The local anesthetic butamben inhibits total and L-type barium currents in PC12 cells

  • Anesth Analg. 2008 Jun;106(6):1778-83. doi: 10.1213/ane.0b013e318172c3a2.
Laurentius J A Rampaart  1 ,  Jeroen P Beekwilder ,  Gertrudis Th H van Kempen ,  Rutgeris J van den Berg ,  Dirk L Ypey
Affiliations
  • 1. Department of Neurophysiology, Leiden University Medical Center (LUMC), Leiden, The Netherlands.
PMID: 18499609 DOI: 10.1213/ane.0b013e318172c3a2
Abstract

Background: Butamben or n-butyl-p-aminobenzoate is a long-acting experimental local anesthetic for the treatment of chronic pain when given as an epidural suspension. We have investigated whether Cav1.2/L-type calcium channels may be a target of this butamben action.

Methods: The effect of butamben on these channels was studied in undifferentiated rat PC12-cells with the whole-cell patch-clamp technique in voltage-clamp. Ba(2+) ions were used as the charge carriers in the Calcium Channel currents, whereas K(+) currents were removed using K(+) free solutions.

Results: Butamben 500 microM reversibly suppressed the total whole-cell barium current by 90% +/- 3% (n = 15), whereas 10 microM nifedipine suppressed this barium current by 75% +/- 7% (n = 6). Preexposure to butamben followed by washout decreased the inhibition by nifidepine to 47% +/- 5% (n = 10). These suppressive effects were not due to the measurement procedure and the drug vehicles in the solutions (<0.1% ethanol; n = 6).

Conclusions: Butamben inhibits the total barium current through expressed Calcium Channel types in PC12 cells, including Cav1.2/L-type channels. Because Cav1.2 channels may also occur in human nociceptive C fibers, this result allows the possibility that these L-type channels are involved in the analgesic action of butamben.

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