Does the Endothelium Play a Role in Flow-Dependent Constriction?

Sipkema, Pieter; Linden, P.J.W. van der; Hoogerwerf, Nico; Westerhof, Nico

doi:10.1159/000158787

Cited by 10 publications

(12 citation statements)

References 17 publications

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“…The average separation of the wires was 4 mm (after stretching the segment). The PSS in the infusion pipette had the same composition as the bath solution (the same concentration of 5 Ca'+ as in the 45Ca2' net uptake or influx experiments and the same concentration of histamine when histamine was used).…”

Section: Materials and Methods Rabbit Facial Veinmentioning

confidence: 99%

Intraluminal flow increases vascular tone and 45Ca2+ influx in the rabbit facial vein.

Henrion

Laher

Bevan

1992

Circulation Research

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The buccal segment of the rabbit facial vein exhibits a high level of myogenic tone in vitro that develops only in stretched vessel segments between 330 and 44°C. The infusion of physiological salt solution into the lumen of 2-mm-long rabbit facial vein segments induced a flow rate-dependent increase in wall tone, both in the presence (37°C) and absence (30°C) of myogenic tone. In calcium-free physiological solution with EGTA, neither flow nor stretch-induced tone was observed. This flow-induced contraction was associated with an increase in 45Ca2' unidirectional influx and net uptake. These measurements correlated positively with the level of the associated constrictor responses, both in the presence or absence of myogenic tone.The mean contractile responses to flow (10 and 40 ,tl/min), stretch, and histamine (1 ,uM) were 13%, 28%, 24%, and 33% of the tissue maximal response, respectively. When 45Ca2' influx was expressed in relation to the force development (45Ca21 influx per milligram), the amount of calcium entry was dependent on the stimulus. Values for 45Ca2' influx per milligram in response to flow (10 and 40 ,ul/min) and to histamine (1 ,uM) were not significantly different. The value was significantly lower for the response to stretch. On the other hand, 45Ca2+ net uptake, when expressed per unit force, was similar in response to flow (10 and 40 ,l/min), histamine (1 ,uM), and stretch. We conclude that flow-induced contraction in the rabbit facial vein is associated with Ca2' entry into the smooth muscle cells through a pathway that may be different from that associated with stretch-activated contraction. (Circulation Research 1992;71:339-345) KEY WORDs * flow * veins * blood vessels * contraction * calcium influx * calcium uptake C hanges in intraluminal flow may induce either dilation or constriction in vitro, depending on the level of tone of the smooth muscle cells in the vessels; this phenomenon suggests that the effect of flow is the result of a balance between those forces.' Flow-induced contraction occurs in a variety of isometrically mounted arteries23 and in the perfused pial4 and femoral5 arteries. It is dependent on the presence of extracellular calcium' but not the integrity of the endothelium.14-6 The findings of previous studies indicate that the flow-induced contraction mechanism might be expected to be different from that required by stretchinduced myogenic contraction.7To gain insight into the mechanisms involved in flow-induced contraction and to compare these with those related to stretch, we studied 45Ca 2 influx and net uptake in the rabbit facial vein (RFV). This is an isolated vascular segment that responds by contraction in vitro to both flow and stretch. The RFV possesses a high level of myogenic tone in vitro that is temperature dependent. It is present at 37°C and absent at 30°C. Tone that is due to other stimuli, including flow (the present study), is not temperature dependent. sponse to flow in either the presence or the absence of myogenic tone. This allows for the compa...

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Section: Materials and Methods Rabbit Facial Veinmentioning

confidence: 99%

Intraluminal flow increases vascular tone and 45Ca2+ influx in the rabbit facial vein.

Henrion

Laher

Bevan

1992

Circulation Research

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“…Bevan and Joyce [28] reported two opposing effects (constriction and dilatation) as a result of flow in segments of a branch of the rabbit ear artery and suggested the final result to be dependent on the level of wall stress (measured in a wire myograph). In the present study, we used an increased transmural pressure in com parison to our previous reports [6,7], but still we found flow-dependent constriction.…”

Section: Influence O F the Wall Stress And Preconstriction Level On Fmentioning

confidence: 60%

“…This shear stress value is low compared to the physiological range of shear stresses [about 50-80 dyn/cm2, ref. 14], Since we found in earlier studies that the largest changes in diameter occur in the low-flow range [6,7], we did not use higher values in the present experiments.…”

Section: Flow and Shearmentioning

confidence: 99%

“…We recently reported flow-induced constriction in the rabbit femoral artery [6,7], but those experiments were performed at a transmural pressure of 50 cm H20 , while the present experiments were performed at a transmural pressure of 100 cm H20 , a more physiological value for this size of vessel. Bevan and Joyce [28] reported two opposing effects (constriction and dilatation) as a result of flow in segments of a branch of the rabbit ear artery and suggested the final result to be dependent on the level of wall stress (measured in a wire myograph).…”

Section: Influence O F the Wall Stress And Preconstriction Level On Fmentioning

confidence: 99%

“…We subsequently showed a flow-dependent constriction in small rabbit mesenteric arteris [ 14] and in the rabbit femoral artery [6,7], In the latter paper [7], we showed that this phenomenon remained after blocking the forma tion of EDRF with gossypol [15] or inactivation of EDRF by haemoglobin [16]. However, there still might be paral lel ways that were bypassed, i.e.…”

Section: Introductionmentioning

confidence: 99%

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Endothelium Function Is Protected by Albumin and Flow-Induced Constriction Is Independent of Endothelium and Tone in Isolated Rabbit Femoral Artery

Hoogerwerf¹,

Zijlstra²,

Linden³

et al. 1992

J Vasc Res

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To investigate the preservation of endothelial function, we perfused two segments of one rabbit femoral artery (n = 8) in a pressure myograph in parallel, both with Tyrode, but one with 0.6% albumin added. The change in the outer diameter of the vessels [preconstricted with norepinephrine (NE) to 70%] in response to acetylcholine as an indicator of the endothelial function, was repeatedly measured over 5 h after the equilibration. The difference between the acetylcholine responses of the two vessel segments was significant (p < 0.05) after a perfusion period of 4 h. We also investigated whether flow-induced constriction is dependent on (1) the presence of endothelium and (2) the level of preconstriction. We therefore perfused segments of rabbit femoral arteries (n = 5) with Tyrode with 0.6% albumin. If acetylcholine-induced dilatation was present, a flow-diameter relation was determined at two constriction levels: about 60% (high) and 90% (low) of the passive outer diameter. Both determinations were repeated after mechanical endothelium removal (checked functionally and histologically). A similar decrease in diameter (about 7%) with an increase in flow ranging from 0 to 1,330 microliters/min was found in all conditions. We conclude that the addition of (0.6%) albumin protects endothelial function in the rabbit femoral artery when perfused in the low-flow range for a period longer than 4 h. We also found that flow-dependent constriction is neither influenced by the presence of the endothelium nor by the level of tone induced with NE.

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Responses to mechanical stimuli of isolated basilar and femoral arteries of the rhesus monkey are different

Sipkema¹,

Linden²,

Fanton³

et al. 1996

Heart Vessels

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The present study aimed to determine regional differences in diameter response to mechanical stimuli such as flow (shear stress) and transmural pressure (myogenic response) of the isolated basilar artery and femoral artery from Rhesus monkeys. Whether or not spontaneous tone developed, a transmural pressure-diameter relation was determined after the equilibration period. Vessels were then constricted with a submaximal dose of prostaglandin-F(2 alpha) (PGF(2 alpha); 1.23-2 mu M) and a flow-diameter relation (0-2,000 mu l/min) and a pressure-diameter (15-125 cm H(2)O) relation were determined. Endothelium function was tested with the calcium ionophore A-23187 (1.0 mu M). The vessels were then maximally dilated (papaverine, 100 mu M) and a passive pressure-diameter relation was determined. The responses of the basilar and the femoral arteries were markedly different. The basilar artery developed spontaneous tone, while the femoral artery did not. The basilar artery showed flow-induced constriction (P = 0.024), while the femoral artery dilated when flow was increased (P = 0.0005). The myogenic index of the two arteries during treatment with PGF(2 alpha) was not different (P = 0.49) and the strength of the myogenic response was such that the diameter of both arteries stayed constant over the pressure range studied. We conclude that the responses to mechanical stimuli of the basilar artery and the femoral artery of the Rhesus monkey are markedly different.

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Does the Endothelium Play a Role in Flow-Dependent Constriction?

Cited by 10 publications

References 17 publications

Intraluminal flow increases vascular tone and 45Ca2+ influx in the rabbit facial vein.

Intraluminal flow increases vascular tone and 45Ca2+ influx in the rabbit facial vein.

Endothelium Function Is Protected by Albumin and Flow-Induced Constriction Is Independent of Endothelium and Tone in Isolated Rabbit Femoral Artery

Responses to mechanical stimuli of isolated basilar and femoral arteries of the rhesus monkey are different

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