Stereoselectivity of butylidenephthalide on non-adrenergic prejunctional voltage-dependent Ca2+ channels in prostatic portion of rat vas deferens

Chung Hung Shih, Chi Ming Chen, Wun Chang Ko

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

The naturally occurring and synthetic butylinenephthalide (Bdph) has two geometric isomers. Z- and E-Bdph were reported to have geometric stereoselectivity for voltage-dependent calcium channels (VDCCs) in Guinea-pig ileum. The aim of this study was to investigate whether the binding of Z- and E-Bdph on prejunctional VDCCs of rat vas deferens (RVD) is stereoselective. The twitch responses to electrical field stimulation (EFS, supramaximal voltage, 1 ms, 0.2 Hz) were recorded on a polygraph. Z- and E-Bdph concentration-dependently inhibited the twitch responses to EFS in full tissue, prostatic portion and epididymal portion of RVD. The pIC50 value of Z-Bdph was greater than that of E-Bdph in the electrically stimulated prostatic portion of RVD, suggesting that the binding of Bdph on the non-adrenergic prejunctional VDCCs of cell membrane is stereoselective. In the prostatic portion, exogenous Ca2+ only partially reversed the twitch inhibition by Z-Bdph, but effectively reversed those by Ca2+ channel blockers, such as verapamil, diltiazem and aspaminol, suggesting that the action mechanisms may be different from those of Ca2+ channel blockers. K+ channel blockers, such as tetraethylammonium (TEA) and 4-aminopyridine (4-AP), may prolong duration of action potential to allow greater Ca2+ entry and induced more release of transmitters. Therefore both blockers via their prejunctional actions reversed the twitch inhibition induced by Z-Bdph in all preparations of RVD by a non-specific antagonism.

Original languageEnglish
Pages (from-to)47-52
Number of pages6
JournalEuropean Journal of Pharmacology
Volume786
DOIs
Publication statusPublished - Sep 5 2016

Keywords

  • Butylinenephthalide (Bdph)
  • Potassium channel blockers
  • Rat vas deferens
  • StereoSelectivity
  • TwiTch response
  • Voltage-dependent calcium channels

ASJC Scopus subject areas

  • Pharmacology

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