Bay K 8644 enhances the outflow of [3H]-noradrenaline and [3H]-DOPEG from isolated rat atria

María C. Camilión de Hurtado, Oscar A. Gende, Horacio E. Cingolani

Research output: Contribution to journalArticlepeer-review


The effect of Bay K 8644 (a dihydropyridine Ca2+-channel activator), was examined on spontaneous and stimulus-evoked release of tritium from isolated rat atria prelabelled with [3H]-noradrenaline. Bay K8644 (3μmol/l) significantly increased atrial rate from 206±7 to 259±9 beats·min-1 (P<0.05) and also tritium outflow (expressed as fractional rate of loss in min- × 103) from 6.49±0.35 to 8.61±0.74 (P<0.05). Neither the maximal rate nor the overflow of tritium induced by stimulation of sympathetic nerve terminals was changed by the compound. The increase in basal tritium outflow produced by Bay K 8644 was calcium-dependent. However, it could not be antagonized by nitrendipine. The overflow of tritium induced by Bay K 8644 consisted mainly of 3,4-dihydroxyphenylglycol ([3H]-DOPEG), indicating that the compound produces a leakage from the storage vesicles of sympathetic nerve terminals of the isolated rat atria.

Original languageEnglish (US)
Pages (from-to)603-608
Number of pages6
JournalNaunyn-Schmiedeberg's Archives of Pharmacology
Issue number6
StatePublished - Jun 1991
Externally publishedYes


  • Adrenergic nerve endings
  • Bay K 8644
  • Rat atria
  • Tritium efflux
  • [H]-noradrenaline

ASJC Scopus subject areas

  • Pharmacology


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