Substance P Activates Ca2+-Permeable Nonselective Cation Channels through a Phosphatidylcholine-Specific Phospholipase C Signaling Pathway in nNOS-Expressing GABAergic Neurons in Visual Cortex

Cereb Cortex. 2016 Feb;26(2):669-682. doi: 10.1093/cercor/bhu233. Epub 2014 Oct 14.


To understand the functions of the neocortex, it is essential to characterize the properties of neurons constituting cortical circuits. Here, we focused on a distinct group of GABAergic neurons that are defined by a specific colocalization of intense labeling for both neuronal nitric oxide synthase (nNOS) and substance P (SP) receptor [neurokinin 1 (NK1) receptors]. We investigated the mechanisms of the SP actions on these neurons in visual cortical slices obtained from young glutamate decarboxylase 67-green fluorescent protein knock-in mice. Bath application of SP induced a nonselective cation current leading to depolarization that was inhibited by the NK1 antagonists in nNOS-immunopositive neurons. Ruthenium red and La(3+), transient receptor potential (TRP) channel blockers, suppressed the SP-induced current. The SP-induced current was mediated by G proteins and suppressed by D609, an inhibitor of phosphatidylcholine-specific phospholipase C (PC-PLC), but not by inhibitors of phosphatidylinositol-specific PLC, adenylate cyclase or Src tyrosine kinases. Ca(2+) imaging experiments under voltage clamp showed that SP induced a rise in intracellular Ca(2+) that was abolished by removal of extracellular Ca(2+) but not by depletion of intracellular Ca(2+) stores. These results suggest that SP regulates nNOS neurons by activating TRP-like Ca(2+)-permeable nonselective cation channels through a PC-PLC-dependent signaling pathway.

Keywords: NK1 receptor; PC-PLC; neuronal nitric oxide synthase; slice; tachykinin.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Anthracenes / pharmacology
  • Boron Compounds / pharmacology
  • Calcium / metabolism*
  • Calcium Channel Blockers / pharmacology
  • Dose-Response Relationship, Drug
  • Electric Stimulation
  • Excitatory Amino Acid Agents / pharmacology
  • GABAergic Neurons / drug effects*
  • GABAergic Neurons / physiology
  • Glutamate Decarboxylase / genetics
  • Glutamate Decarboxylase / metabolism
  • Imidazoles / pharmacology
  • In Vitro Techniques
  • Isoindoles / pharmacology
  • Mice
  • Mice, Transgenic
  • Neurokinin-1 Receptor Antagonists / pharmacology
  • Nitric Oxide Synthase Type III / metabolism*
  • Patch-Clamp Techniques
  • Piperidines / pharmacology
  • Quinolines / pharmacology
  • Quinuclidines / pharmacology
  • Signal Transduction / drug effects
  • Signal Transduction / physiology*
  • Substance P / pharmacology*
  • Type C Phospholipases / metabolism*
  • Visual Cortex / cytology*


  • 10,10-bis(4-pyridinylmethyl)-9(10H)-anthracenone
  • Anthracenes
  • Boron Compounds
  • Calcium Channel Blockers
  • Excitatory Amino Acid Agents
  • Imidazoles
  • Isoindoles
  • Neurokinin-1 Receptor Antagonists
  • Piperidines
  • Quinolines
  • Quinuclidines
  • SB 222200
  • 7,7-diphenyl-2-(1-imino-2-(2-methoxyphenyl)ethyl)perhydroisoindol-4-one
  • SR 140333
  • Substance P
  • 2-aminoethoxydiphenyl borate
  • Nitric Oxide Synthase Type III
  • Type C Phospholipases
  • phosphatidylcholine-specific phospholipase C
  • Glutamate Decarboxylase
  • glutamate decarboxylase 1
  • 1-(2-(3-(4-methoxyphenyl)propoxy)-4-methoxyphenylethyl)-1H-imidazole
  • Calcium