Sympathetic responses during saline infusion into the veins of an occluded limb

Cui, Jian; McQuillan, Patrick; Moradkhan, Raman; Pagana, Charles; Sinoway, Lawrence I.

doi:10.1113/jphysiol.2009.173237

Cited by 28 publications

(41 citation statements)

References 46 publications

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“…After baseline measurements, a modified Bier block procedure was utilized to locally administer NS (control) or Px (P2 receptor antagonist) into the occluded vasculature of the dominant forearm, as previously described (9,10). Briefly, the forearm vasculature was partially drained by elevating the forearm for 1-2 min during which a tight elastic wrapping was applied from the wrist to the elbow.…”

Section: In Vivo Human Protocolmentioning

confidence: 99%

Exaggerated exercise pressor reflex in adults with moderately elevated systolic blood pressure: role of purinergic receptors

Greaney

Matthews

Boggs

et al. 2014

American Journal of Physiology-Heart and Circulatory Physiology

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The neurocirculatory responses to exercise are exaggerated in hypertension, increasing cardiovascular risk, yet the mechanisms remain incompletely understood. The aim of this study was to examine the in vitro effectiveness of pyridoxal-5-phosphate as a purinergic (P2) receptor antagonist in isolated murine dorsal root ganglia (DRG) neurons and the in vivo contribution of P2 receptors to the neurocirculatory responses to exercise in older adults with moderately elevated systolic blood pressure (BP). In vitro, pyridoxal-5-phosphate attenuated the ATP-induced increases in [Ca 2ϩ ]i (73 Ϯ 15 vs. 11 Ϯ 3 nM; P Ͻ 0.05). In vivo, muscle sympathetic nerve activity (MSNA; peroneal microneurography) and arterial BP (Finometer) were assessed during exercise pressor reflex activation (static handgrip followed by postexercise ischemia; PEI) during a control trial (normal saline) and localized P2 receptor blockade (pyridoxal-5-phosphate). Compared with normotensive adults (63 Ϯ 2 yr, 117 Ϯ 2/70 Ϯ 2 mmHg), adults with moderately elevated systolic BP (65 Ϯ 1 yr, 138 Ϯ 5/79 Ϯ 3 mmHg) demonstrated greater increases in MSNA and BP during handgrip and PEI. Compared with the control trial, local antagonism of P2 receptors during PEI partially attenuated MSNA (39 Ϯ 4 vs. 34 Ϯ 5 bursts/min; P Ͻ 0.05) in adults with moderately elevated systolic BP. In conclusion, these data demonstrate pyridoxal-5-phosphate is an effective P2 receptor antagonist in isolated DRG neurons, which are of particular relevance to the exercise pressor reflex. Furthermore, these findings indicate that exercise pressor reflex function is exaggerated in older adults with moderately elevated systolic BP and further suggest a modest role of purinergic receptors in evoking the abnormally large reflex-mediated increases in sympathetic activity during exercise in this clinical population.hypertension; metaboreflex; muscle sympathetic nerve activity; calcium imaging; dorsal root ganglia AUGMENTED PRESSOR RESPONSES to exercise are associated with adverse cardiovascular and cerebrovascular events during and after physical activity (22,34,45). Additionally, nonhypertensive individuals with an exaggerated blood pressure (BP) response to exercise are more likely to develop clinical hypertension (12, 53) and are at higher risk of cardiovascular death compared with those with a normal BP response (57, 61). This risk is further modified by baseline hypertension status (61), making exaggerated BP responses to acute exercise especially problematic in adults with chronically elevated resting BP. Resting systolic BP increases with advancing age, such that ϳ65% of older adults have a resting systolic BP in the high-normal or stage I hypertensive range (i.e., 130 -159 mmHg) (5, 16, 40). Therefore, examining neurocirculatory regulation during exercise in this population is clinically relevant.Muscle contraction causes intensity-dependent increases in arterial BP, heart rate (HR), and sympathetic nerve activity (SNA). Afferent feedback from the exercising skeletal muscle is an import...

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Section: In Vivo Human Protocolmentioning

confidence: 99%

Exaggerated exercise pressor reflex in adults with moderately elevated systolic blood pressure: role of purinergic receptors

Greaney

Matthews

Boggs

et al. 2014

American Journal of Physiology-Heart and Circulatory Physiology

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“…While the data in humans are limited to only a few studies (2)(3)(4)(5)(6), there is evidence that peripheral venous distension elicits sympathoexcitation and increases blood pressure. For example, Cui et al (5) found that saline infusion into an antecubital vein of an occluded limb resulted in a nearly twofold increase in muscle sympathetic burst frequency.…”

mentioning

confidence: 99%

“…For example, Cui et al (5) found that saline infusion into an antecubital vein of an occluded limb resulted in a nearly twofold increase in muscle sympathetic burst frequency. This sympathoexcitatory response was later shown to be inhibited by local nerve blockade via lidocaine (6), suggesting that peripheral venous distension initiates a blood pressure raising reflex that is initiated by sensory neurons.…”

mentioning

confidence: 99%

Peripheral venous distension elicits a blood pressure raising reflex in young and middle-aged adults

Matthews

Michael

Coyle

et al. 2016

American Journal of Physiology-Regulatory, Integrative and Comp

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Wenner MM, Farquhar WB. Peripheral venous distension elicits a blood pressure raising reflex in young and middle-aged adults. Am J Physiol Regul Integr Comp Physiol 310: R1128 -R1133, 2016. First published April 6, 2016 doi:10.1152/ajpregu.00438.2015.-Distension of peripheral veins in humans elicits a pressor and sympathoexcitatory response that is mediated through group III/IV skeletal muscle afferents. There is some evidence that autonomic reflexes mediated by these sensory fibers are blunted with increasing age, yet to date the venous distension reflex has only been studied in young adults. Therefore, we tested the hypothesis that the venous distension reflex would be attenuated in middle-aged compared with young adults. Nineteen young (14 men/5 women, 25 Ϯ 1 yr) and 13 middle-aged (9 men/4 women, 50 Ϯ 2 yr) healthy normotensive participants underwent venous distension via saline infusion through a retrograde intravenous catheter in an antecubital vein during limb occlusion. Beat-by-beat blood pressure, muscle sympathetic nerve activity (MSNA), and model flow-derived cardiac output (Q), and total peripheral resistance (TPR) were recorded throughout the trial. Mean arterial pressure (MAP) increased during the venous distension in both young (baseline 83 Ϯ 2, peak 94 Ϯ 3 mmHg; P Ͻ 0.05) and middle-aged adults (baseline 88 Ϯ 2, peak 103 Ϯ 3 mmHg; P Ͻ 0.05). MSNA also increased in both groups [young: baseline 886 Ϯ 143, peak 1,961 Ϯ 242 arbitrary units (AU)/min; middle-aged: baseline 1,164 Ϯ 225, peak 2,515 Ϯ 404 AU/min; both P Ͻ 0.05]. TPR (P Ͻ 0.001), but not Q (P ϭ 0.76), increased during the trial. However, the observed increases in blood pressure, MSNA, and TPR were similar between young and middle-aged adults. Additionally, no correlation was found between age and the response to venous distension (all P Ͼ 0.05). These findings suggest that peripheral venous distension elicits a pressor and sympathetic response in middle-aged adults similar to the response observed in young adults.age; sympathetic; MSNA VENOUS DISTENSION ELICITS a pressor and sympathoexcitatory response that is mediated by group III/IV sensory fibers. The venous distension reflex can respond to distension of small vessels located within the skeletal muscle caused by increased blood flow (11), as occurs during skeletal muscle contraction. Haouzi et al. (12) found that in anesthetized cats, distension of the small veins by mechanical or pharmacological means resulted in activation of both group III and group IV skeletal muscle afferent nerves, with a preference for the latter. Similarly, Yamauchi et al. (33) reported that injections of Ringer's solution into the left femoral vein of decerebrate rats during circulatory occlusion caused a pressor response that was volume dependent.While the data in humans are limited to only a few studies (2-6), there is evidence that peripheral venous distension elicits sympathoexcitation and increases blood pressure. For example, Cui et al. (5) found that saline infusion into an antecubital vein of an occ...

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“…Our recent reports (7)(8)(9)(10) have shown that volume infusion (saline or albumin solution, 5% forearm volume, ϳ50 ml) into the veins of an occluded forearm evokes reflex increases in muscle sympathetic nerve activity (MSNA) and BP in human subjects. The magnitude of the MSNA and BP responses depends on the volume and the rate of the infusate during arm vein distension (8).…”

mentioning

confidence: 99%

“…Thus, we speculate that the major determinant of the response we have noted is the deformation of the vessels and/or pressure gradient generated across the vessels. It should be noted that all of these data regarding the venous distension reflex in humans (7)(8)(9)(10) and rats (33) were obtained with the volume infusion model. We speculate that it is necessary to develop a noninfusion approach to test the venous distension reflex.…”

mentioning

confidence: 99%

Limb suction evoked during arterial occlusion causes systemic sympathetic activity in humans

Cui

Blaha

Herr

et al. 2015

American Journal of Physiology-Regulatory, Integrative and Comp

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-Venous saline infusions in an arterially occluded forearm evokes reflex increases in muscle sympathetic nerve activity (MSNA) and blood pressure (BP). We hypothesized that the application of suction to the human limbs would activate this venous distension reflex and raise sympathetic outflow. We placed airtight pressure tanks and applied 100 mmHg negative pressure to an arterially occluded limb (occlusion and suction, O&S) to induce tissue deformation without fluid translocation. BP, heart rate (HR), and MSNA were assessed in 19 healthy subjects during 2 min of arm or leg O&S. Occlusion without suction served as a control. During a separate visit, saline (5% forearm volume) was infused into veins of the arterially occluded arm (n ϭ 13). The O&S increased limb circumference, MSNA burst rate (arm: ⌬6.7 Ϯ 0.7; leg: ⌬6.8 Ϯ 0.7 bursts/min), and total activity (arm: ⌬199 Ϯ 14; leg: ⌬172 Ϯ 22 units/min) and BP (arm: ⌬4.3 Ϯ 0.3; leg: ⌬9.4 Ϯ 1.4 mmHg) from the baseline. The MSNA and BP responses during arm O&S correlated with those during leg O&S. Occlusion alone had no effect on MSNA and BP. MSNA (r ϭ 0.607) responses during arm O&S correlated with those evoked by the saline infusion into the arm. These correlations suggest that sympathetic activation during limb O&S is likely, at least partially, to be evoked via the venous distension reflex. These data suggest that suction of an occluded limb evokes sympathetic activation and that the limb venous distension reflex exists in arms and legs of normal humans.autonomic; blood pressure regulation; vessel PRIOR STUDIES HAVE SHOWN THAT the distension of abdominal veins increases sympathetic efferent activity in rabbits (2) and dogs (12). Limb venous ligation evokes vasoconstriction in both the occluded and contralateral extremities in dogs (5). Evidence in animals suggests that afferent nerve endings in peripheral veins may sense regional blood volume changes and, in turn, contribute to the blood pressure (BP) regulation via a reflex response in cats (11, 21), rabbits (2), and dogs (12). Venous distension increases the discharge of group III and IV afferent nerves in cat hindlimbs (18).Our recent reports (7-10) have shown that volume infusion (saline or albumin solution, 5% forearm volume, ϳ50 ml) into the veins of an occluded forearm evokes reflex increases in muscle sympathetic nerve activity (MSNA) and BP in human subjects. The magnitude of the MSNA and BP responses depends on the volume and the rate of the infusate during arm vein distension (8). When lidocaine is added to the forearm infusate, the MSNA and BP responses to venous distension are abolished (9). These observations clearly suggest that limb venous distension evokes a sympathoexcitatory reflex (termed venous distension reflex) and, thus, increases BP in humans. Of note, a recent report by Yamauchi et al. (33) has shown this reflex is also present in rats. Additionally, we have shown that venous infusion of albumin evokes a larger and more sustained increase in MSNA and BP than those with infusion of equal vo...

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Sympathetic responses during saline infusion into the veins of an occluded limb

Cited by 28 publications

References 46 publications

Exaggerated exercise pressor reflex in adults with moderately elevated systolic blood pressure: role of purinergic receptors

Exaggerated exercise pressor reflex in adults with moderately elevated systolic blood pressure: role of purinergic receptors

Peripheral venous distension elicits a blood pressure raising reflex in young and middle-aged adults

Limb suction evoked during arterial occlusion causes systemic sympathetic activity in humans

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