Autoregulation of blood flow.

Johnson, Paul C.

doi:10.1161/01.res.59.5.483

Cited by 359 publications

(205 citation statements)

References 126 publications

Supporting

Mentioning

190

Contrasting

Unclassified

Order By: Relevance

“…The metabolic regulation of vascular tone mediated by changes in oxygen or carbon dioxide tension has been much debated [8]. In the brain, elevating the oxygen level typically causes vasoconstriction of cerebral arterioles and results in a reduction of blood flow [9].…”

Section: Discussionmentioning

confidence: 99%

Effect of Carbogen, Oxygen and Intraocular Pressure on Heidelberg Retina Flowmeter Parameter ‘Flow’ Measured at the Papilla

Lietz¹,

Hendrickson²,

Orgül³

et al. 1998

Ophthalmologica

View full text Add to dashboard Cite

The aim of the study was to evaluate whether the Heidelberg retina flowmeter (HRF), a new device for retinal and anterior optic nerve blood flow assessment, can gauge, at least semiquantitatively, a known effect such as an increase in optic nerve blood flow by hypercapnia or a decrease in optic nerve blood flow by hyperoxia or high intraocular pressure (IOP). Measurements with the HRF were obtained at the papilla of three groups of 5 young healthy subjects (1) at baseline and after breathing 5% carbogen, (2) at baseline and after breathing 100% oxygen and (3) at baseline and after increasing IOP to 20 and 50 mm Hg. The changes in the value of the HRF parameter ‘flow’ were analyzed by means of a paired Student’s t test. Breathing 100% oxygen for 7 min resulted in a statistically significant decrease of 34.7±2.5% (mean ± SEM) in HR parameter ‘flow’ (p < 0.01) at the papilla. Breathing 5% carbogen for 7 min resulted in a statistically significant increase of 18.3±2.6% in HRF parameter ‘flow’ (p = 0.024). Increasing IOP to 20 mm Hg did not result in a statistically significant change in HRF parameter ‘flow’ (–9.6±7.4%; p = 0.13). Increasing IOP from 20 to 50 mm Hg, however, resulted in a statistically significant decrease of 40.1±6.6% in HRF parameter ‘flow’ (p = 0.003). With the applied stimuli, the HRF parameter ‘flow’ changed in the expected direction, i.e. an increase with hypercapnia and a decrease with hyperoxia or high IOP. The simplicity of use of the HRF instrument suggests that it might be well suited for a non-invasive, at least semiquantitative, assessment of changes in blood flow at the papilla.

show abstract

Section: Discussionmentioning

confidence: 99%

Effect of Carbogen, Oxygen and Intraocular Pressure on Heidelberg Retina Flowmeter Parameter ‘Flow’ Measured at the Papilla

Lietz¹,

Hendrickson²,

Orgül³

et al. 1998

Ophthalmologica

View full text Add to dashboard Cite

show abstract

“…It might be argued that the effect of LNMMA was also contingent, in part, on the generalized increase in vascular tone that this agent induced, inasmuc h as the interaction between flow and pressure can be dependent on the basal tone of the vessel (11). This potential confoundin g variable was clarified by the phenylephrine studies.…”

Section: Discussionmentioning

confidence: 99%

Flow-Induced Dilation in Newborn Intestine

Nowicki¹,

Miller²

1995

Pediatr Res

View full text Add to dashboard Cite

The goal of these experiments was to determine the presence and mechanistic basis of flow-induced dilation in mesenteric artery from 3-d-old swine. In the first experiment, in vitro gut loops were perfused from a blood-filled reservoir under controlled-flow conditions, and flow was progressively increased from~40 % to~170% in six increments by manipulation of pump speed. Under control conditions, vascular resistance significantly decreased after each step increase in flow rate. WMonomethyl-t-arginine (LNMMA; 10-4 M), an arginine analog that blocks nitric oxide production, eliminated this flow-induced dilation, but only for the step increases in flow at rates above the baseline flow rate. For step increases below the baseline rate, LNMMA caused a simple parallel shift of the resistance-flow rate curve upward. Phenylephrine (10-6 M), an (X l-agonist which has no effect on nitric oxide production or half-life, did not eliminate flow-induced dilation, but instead caused a simple parallel shift of the resistance-flow rate curve upward across the entire range of flows studied. In the second experiment, a 3-cm segment of mesenteric artery was perfused with Krebs buffer at two flow rates: 10 and 25 mU min. The effluent from the rnesFlow-induced dil ation is a vascular phenomenon wh erein aug me ntation of flow rate throu gh an art ery res ults in vasodilation of that ves sel (1). Th e proc ess was init iall y described in large conduit arteries and was presumed to be part of series of va scular adjustments which facilitate oxygen delivery during exercise (1, 2). In this sce nario, resistance vessels within the microcir cul ation of co ntrac ting muscle dil ate in response to a metaboli c feedb ack signal, an action which decre ases downstrea m vascular resista nce. This hemodynamic ch ange increases flow rate throu gh the co nduit ves se ls leading to the mu scl e. Th e stimulus of inc reas ed flow rate induces dil ation of the conduit vessels, an action which maximizes vascular conduct ance . Subsequent studies hav e identified flow-induced dilation within arterioles (3) and have establ ish ed that flowinduced dil ation is an endo thelium-dependent process, that is, enteric artery segment was suffused onto a deendothelialized, phenylephrine-precontracted ring of swine carotid artery; relaxation of this bioassay vessel served as an index of release of relaxing factors from the mesenteric artery segment. Under control conditions, increase in the mesenteric artery flow rate caused a 60% relaxation of the bioassay vessel. This effect was eliminated by the addition of LNMMA to the buffer (10-4 M), but not by the addition of indomethacin (10-5 M). Flow-induced dilation occurs in the mesenteric artery of 3-d-old swine. This vascular phenomenon appears to be mediated by nitric oxide, but only at flows above the baseline flow rate. The mechanism(s) responsible for this phenomenon at lower flow rates is not clear. (Pediatr Res 38: 783-791, 1995) Abbreviations NO, nitric oxide LNMMA, W-monomethyl-i. -arginine (a-v)02' arteriov...

show abstract

“…The myogenic impairment may particularly concern medullary blood flow autoregula tion [8], perhaps as a consequence of vessel geometry [57], Many factors can impair the myogenic autoregulatory tone of blood ves sels. as emphasized long ago by Folkow [14,15] and recently by Johnson [16].…”

Section: Discussionmentioning

confidence: 90%

“…The above postulation was based on the following premises: (1) an earlier demonstra tion by Waugh [11] that almost perfect blood flow autoregulation, apparently myogenically induced, took place over a wide pres sure range with minimal or undetectable change in urine flow rate as well as intrarenal venous pressure; (2) the findings that both cortical and medullary blood flow can autoregulate very efficiently with pressure change [12,13]; (3) good experimental conditions must be maintained to demonstrate good vascular autoregulatory reactions to intralu minal pressure change [14][15][16], and (4) the recent finding that renal blood flow and GFR are perfectly autoregulated normally over a wide pressure range in conscious dogs on normal sodium intakes, presumably chiefly on a myogenic basis [17]. Autoregula tion of renal blood flow is an intrinsic renal function in which disproportionately smaller changes in blood flow occur as a function of change in arterial pressure [18,19] or, more properly, change in renal arteriovenous pres sure gradient for flow [18.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Modest Pressure Natriuresis and Autoregulation during Water Diuresis in Dogs

Waugh

1991

J Vasc Res

View full text Add to dashboard Cite

The effects of renal arterial pressure change on renal output of sodium and volume were measured during water diuresis in 25 chloralose-anesthetized dogs. Conditions included a minimal invasive stress, limited sodium administration, and mean renal arterial pressures varied suprarenally, by aortic balloon inflation to lowermost levels of 82–106 mm Hg. Group A dogs received no aldosterone; group B, C and D dogs were given aldosterone. Dogs of group C also received (1-Sar, 8-Ile)-angiotensin II. Group D dogs received phenylephrine which elevated arterial and right atrial pressures moderately without decrease in renal blood flow. In groups A, B and C, mean changes in sodium output, volume output, fractional excretions and free water clearances were not detectable with mean renal arterial pressure reductions, which averaged 29 ± 2.9, 22 ± 2.8 and 27 ± 5.2 mm Hg, respectively. Right atrial pressures, effective renal blood flows and glomerular filtration rates did not change with the renal arterial pressure changes in these groups. In the group D dogs, during the larger pressure reductions of 54 ± 6.6 mm Hg from higher values of 158 ± 7.0 mm Hg, mean urine flow and effective renal blood flow remained constant while glomerular filtration rate and sodium output decreased only slightly. Output efficiency ratios related to perfusion pressure were calculated. With no more than modest pressure-induced excretory changes, it is concluded that excretory sodium and urinary volume autoregulation in concert with nearly perfect circulatory autoregulation were demonstrated with regionally varied mean renal arterial pressure. The same preglomerular myogenic responses to transvascular pressure, which restrict glomerular and transcapillary pressures, are viewed dominantly responsible for both circulatory and excretory autoregulation under normal conditions of minimal stress and low fractional sodium excretions. Homeostatic implications are discussed concerning likely relevance to the Guyton-Coleman theory for the long-term control of arterial blood pressure.

show abstract

Autoregulation of blood flow.

Cited by 359 publications

References 126 publications

Effect of Carbogen, Oxygen and Intraocular Pressure on Heidelberg Retina Flowmeter Parameter ‘Flow’ Measured at the Papilla

Effect of Carbogen, Oxygen and Intraocular Pressure on Heidelberg Retina Flowmeter Parameter ‘Flow’ Measured at the Papilla

Flow-Induced Dilation in Newborn Intestine

Modest Pressure Natriuresis and Autoregulation during Water Diuresis in Dogs

Contact Info

Product

Resources

About