Brain metabolism and blood flow during sleep

Abstract

sleep/wake cycle, as sleep stages often alternate with a On the other hand, however, many problems concerning shorter time constant, with DS, in particular, normally not cerebral blood flow and metabolism remain to be solved lasting that long. A common strategy in most sleep studies (e.g. the regulation of blood flow, the nature of the has been, therefore, to correlate glucose utilization during flow-metabolism coupling, the existence of capillary measurement with the time spent in different sleep/wake recruitment, and the extent of non-oxidative metabolism).states (weighted for variations in glucose plasma concentraSleep is a natural, stereotyped, repetitive phenomenon, tion (in animals) and positron emission tomography (in humans) model with which to address these specific problems, while are hereafter considered separately, the same common logic findings about brain circulation and metabolism during sleep applies and their results are, in principle, comparable. will foster our understanding of brain circulation and metabolism in general.(a) Autoradiography studies Rat: Ramm and Frost (1983) found no correlation between this reason experimental data in this field have been tightly graphy), and (ii) C E R E B R A L E N E R G Y METABOLISM Direct measurements2.1.1 Local cerebral glucose utilization. When Greenberg wrote his review in 1980, very few attempts had been made to measure directly cerebral metabolism during sleep (Mangold et al. 1955;Meyer and Toyoda 1971) and, due to limitations in methodology, none could address the issue of regional differences in metabolic activity. The rather long list of papers considered in this section bears witness to the mean cerebral glucose utilization (reflected by mean optical density in the autoradiographs) and the different sleep/wake states. They also considered the "relative metabolic activity", which was calculated as the regional optic density given as a proportion of the mean brain optic density; this expresses the level of metabolic activity in a region relative to the mean level in the brain. During SS, relative metabolic activity decreases in the cerebellum, in most thalamic nuclei and in cortical layer IV, and increases in some hippocampal and hypothalamic structures. DS is associated with a relative decrease in metabolic activity in the cerebellum, and a relative increase in some brainstem regions (e.g. pontine Pavlides et al. (1987) reported a decreased cerebral glucose Correspondence: Institute Fisiologia Umana, Porta S. Donato 2, raphe, gigantocellular tegmental field, substantia nigra).

The relation of intracranial pressure B-waves to different sleep stages in patients with suspected normal pressure hydrocephalus

“…Cerebral blood flow, cerebral glucose metabolism and the average cerebral metabolic rate based on oxygen uptake are reduced in synchronized sleep, while they increase during REM sleep [14,20,24,26,42,46]. Furthermore, it has been demonstrated by MR with interleaved gradient-echo pulse sequences that the net flow of CSF through tile cerebral aqueduct is higher at night in normal volunteers [33].…”

Neuron–glia metabolic coupling and plasticity

“…This long-term plastic response triggers the induction of expression of a coordinated set of genes involved in glycogen resynthesis such as the transcription factors C/EBP, and the genes encoding for the enzymes glycogen synthase and protein targeting to glycogen. mouse, rat and cat with the [ 14 C]2-deoxyglucose technique, have reported that energy metabolism exhibits a decrease during slow-wave sleep (SWS) and an increase during paradoxical sleep (PS), depending on the brain areas (for a review, see Franzini, 1992). It has also been reported that the synthesis of glycogen is increased during SWS with a 50-70% rise when compared to the preceding waking period (Karnovsky et al, 1983).…”

Positron Emission Tomography with Deoxyglucose-F18 Imaging of Sleep

“…Most studies indicate that rates of global cerebral metabolism rate and cerebral blood flow (CBF) are similar during REM sleep and wakefulness (Buchsbaum et al 1989;Braun et al 1998;Franzini 1992;Kuboyama et al 1997;Lydic et al 1991;Madsen et al 1991;Madsen 1993;Maquet et al 1996). Nevertheless, the specific patterns of metabolic activity throughout the brain show distinctive regional differences between REM and waking conditions.…”