11 research outputs found
Role of potassium and calcium channels in sevoflurane-mediated vasodilation in the foeto-placental circulation
<p>Abstract</p> <p>Background</p> <p>Sevoflurane has been demonstrated to vasodilate the foeto-placental vasculature. We aimed to determine the contribution of modulation of potassium and calcium channel function to the vasodilatory effect of sevoflurane in isolated human chorionic plate arterial rings.</p> <p>Methods</p> <p>Quadruplicate <it>ex vivo </it>human chorionic plate arterial rings were used in all studies. <b><it>Series 1 and 2 </it></b>examined the role of the K<sup>+ </sup>channel in sevoflurane-mediated vasodilation. Separate experiments examined whether tetraethylammonium, which blocks large conductance calcium activated K<sup>+ </sup>(K<sub>Ca++</sub>) channels (<b><it>Series 1A+B</it></b>) or glibenclamide, which blocks the ATP sensitive K<sup>+ </sup>(K<sub>ATP</sub>) channel (<b><it>Series 2</it></b>), modulated sevoflurane-mediated vasodilation. <b><it>Series 3 – 5 </it></b>examined the role of the Ca<sup>++ </sup>channel in sevoflurane induced vasodilation. Separate experiments examined whether verapamil, which blocks the sarcolemmal voltage-operated Ca<sup>++ </sup>channel (<b><it>Series 3</it></b>), SK&F 96365 an inhibitor of sarcolemmal voltage-independent Ca<sup>++ </sup>channels (<b><it>Series 4A+B</it></b>), or ryanodine an inhibitor of the sarcoplasmic reticulum Ca<sup>++ </sup>channel (<b><it>Series 5A+B</it></b>), modulated sevoflurane-mediated vasodilation.</p> <p>Results</p> <p>Sevoflurane produced dose dependent vasodilatation of chorionic plate arterial rings in all studies. Prior blockade of the K<sub>Ca++ </sub>and K<sub>ATP </sub>channels augmented the vasodilator effects of sevoflurane. Furthermore, exposure of rings to sevoflurane in advance of TEA occluded the effects of TEA. Taken together, these findings suggest that sevoflurane blocks K<sup>+ </sup>channels. Blockade of the voltage-operated Ca<sup>++</sup>channels inhibited the vasodilator effects of sevoflurane. In contrast, blockade of the voltage-independent and sarcoplasmic reticulum Ca<sup>++</sup>channels did not alter sevoflurane vasodilation.</p> <p>Conclusion</p> <p>Sevoflurane appears to block chorionic arterial K<sub>Ca++ </sub>and K<sub>ATP </sub>channels. Sevoflurane also blocks voltage-operated calcium channels, and exerts a net vasodilatory effect in the <it>in vitro </it>foeto-placental circulation.</p
Ethnic differences translate to inadequacy of high-risk screening for gestational diabetes mellitus in an Asian population: a cohort study
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Extramedullary Plasmacytoma of the Pancreas Complicated with Left-Sided Portal Hypertension—a Case Report and Literature Review
Body fat in Singaporean infants: Development of body fat prediction equations in Asian newborns
10.1038/ejcn.2013.69European Journal of Clinical Nutrition679922-927EJCNEGUSTO (Growing up towards Healthy Outcomes