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Pflügers Archiv

, Volume 413, Issue 5, pp 565–567 | Cite as

Substance P, like acetylcholine, augments one type of Ca2+ current in isolated smooth muscle cells

  • Lucie H. Clapp
  • Michel B. Vivaudou
  • Joshua J. Singer
  • John V. WalshJr.
Excitable Tissues and Central Nervous Physiology Short Communication

Abstract

Electrophysiological recordings from freshly-dissociated smooth muscle cells from toad stomach revealed that substance P enhances one of two types of Ca2+ currents. That is, substance P enhances the slowly inactivating, high-threshold current but not the fast inactivating, low-threshold current. Acetylcholine has the same effect, but the acetylcholine action is blocked by atropine whereas the substance P action is not, indicating that the two agents act at different receptor sites. Thus substance P, like acetylcholine, has a dual excitatory action on the smooth muscle cells employed in these studies, enhancing a specific type of Ca2+ current, as demonstrated here, and suppressing a voltage-sensitive K+ conductance as previously described [Sims, S.M., Walsh, J.V., Jr. & Singer, J.J. (1986) Am. J. Physiol.251, C580–C587].

Key words

Neuropeptide Muscarinic receptor Voltage Clamp Calcium Channels Patch Clamp 

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Copyright information

© Springer-Verlag 1989

Authors and Affiliations

  • Lucie H. Clapp
    • 1
  • Michel B. Vivaudou
    • 1
  • Joshua J. Singer
    • 1
  • John V. WalshJr.
    • 1
  1. 1.Department of PhysiologyUniversity of Massachusetts Medical SchoolWorcesterUSA

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