Nicotinic and muscarinic acetylcholine responses in differentiated PC12 cells

Katsutoshi Furukawa, Junichi Nabekura, Norio Akaike

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

Nicotinic and muscarinic acetylcholine (ACh) responses were investigated in PC12 cells using the conventional whole-cell and nystatin perforated patch techniques. With the nystatin perforated patch, ACh induced three kinds of ionic currents: a rapid transient inward current, a subsequent transient outward current and a long-lasting slow inward current, whereas only a transient inward current was recorded by conventional whole-cell patch. The transient rapid inward current was mimicked by nicotine, but not by muscarine. On the contrary, the transient outward current and the long-lasting slow inward current were mimicked by muscarine but not by nicotine. Both nicotinic and muscarinic antagonists inhibited the transient inward current and the subsequent outward current in a concentration-dependent manner. The current-voltage relationship for the nicotine-induced transient current showed an inward rectification and the reversal potential was close to the Na+ equilibrium potential. The ACh-, muscarine-, CCh- and oxotremorine-M induced outward currents increased in a sigmoidal fashion with an increase in the concentration. Neither McN-A-343, an M1 agonist, nor oxotremorine, an M2 agonist, mimicked the muscarinic response. The reversal potential of the muscarinic response was close to the K+ equilibrium potential. The muscarinic response was not affected by pre-treatment with pertussis toxin but was enhanced by pre-treatment with Li+. In the cells perfused with Ca2+-free external solution, only the first application of ACh induced the muscarinic response. Calmodulin antagonists reversibly blocked the muscarinic response in a concentration-dependent manner. Neither protein kinase C inhibitor (H-7), protein kinase A inhibitor (H-8), nor Ca-calmodulin dependent kinase II inhibitor (KN-62) affected the muscarinic response. It was concluded that the ACh-induced rapid inward current was passing through non-selectivecation channels coupled with nicotinic ACh receptors. On the other hand, the muscarinic response is mediated by the activation of M3 receptors coupled to IAP-insensitive G-protein which stimulates the phosphatidylinositol pathway through phospholipase C. Consequently, Ca2+ was released by the increase in IP3. Finally, Ca2+-calmodulin binding may lead to opening of the K+ channels.

Original languageEnglish
Pages (from-to)302-310
Number of pages9
JournalBrain research
Volume638
Issue number1-2
DOIs
Publication statusPublished - 1994 Feb 28

Keywords

  • Muscarinic ACh response
  • Nicotinic ACh response
  • Nystatin-perforated patch
  • PC12 cell

ASJC Scopus subject areas

  • Neuroscience(all)
  • Molecular Biology
  • Clinical Neurology
  • Developmental Biology

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