Vasomotion: Mechanisms and Physiological Importance

Nilsson, Holger; Aalkjær, Christian

doi:10.1124/mi.3.2.79

Cited by 292 publications

(262 citation statements)

References 86 publications

Supporting

Mentioning

254

Contrasting

Unclassified

Order By: Relevance

“…Interestingly, the period of the oscillations is similar to the 10-s period of the spontaneous background vasomotion observed in the brain and other organs (Mayhew et al, 1996;Mitra et al, 1997;Nilsson and Aalkjaer, 2003;Obrig et al, 2000). The background oscillations are enhanced by reduced perfusion (Nilsson and Aalkjaer, 2003) and decreased by elevated perfusion (Obrig et al, 2000). This dependence on the baseline CBF is similar to what we observe for the stimulus-induced oscillations and suggests a possible shared mechanism for both types of oscillations.…”

Section: Changes In Bold Dynamicssupporting

confidence: 72%

“…For example, the hyperoxic visual BOLD response shown in Kashikura et al (2001) shows a hint of an oscillation with a period of 7 s but is not discussed in the text. Interestingly, the period of the oscillations is similar to the 10-s period of the spontaneous background vasomotion observed in the brain and other organs (Mayhew et al, 1996;Mitra et al, 1997;Nilsson and Aalkjaer, 2003;Obrig et al, 2000). The background oscillations are enhanced by reduced perfusion (Nilsson and Aalkjaer, 2003) and decreased by elevated perfusion (Obrig et al, 2000).…”

Section: Changes In Bold Dynamicsmentioning

confidence: 48%

See 1 more Smart Citation

Caffeine alters the temporal dynamics of the visual BOLD response

et al. 2004

View full text Add to dashboard Cite

The blood oxygenation level-dependent (BOLD) responses to visual stimuli, using both a 1-s long single trial stimulus and a 20-s long block stimulus, were measured in a 4-T magnetic field both before and immediately after a 200-mg caffeine dose. In addition, resting levels of cerebral blood flow (CBF) were measured using arterial spin labeling. For the single trial stimulus, the caffeine dose significantly ( p b 0.05) reduced the time to peak (TTP), the time after the peak at which the response returned to 50% of the peak amplitude (TA 50 ), and the amplitude of the poststimulus undershoot in all subjects (N = 5). Other parameters, such as the full-width half-maximum (FWHM) and the peak amplitude, also showed significant changes in the majority of subjects. For the block stimulus, the TTP, TA 50 , and the time for the response to reach 50% of the peak amplitude (T 50 ) were significantly reduced. In some subjects, oscillations were observed in the poststimulus portion of the response with median peak periods of 9.1 and 9.5 s for the single trial and block responses, respectively. Resting CBF was reduced by an average of 24%. The reproducibility of the results was verified in one subject who was scanned on 3 different days. The dynamic changes are similar to those previously reported for baseline CBF reductions induced by hypocapnia and hyperoxia. D

show abstract

Section: Changes In Bold Dynamicssupporting

confidence: 72%

Section: Changes In Bold Dynamicsmentioning

confidence: 48%

Caffeine alters the temporal dynamics of the visual BOLD response

et al. 2004

View full text Add to dashboard Cite

show abstract

“…Disentangling all of the different effects that occur under conditions of reduced perfusion is thus a substantial task, especially when attempting to interpret experimental data. This complexity is undoubtedly one of the key reasons why "the conclusions borne from theoretical studies have received little direct support from experiments", Nilsson and Aalkjaer, 2003. The model that we present here thus attempts to shed additional insight onto this process by considering a previously neglected component, i.e.…”

Section: Accepted Manuscriptmentioning

confidence: 99%

“…Although it has been seen in many studies over many years, the physiological consequences of vasomotion remain very unclear, Nilsson and Aalkjaer, 2003. One potential benefit is that the time-averaged hydraulic resistance to flow is lower than the steady state resistance, due to the non-linear relationship between vessel radius and resistance, Meyer et al, 2002.…”

Section: Introductionmentioning

confidence: 99%

Quantification of the effects of vasomotion on mass transport to tissue from axisymmetric blood vessels

Hapuarachchi

Park

Payne

2010

Journal of Theoretical Biology

View full text Add to dashboard Cite

International audienceThe process known as vasomotion, rhythmic oscillations in vessel diameter, has been proposed to act as a protective mechanism for tissue under conditions of reduced perfusion, since it is frequently only observed experimentally when perfusion levels are reduced. This could be due to a resultant increase in oxygen transport from the vasculature to the surrounding tissue, either directly or indirectly. It is thus potentially of significant clinical interest as a warning signal for ischemia. However, there has been little analysis performed to quantify the effects of vessel wall movement on time-averaged mass transport. We thus present a detailed analysis of such mass transport for an axisymmetric vessel with a periodically oscillating wall, by solving the non-linear mass transport equation, and quantify the differences between the time-averaged mass transport under conditions of no oscillation (i.e. the steady-state) and varying wall oscillation amplitude. The results show that if the vessel wall alone is oscillated, with an invariant wall concentration, the time-averaged mass transport is reduced relative to the steady-state, but if the vessel wall concentration is also oscillated, then mass transport is increased, although this is generally only true when these oscillate in phase with each other. The influence of Péclet number and the non-dimensional rate of consumption of oxygen in tissue, as well as the amplitude of oscillations, are fully characterised. We conclude by considering the likely implications of these results in the context of oxygen transport to tissue

show abstract

“…While it has been suggested that oscillation in vascular tone can promote oxygen delivery, the exact physiological role of this extensively studied phenomenon remains to be elucidated (Nilsson and Aalkjaer, 2003;Aalkjaer and Correspondence to: Reza Tabrizchi, Ph.D. and Professor, Division of BioMedical Sciences, Faculty of Medicine, Health Sciences Centre, Memorial University, St. John's, NL, A1B 3V6, Canada Phone: +1-709-777-6864 Fax: +1-709-777-7010 e-mail: rtabrizc@mun.ca Nilsson, 2005). Vasomotor oscillations are known to occur at different frequencies comprising "slow waves" at 1-3 cycles per minute (Seifert et al, 1988;Kastrup et al, 1989;Bollinger et al, 1991) and "fast waves" at 10-25 cycles per minute (Colantuoni et al, 1985;Meyer et al, 1987;Slaaf et al, 1987;Kastrup et al, 1989).…”

Section: Introductionmentioning

confidence: 99%

Potassium-induced intermittent vasomotion in rat isolated pulmonary artery

Bieger

Ford

Tabrizchi

2011

J. Smooth Muscle Res.

View full text Add to dashboard Cite

A novel intermittent vasomotion induced by potassium in rat pulmonary artery was investigated with a view to characterize the ion channel mechanisms governing such secondary oscillatory activity. Isometric force was recorded from ring preparations of rat isolated pulmonary arteries incubated in a modified Krebs buffer containing K ]e. Our findings support the concept that a secondary vasomotive oscillator operates in rat pulmonary artery which enables the activity of the primary oscillator to be regulated in a cyclic manner via sarcolemmal L-type Ca 2+ channels and an array of K conductances.

show abstract

Vasomotion: Mechanisms and Physiological Importance

Cited by 292 publications

References 86 publications

Caffeine alters the temporal dynamics of the visual BOLD response

Caffeine alters the temporal dynamics of the visual BOLD response

Quantification of the effects of vasomotion on mass transport to tissue from axisymmetric blood vessels

Potassium-induced intermittent vasomotion in rat isolated pulmonary artery

Contact Info

Product

Resources

About