The effects of catecholamines on pumping activity in isolated bovine mesenteric lymphatics.

McHale, Noel G.; Roddie, I. C.

doi:10.1113/jphysiol.1983.sp014687

Cited by 71 publications

(72 citation statements)

References 11 publications

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“…Our data demonstrating the constrictive effect of NE, U-46619, and ET-1 in human thoracic ducts from a larger sample group thus confirm and extend upon that observation. Furthermore, our observations are in agreement with in vitro studies from other human and animal lymphatics (3,21,34,36,38). We observed the order of contractile efficacy ET-1 Ϸ U-46619 Ͼ NE in the human thoracic duct.…”

Section: Discussionsupporting

confidence: 82%

Human thoracic duct in vitro: diameter-tension properties, spontaneous and evoked contractile activity

Telinius

Drewsen

Pilegaard

et al. 2010

American Journal of Physiology-Heart and Circulatory Physiology

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The current study characterizes the mechanical properties of the human thoracic duct and demonstrates a role for adrenoceptors, thromboxane, and endothelin receptors in human lymph vessel function. With ethical permission and informed consent, portions of the thoracic duct (2-5 cm) were resected and retrieved at T7-T9 during esophageal and cardia cancer surgery. Ring segments (2 mm long) were mounted in a myograph for isometric tension (N/m) measurement. The diameter-tension relationship was established using ducts from 10 individuals. Peak active tension of 6.24 Ϯ 0.75 N/m was observed with a corresponding passive tension of 3.11 Ϯ 0.67 N/m and average internal diameter of 2.21 mm. The equivalent active and passive transmural pressures by LaPlace's law were 47.3 Ϯ 4.7 and 20.6 Ϯ 3.2 mmHg, respectively. Subsequently, pharmacology was performed on rings from 15 ducts that were normalized by stretching them until an equivalent pressure of 21 mmHg was calculable from the wall tension. At low concentrations, norepinephrine, endothelin-1, and the thromboxane-A2 analog U-46619 evoked phasic contractions (analogous to lymphatic pumping), whereas at higher contractions they induced tonic activity (maximum tension values of 4.46 Ϯ 0.63, 5.90 Ϯ 1.4, and 6.78 Ϯ 1.4 N/m, respectively). Spontaneous activity was observed in 44% of ducts while 51% of all the segments produced phasic contractions after agonist application. Acetylcholine and bradykinin relaxed norepinephrine preconstrictions by ϳ20% and ϳ40%, respectively. These results demonstrate that the human thoracic duct can develop wall tensions that permit contractility to be maintained across a wide range of transmural pressures and that isolated ducts contract in response to important vasoactive agents. lymphatic system; lymph pump; lymphangion; lymphatic smooth muscle THE EXCESS FLUID AND PROTEIN of the interstitial spaces in almost all tissues of the body are collected and removed by the lymphatic system. The lymphatic capillaries converge into larger collecting lymphatics, and, ultimately, these terminate into large transport vessels, which return lymph to the blood circulation. The lymphatic system lacks a central pump to drive the transport of lymph. Instead, it is generally accepted that the lymphatic smooth muscle cells (LSMCs) in the collecting and transporting lymphatic vessel wall are responsible for propelling lymph forward by intrinsic contractions. The lymphatic vessels responsible for pumping are comprised of multiple contractile segments separated by unidirectional valves to prevent backflow, termed a lymphangion, and each lymphangion performs much like a cardiac ventricle to provide unidirectional pumping. The contractile part of the lymphatic vasculature can thus be likened to a system of ventricles in series (27). The thoracic duct is the largest lymphatic vessel in the human body. Under normal conditions (i.e., in healthy individuals), it is a low-flow system that drains up to 1 ml/min to the venous circulation (30,44). The volume and flow of lymph a...

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Section: Discussionsupporting

confidence: 82%

Human thoracic duct in vitro: diameter-tension properties, spontaneous and evoked contractile activity

Telinius

Drewsen

Pilegaard

et al. 2010

American Journal of Physiology-Heart and Circulatory Physiology

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“…Furthermore, the decrease in Jnet caused by inhibitors in hydrothoraces of increasing size (0.5-5 mL) is independent of Vliq, in line with the inhibition of an active transport [30][31][32][33], while lymphatic drainage should increase with Vliq [53]. Similar to what is found in alveolar epithelium [90], the active transport is enhanced by b 2 -receptor stimulation [31,32,34], which causes a concomitant depression of lymphatic drainage [91]. The solute-coupled liquid outflow (Js-c) should occur on both pleurae, opposing filtration on the parietal, and enhancing absorption on the visceral side [8].…”

Section: Liquid Exchangessupporting

confidence: 67%

Physiology and pathophysiology of pleural fluid turnover

Zocchi¹

2002

Eur Respir J

183

102

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Tight control of the volume and composition of the pleural liquid is necessary to ensure an efficient mechanical coupling between lung and chest wall. Liquid enters the pleural space through the parietal pleura down a net filtering pressure gradient. Liquid removal is provided by an absorptive pressure gradient through the visceral pleura, by lymphatic drainage through the stomas of the parietal pleura, and by cellular mechanisms. Indeed, contrary to what was believed in the past, pleural mesothelial cells are metabolically active, and possess the cellular features for active transport of solutes, including vesicular transport of protein. Furthermore, the mesothelium was shown, on the basis of recent experimental evidence, both in vivo and in vitro, to be a less permeable barrier than previously believed, being provided with permeability characteristics similar to those of the microvascular endothelium. Direct assessment of the relative contribution of the different mechanisms of pleural fluid removal is difficult, due to the difficulty in measuring the relevant parameters in the appropriate areas, and to the fragility of the mesothelium. The role of the visceral pleura in pleural fluid removal under physiological conditions is supported by a number of findings and considerations.Further evidence indicates that direct lymphatic drainage through the stomas of the parietal pleura is crucial in removing particles and cells, and important in removing protein from the pleural space, but should not be the main effector of fluid removal. Its importance, however, increases markedly in the presence of increased intrapleural liquid loads. Removal of protein and liquid by transcytosis, although likely on the basis of morphological findings and suggested by recent indirect experimental evidence, still needs to be directly proven to occur in the pleura. When pleural liquid volume increases, an imbalance occurs in the forces involved in turnover, which favours fluid removal. In case of a primary abnormality of one ore more of the mechanisms of pleural liquid turnover, a pleural effusion ensues. The factors responsible for pleural effusion may be subdivided into three main categories: those changing transpleural pressure balance, those impairing lymphatic drainage, and those producing increases in mesothelial and capillary endothelial permeability. Except in the first case, pleural fluid protein concentration increases above normal: this feature underlies the classification of pleural effusions into transudative and exudative. Eur Respir J 2002; 20: 1545-1558. The thin layer of liquid present between the pleural surfaces has the important function of providing the mechanical coupling between the chest wall and lung, which ensures instantaneous transmission of perpendicular forces between the two structures, and allows their sliding in response to shearing forces [1,2]. It also provides lubrication of the reciprocal motions of the two structures during breathing. Two views, in part compatible, exist on the nature of t...

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“…Nevertheless, they produce co-ordinated spontaneous activity which results in efficient propulsion of fluid (Hall, Morris & Woolley, 1965;McHale & Roddie, 1976;Olszewski & Engeset, 1980). Our approach in the past has been to study the lymph vessels of large ruminants, which are well developed and more robust than the vessels of smaller species, making them suitable for mechanical studies of pumping activity (McHale & Roddie, 1976;McHale & Thornbury, 1986;McGeown, McHale & Thornbury, 1987).…”

Section: Discussionmentioning

confidence: 99%

Outward Currents in Smooth Muscle Cells Isolated from Sheep Mesenteric Lymphatics

Cotton

Hollywood

McHale

et al. 1997

The Journal of Physiology

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The patch‐clamp technique was used to measure membrane currents in isolated smooth muscle cells dispersed from sheep mesenteric lymphatics. Depolarizing steps positive to −30 mV evoked rapid inward currents followed by noisy outward currents. Nifedipine (1 μM) markedly reduced the outward current, while Bay K 8644 (1 μM) enhanced it. Up to 90% of the outward current was also blocked by iberiotoxin (Kd= 36 nM). Large conductance (304 ±15 pS, 7 cells), Ca2+‐ and voltage‐sensitive channels were observed during single‐channel recordings on inside‐out patches using symmetrical 140 mM K+ solutions (at 37 °C). The voltage required for half‐maximal activation of the channels (V½) shifted in the hyperpolarizing direction by 146 mV per 10‐fold increase in [Ca2+]i. In whole‐cell experiments a voltage‐dependent outward current remained when the Ca2+‐activated current was blocked with penitrem A (100 nM). This current activated at potentials positive to −20 mV and demonstrated the phenomenon of voltage‐dependent inactivation (V½=−41 ± 2 mV, slope factor = 18 ± 2 mV, 5 cells). Tetraethylammonium (TEA; 30 mM) reduced the voltage‐dependent current by 75% (Kd= 3.3 mM, 5 cells) while a maximal concentration of 4‐aminopyridine (4‐AP; 10 mM) blocked only 40% of the current. TEA alone had as much effect as TEA and 4‐AP together, suggesting that there are at least two components to the voltage‐sensitive K+ current. These results suggest that lymphatic smooth muscle cells generate a Ca2+‐activated current, largely mediated by large conductance Ca2+‐activated K+ channels, and several components of voltage‐dependent outward current which resemble ‘delayed rectifier’ currents in other smooth muscle preparations.

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The effects of catecholamines on pumping activity in isolated bovine mesenteric lymphatics.

Cited by 71 publications

References 11 publications

Human thoracic duct in vitro: diameter-tension properties, spontaneous and evoked contractile activity

Human thoracic duct in vitro: diameter-tension properties, spontaneous and evoked contractile activity

Physiology and pathophysiology of pleural fluid turnover

Outward Currents in Smooth Muscle Cells Isolated from Sheep Mesenteric Lymphatics

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