L‐type Ca2+ channel current characteristics are preserved in rat tail artery myocytes after one‐day storage. (23rd April 2014)

• Record Type: Journal Article
• Authors: Mugnai, P.; Durante, M.; Sgaragli, G.; Saponara, S.; Paliuri, G.; Bova, S.; Fusi, F.
• Is Part Of: Acta physiologica. Volume 211:Number 2(2014:Jun.)
• Page Start: 334
• Page End: 345
• Publication Date: 2014-04-23
• Subjects: Physiology -- Periodicals; Physiology -- Research -- Periodicals; 612
• DOI: 10.1111/apha.12282
• Languages: English
• ISSNs: 1748-1708

Abstract

<abstract abstract-type="main" id="apha12282-abs-0001"> <title>Abstract</title> <sec id="apha12282-sec-0001" sec-type="section"> <title>Aim</title> <p>To develop a cheap and simple method of storing for 24‐h vascular tissue and single myocytes while preserving therein the biophysical and pharmacological characteristics of L‐type Ca<sup>2+</sup> channels and contractile activity.</p> </sec> <sec id="apha12282-sec-0002" sec-type="section"> <title>Methods</title> <p>Rings or vascular smooth muscle cells obtained from the rat tail main artery were used either freshly (R0h and VSMC0h) or stored for 24 h (R24h and VSMC24h) at 4 °C, to record whole‐cell L‐type Ca<sup>2+</sup> currents (<italic>I</italic><sub>C</sub><sub>a(L)</sub>) or measure contractile responses.</p> </sec> <sec id="apha12282-sec-0003" sec-type="section"> <title>Results</title> <p>R0h/VSMC0h and R24h/VSMC24h comparably contracted when stimulated with phenylephrine, high KCl or ATP. In both VSMC0h and VSMC24h, <italic>I</italic><sub>C</sub><sub>a(L)</sub> was identified and characterized as a stable inward current for at least 35 min; <italic>I</italic><sub>C</sub><sub>a(L)</sub> was comparably inhibited by the Ca<sup>2+</sup> antagonists nifedipine, verapamil and diltiazem and increased by the Ca<sup>2+</sup> channel agonist (S)‐(‐)‐Bay K 8644; current density and current–voltage relationships were similar; at more hyperpolarized holding potentials, <italic>I</italic><sub>C</sub><sub>a(L)</sub> intensity increased comparably; nifedipine shifted the steady‐state inactivation curve towards more negative potentials, while verapamil blocked <italic>I</italic><sub>C</sub><sub>a(L)</sub> in a frequency‐dependent manner and slowed down the rate of recovery from inactivation in a comparable way.</p> </sec> <sec id="apha12282-sec-0004" sec-type="section"> <title>Conclusion</title> <p>Findings show that smooth muscle contractile activity and the biophysical and pharmacological features of L‐type Ca<sup>2+</sup> channels are similar in VSMC24h and VSMC0h. The fact that reproducible results were obtained in vascular myocytes up to 24 h after dissociation may facilitate vascular smooth muscle cell investigation by increasing throughput and reducing the number of animals required.</p> </sec> </abstract>