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KMID : 0811720040080000188
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Korean Journal of Physiology & Pharmacology
2004 Volume.8 No. 0 p.188 ~ p.0
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Stretch-Activated Channels in ANP Release
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Han Jeong-Hee
Kim Sung-Zoo
Cho Kyung-Woo
Kim Sun-Hee
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Abstract
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Mechanical stretch is the most important stimuli for the secretion of atrial ANP. However, the exact mechanism involved in the mechanosignal transduction is still unknown. The aim of the present study is to define the possible role of stretch-activated ion channels (SACs) in the ANP secretion using isolated perfused beating rat atria. An increase in volume load followed by atrial stretch was performed by the elevation of height of outflow catheter connected to the perfused atrium. An increasein resistance without stretch was performed by decreasing the diameter of outflow catheter. Both methods caused similar increases in atrial contractility. Volume load markedly increased ECF translocation (by 40%) and ANP secretion (by 175%) but increasing the resistance did not. Changes in ANP secretion positively correlated to atrial workload (calculated from the multiplication of loaded volume and change in pulse pressure). Gadolinium, an inhibitor of SAC, and 5-nitro-2-(3-phenylpropylamino)benzoic acid, a chloride channel blocker, markedly attenuated stretch-induced increases in contractility, ECF translocation and ANP secretion. However, gadolinium did not affect changes in atrial contractility and ANP secretion induced by increasing resistance (which did not cause atrial stretch). Cytochalasin D, a F-actin disrupter, attenuated stretch- induced changes in atrial contractility and ANP secretion, which were reversed by the pretreatment of phalloidin. An increase in ECF translocation by stretch was markedly decreased by cytochalasin D but this effect was not affected by phalloidin. These results suggest that SACs and cytoskeletons play an important role in the regulation of stretch-induced ANP secretion. Supported by the Korea Health 21 R&D Project, Ministry of Health & Welfare (01-PJ1-PG1-01CH06-0003).
Source: Korean Journal of Physiology & Pharmacology.2004 Oct;8(Suppl I):S139-S139
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KEYWORD
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Stretch, Stretch-activated channel, Atrium, Cytoskeleton, ANP
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