REM > QW = NREM, P < 0.05). Coherent averaging revealed that SNA increases preceded AP surges in phasic REM sleep by 12 s ( P < 0.05). We report the first recordings of cerebral SNA during natural sleep-wake cycles. SNA increases markedly during tonic REM sleep, and further in phasic REM sleep. As SNA increases precede AP surges, they may serve to protect the brain against potentially damaging intravascular pressure changes or hyperperfusion in REM sleep.


2003 ◽  
Vol 284 (2) ◽  
pp. R467-R473 ◽  
Author(s):  
Kenju Miki ◽  
Makiko Kato ◽  
Suzuko Kajii

The relationship between renal sympathetic nerve activity (RSNA) and systemic arterial pressure obtained during rapid eye movement (REM) sleep was compared with that obtained in other sleep and awake states. Electrodes for the measurements of RSNA, electrocardiogram, electromyogram, and electroencephalogram and a catheter for the measurement of systemic arterial pressure were implanted while the animals were under aseptic conditions at least 5 days before the experiment. During the transition from non-REM (NREM) to REM sleep, RSNA and heart rate (HR) decreased immediately by 46 ± 2% ( P < 0.05) and 22 ± 3 beats/min ( P < 0.05), respectively, over 3 s after the onset of REM sleep. Meanwhile, systemic arterial pressure increased gradually after the onset of REM sleep, which was apparently independent of the changes in RSNA. During REM sleep, the relationships between RSNA/HR and systemic arterial pressure were dissociated compared with that obtained during the other behavioral states. These data indicate that the interdependency between systemic arterial pressure and RSNA during REM sleep is likely to be modified compared with other behavioral states.


1999 ◽  
Vol 276 (6) ◽  
pp. R1579-R1586 ◽  
Author(s):  
Karie E. Scrogin ◽  
Eugene T. Grygielko ◽  
Virginia L. Brooks

Acute infusion of hypertonic fluid increases mean arterial pressure (MAP) in part by elevating nonrenal sympathetic activity. However, it is not known whether chronic, physiological increases in osmolality also increase sympathetic activity. To test this hypothesis, MAP, heart rate (HR), and lumbar sympathetic nerve activity (LSNA) were measured in conscious, 48-h water-deprived rats (WD) during a progressive reduction in osmolality produced by a 2-h systemic infusion (0.12 ml/min) of 5% dextrose in water (5DW). Water deprivation significantly increased osmolality (308 ± 2 vs. 290 ± 2 mosmol/kgH2O, P < 0.001), HR (453 ± 7 vs. 421 ± 10 beats/min, P < 0.05), and LSNA (63.5 ± 1.8 vs. 51.9 ± 3.8% baroreflex maximum, P < 0.01). Two hours of 5DW infusion reduced osmolality (−15 ± 5 mosmol/kgH2O), LSNA (−23 ± 3% baseline), and MAP (−10 ± 1 mmHg). To evaluate the role of vasopressin in these changes, rats were pretreated with a V1-vasopressin receptor antagonist. The antagonist lowered MAP (−5 ± 1 mmHg) and elevated HR (32 ± 7 beats/min) and LSNA (11 ± 3% baseline) in WD ( P < 0.05), but not in water-replete, rats. 5DW infusion had a similar cumulative effect on all variables in V1-blocked WD rats, but had no effect in water-replete rats. Infusion of the same volume of normal saline in WD rats did not change osmolality, LSNA or MAP. Together these data indicate that, in dehydrated rats, vasopressin supports MAP and suppresses LSNA and HR and that physiological changes in osmolality directly influence sympathetic activity and blood pressure independently of changes in vasopressin and blood volume.


2003 ◽  
Vol 285 (4) ◽  
pp. R834-R841 ◽  
Author(s):  
Claude Julien ◽  
Bruno Chapuis ◽  
Yong Cheng ◽  
Christian Barrès

The role of arterial baroreceptors in controlling arterial pressure (AP) variability through changes in sympathetic nerve activity was examined in conscious rats. AP and renal sympathetic nerve activity (RSNA) were measured continuously during 1-h periods in freely behaving rats that had been subjected to sinoaortic baroreceptor denervation (SAD) or a sham operation 2 wk before study ( n = 10 in each group). Fast Fourier transform analysis revealed that chronic SAD did not alter high-frequency (0.75-5 Hz) respiratory-related oscillations of mean AP (MAP) and RSNA, decreased by ∼50% spectral power of both variables in the midfrequency band (MF, 0.27-0.74 Hz) containing the so-called Mayer waves, and induced an eightfold increase in MAP power without altering RSNA power in the low-frequency band (0.005-0.27 Hz). In both groups of rats, coherence between RSNA and MAP was maximal in the MF band and was usually weak at lower frequencies. In SAD rats, the transfer function from RSNA to MAP showed the characteristics of a second-order low-pass filter containing a fixed time delay (∼0.5 s). These results indicate that arterial baroreceptors are not involved in production of respiratory-related oscillations of RSNA but play a major role in the genesis of synchronous oscillations of MAP and RSNA at the frequency of Mayer waves. The weak coupling between slow fluctuations of RSNA and MAP in sham-operated and SAD rats points to the interference of noise sources unrelated to RSNA affecting MAP and of noise sources unrelated to MAP affecting RSNA.


Hypertension ◽  
2001 ◽  
Vol 38 (3) ◽  
pp. 384-388 ◽  
Author(s):  
Marcelo L.G. Correia ◽  
Donald A. Morgan ◽  
Jennifer L. Mitchell ◽  
William I. Sivitz ◽  
Allyn L. Mark ◽  
...  

2005 ◽  
Vol 288 (4) ◽  
pp. R837-R845 ◽  
Author(s):  
Carolyn J. Barrett ◽  
Simon C. Malpas

While there is no disputing the critical role of baroreflexes in buffering rapid changes in arterial pressure, their role in long-term pressure control has become an area of controversy. Recent experiments using novel techniques have challenged the traditional view that arterial baroreflexes are not involved in setting chronic arterial pressure levels. Resetting of the arterial baroreflex, often used as an argument against the arterial baroreflex playing a role in long-term pressure control is rarely complete. The arterial baroreflex is just one of the many neural, hormonal, and intrinsic mechanisms involved in arterial pressure control and while the removal of the arterial baroreflex alone has little effect on mean arterial pressure it is too simplistic to suggest that the baroreflex has no role in long-term pressure control. Renal sympathetic nerve activity appears to be particularly resistant to resetting in response to ANG II-induced hypertension. Given the important role of the kidneys in long-term pressure control, we suggest there is a clear need to develop experimental techniques whereby sympathetic nerve activity to the kidneys and other organs can be monitored over periods of weeks to months.


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