Effects of semotiadil fumarate, a novel Ca2+ antagonist, on cytosolic Ca2+ level and force of contraction in porcine coronary arteries

Masaaki Kageyama, Teruyuki Yanagisawa, Norio Taira

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9 Citations (Scopus)

Abstract

1 The mechanisms of action of semotiadil fumarate, a novel Ca2+ antagonist, were examined by measuring the cytosolic Ca2+ level ([Ca2+]i) and force of contraction in porcine coronary arteries, and by determining [3H]‐pyrilamine binding to bovine cerebellar membranes. 2 Semotiadil or verapamil (0.1 and 1 μm) inhibited both the high KCl‐induced increases in [Ca2+]i and force in a concentration‐dependent manner. 3 Histamine (30 μm) produced transient increases followed by sustained increases in [Ca2+]i and force, which were inhibited by semotiadil and verapamil (1 and 10 μm).& The agents were different in that semotiadil reduced the maximum [Ca2+]i and force responses to histamine, but not pD2 values, whereas verapamil did reduce the pD2 values for histamine, but not the maximum responses. 4 Verapamil (10 μm), but not semotiadil, inhibited histamine‐induced increases in [Ca2+]i and force in Ca2+‐free solution. Neither semotiadil nor verapamil affected the increases in [Ca2+]i and force induced by caffeine. Semotiadil even at the higher concentration (10 μm) did not displace specific binding of [3H]‐pyrilamine to bovine cerebellar membranes. 5 These results suggest that semotiadil inhibits both KCl‐ and histamine‐induced contractions mainly by blocking voltage‐dependent L‐type Ca2+ channels. 1995 British Pharmacological Society

Original languageEnglish
Pages (from-to)1289-1295
Number of pages7
JournalBritish Journal of Pharmacology
Volume114
Issue number6
DOIs
Publication statusPublished - 1995 Mar

Keywords

  • Ca antagonists
  • Semotiadil
  • cytosolic Ca level
  • force of contraction
  • fura‐2
  • porcine coronary arteries
  • verapamil

ASJC Scopus subject areas

  • Pharmacology

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