3,5-Dibenzoyl-4-(3-phenoxyphenyl)-1,4-dihydro-2,6-dimethylpyridine (DP7) as a new multidrug resistance reverting agent devoid of effects on vascular smooth muscle contractility

Simona Saponara, Masami Kawase, Anamik Shah, Noboru Motohashi, Joseph Molnar, Katalin Ugocsai, Giampietro Sgaragli, Fabio Fusi

Research output: Contribution to journalArticle

33 Citations (Scopus)


1. The aim of this study was to investigate the effects of 3,5-diacetyl- (DP1-DP5) and 3,5-dibenzoyl-1,4-dihydropyridines (DP6-DP11) on vascular functions in vitro, by comparing their mechanical and electrophysiological actions in rat aorta rings and single rat tail artery myocytes, respectively, and to quantify their multidrug resistance (MDR)-reversing activity in L5178 Y mouse T-lymphoma cells transfected with MDR1 gene. 2. In rat aorta, the 11 compounds tested, but 3,5-dibenzoyl-4-(3-phenoxyphenyl)-1,4-dihydro-2,6- dimethylpyridine (DP7), 3,5-dibenzoyl-4-(3-chlorophenyl)-1,4-dihydro-2,6- dimethylpyridine (DP9), 3,5-dibenzoyl-4-(4-chlorophenyl)-1,4-dihydro-2,6- dimethylpyridine (DP10) and 3,5-dibenzoyl-4-phenyl-1,4-dihydro-2,6- dimethylpyridine (DP11), antagonized 60 mM K + (K60)-induced contraction in a concentration-dependent manner, with IC 50 (M) values ranging between 5.65 × 10 -7 and 2.23 × 10 -5. 3. The 11 dihydropyridines tested, but DP7, inhibited L-type Ca 2+ current recorded in artery myocytes in a concentration- dependent manner, with IC 50 (M) values ranging between 1.12 × 10 -6 and 6.90 × 10 -5. 4. The K +-channel opener cromakalim inhibited the Ca 2+-induced contraction in K30 but not that evoked in K60. On the contrary, DP7 was ineffective in both experimental conditions. 5. When the rings were preincubated with 1 mM Ni 2+ plus 1 μM nifedipine, the response to phenylephrine was significantly reduced by 2,5-di-t-butyl-1,4-benzohydroquinone (BHQ), a well-known endoplasmic reticulum Ca 2+-ATPase inhibitor. DP7 had no effects on this model system. 6. In L5178 MDR cell line, the 11 dihydropyridines tested, but 3,5-diacetyl-4-(2-nitrophenyl)-1,4-dihydro-2,6- dimethylpyridine (DP1), 3,5-diacetyl-4-(3-phenoxyphenyl)-1,4-dihydro-2,6- dimethylpyridine (DP2) and 3,5-diacetyl-4-(3-chlorophenyl)-1,4-dihydro-2,6- dimethylpyridine (DP4), exhibited an MDR-reversing activity, with IC 50 values ranging between 3.02 × 10 -7 and 4.27 × 10 -5, DP7 being the most potent. 7. In conclusion, DP7 may represent a lead compound for the development of potent dihydropyridine MDR chemosensitizers devoid of vascular effects.

Original languageEnglish
Pages (from-to)415-422
Number of pages8
JournalBritish journal of pharmacology
Issue number3
Publication statusPublished - Feb 1 2004


  • Dihydropyridines
  • L-type Ca channel inhibitor
  • MDR reverter
  • Mouse T-lymphoma cell
  • Rat aorta ring
  • Rat tail artery smooth muscle
  • Rhodamine 123
  • Whole-cell patch-clamp

ASJC Scopus subject areas

  • Pharmacology

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