The effects of α‐adrenoceptor agonists on intracellular Ca2+ levels in freshly dispersed single smooth muscle cells from rat tail artery

Xiao‐Fang ‐F Li, Margaret E. Kargacin, Christopher R. Triggle

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Abstract

The presence of functional α‐adrenoceptors in freshly dispersed single smooth muscle cells from rat tail arteries was investigated by use of selective α‐adrenoceptor agonists and antagonists. Cirazoline, a selective α1‐adrenoceptor agonist, caused a prazosin‐sensitive, rapid but transient increase in intracellular Ca2+, which was partially inhibited by the voltage‐dependent Ca2+ channel blocker, nifedipine. TL99, an α2‐adrenoceptor agonist, in the presence of prazosin, initiated a slow and sustained increase in intracellular Ca2+ which was partially inhibited by yohimbine and almost completely blocked by nifedipine. In rat tail artery, the effects (dose‐response and time‐response curves) of cirazoline and TL99 on intracellular Ca2+ levels in freshly dispersed single smooth muscle cells were comparable with those obtained with organ bath studies of ring preparations of artery. In freshly dispersed single smooth muscle cells, the time‐course response curves induced by the selective α1‐adrenoceptor agonist, phenylephrine and the selective α2‐adrenoceptor agonist, UK14304, were similar to those observed with cirazoline and TL99, respectively. These results indicate that: (a) functional α1‐ and α2‐adrenoceptors are present in freshly dispersed single smooth muscle cells from rat tail artery and (b) α1‐ and α2‐adrenoceptors are coupled to different cellular processes that lead to an increase in intracellular Ca2+. 1993 British Pharmacological Society

Original languageEnglish
Pages (from-to)1272-1275
Number of pages4
JournalBritish Journal of Pharmacology
Volume109
Issue number4
DOIs
Publication statusPublished - Aug 1993

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Keywords

  • Intracellular Ca
  • rat tail artery
  • single smooth muscle cells
  • α‐adrenoceptors

ASJC Scopus subject areas

  • Pharmacology

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