Circadian Variation of Plasma Catecholamines in Young and Old Men: Relation to Rapid Eye Movement and Slow Wave Sleep*

Abstract

Young and old healthy subjects with indwelling venous cannulae were found to undergo significant diurnal variations in plasma catecholamine levels. Both norepinephrine and epinephrine levels peaked in late morning and reached lowest values at night during sleep. Catecholamine levels were similar during slow wave and rapid eye movement sleep. While epinephrine levels were unaffected by age, norepinephrine levels were greater in older subjects by 28% during the day (at 1100 h; P less than 0.01) and by 75% at night (between 2200--0900 h; P less than 0.01). Older subjects slept less well; they had 90% less stage 4 sleep, 27% less rapid eye movement sleep, and twice as much wakefulness at night (P less than 0.05). These findings raise the possibility that this well known age effect on sleep may be related to increased sympathetic nervous system activity.

Dissociation of 24-hour catecholamine levels from blood pressure in older men.

“…Indeed, impaired sleep quality in the elderly has been shown to be associated with enhanced sympathetic activity. 42 However, comparison of sleep parameters of the two groups failed to disclose any differences in the duration and quality of sleep or in the relative distribution of the various sleep stages. Also, several lines of evidence suggest that the sleep apnea syndrome may be related to elevated arterial pressure.…”

Autonomic regulation of hematopoiesis and cancer

“…In humans, the major post-synaptic neurotransmitters of the SNS also show circadian levels in plasma and urine. [21][22][23] Since the SNS relays circadian signals to peripheral organs and participates in G-CSF-induced HSC mobilization, we studied the role of the SNS in circadian HSC traffic. A model was proposed where light-entrained circadian information is transmitted from the central pacemaker to the BM through the SNS, that releases noradrenaline rhythmically in the BM microenvironment, activating β 3 -adrenergic receptors expressed in stromal cells different from the osteoblast and triggering cyclic Cxcl12 downregulation and rhythmic HSC release to the bloodstream.…”

Circadian rhythms in myocardial metabolism and contractile function: influence of workload and oleate

“…Heart rate, blood pressure, cardiac output, platelet aggregability, myocardial infarction, arrhythmias, and sudden cardiac death all exhibit marked circadian rhythmicities in both humans and animal models (3,7,12,18,23,33). To date, these observations have been attributed primarily to diurnal variations in multiple extracellular stimuli (i.e., neurohumoral factors) such as autonomic and sympathetic activity (23,24,32). However, it is becoming increasingly clear that the intrinsic properties of cardiovascular components change over the course of the day, suggesting that oscillations in responsiveness to extracellular stimuli may contribute toward circadian rhythmicities in cardiovascular events (36, 37).…”