Endogenous polyamines modulate Ca2+ channel activity in guinea-pig intestinal smooth muscle

Research output: Contribution to journalArticlepeer-review


The polyamines spermine and spermidine inhibit L-type Ca2+ channels in whole-cell recordings from guinea-pig ileum cells (Gomez and Hellstrand, Pflugers Arch, 430:501-507, 1995 [4]). To study whether they modulate channel activity under physiological conditions, we further investigated their actions on Ca2+ channels and the effects of altered cellular polyamine contents. In inside-out patches, spermine (0.1-1 mM) inhibited channel activity without affecting the amplitude of unitary currents. In cell-attached recordings, addition of spermine to the bath did not influence channel activity in the patch, indicating that its extracellular action is direct and not mediated via passage of the polyamine through the cell membrane. Cellular contents of spermidine and spermine were decreased by about 50% by organ culture of ileum strips for 5 days with the adenosylmethionine decarboxylase inhibitor CGP 48664 (10 microM). This caused enhanced channel activity in cell-attached recordings, suggesting a reduced level of channel block by endogenous polyamines compared with control cells. Whole-cell recordings in the perforated patch mode showed increased current in polyamine-depleted cells, while this was not seen when cells were dialysed with the pipette solution. We conclude that polyamines block Ca2+ channels from the inside as well as the outside of the cell membrane, and that endogenous polyamines in smooth muscle modulate Ca2+ channel activity.
Original languageEnglish
Pages (from-to)445-451
JournalPflügers Archiv
Issue number4
Publication statusPublished - 1999

Subject classification (UKÄ)

  • Physiology

Free keywords

  • Polyamine
  • Smooth muscle
  • Calcium channels


Dive into the research topics of 'Endogenous polyamines modulate Ca2+ channel activity in guinea-pig intestinal smooth muscle'. Together they form a unique fingerprint.

Cite this