Molecular and electrophysiological characterization of GFP-expressing CA1 interneurons in GAD65-GFP mice

PLoS One. 2010 Dec 31;5(12):e15915. doi: 10.1371/journal.pone.0015915.


The use of transgenic mice in which subtypes of neurons are labeled with a fluorescent protein has greatly facilitated modern neuroscience research. GAD65-GFP mice, which have GABAergic interneurons labeled with GFP, are widely used in many research laboratories, although the properties of the labeled cells have not been studied in detail. Here we investigate these cells in the hippocampal area CA1 and show that they constitute ∼20% of interneurons in this area. The majority of them expresses either reelin (70±2%) or vasoactive intestinal peptide (VIP; 15±2%), while expression of parvalbumin and somatostatin is virtually absent. This strongly suggests they originate from the caudal, and not the medial, ganglionic eminence. GFP-labeled interneurons can be subdivided according to the (partially overlapping) expression of neuropeptide Y (42±3%), cholecystokinin (25±3%), calbindin (20±2%) or calretinin (20±2%). Most of these subtypes (with the exception of calretinin-expressing interneurons) target the dendrites of CA1 pyramidal cells. GFP-labeled interneurons mostly show delayed onset of firing around threshold, and regular firing with moderate frequency adaptation at more depolarized potentials.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • CA1 Region, Hippocampal / metabolism*
  • Calbindin 2
  • Calbindins
  • Cell Adhesion Molecules, Neuronal / metabolism
  • Cholecystokinin / metabolism
  • Electrophysiology / methods*
  • Extracellular Matrix Proteins / metabolism
  • Glutamate Decarboxylase / genetics
  • Glutamate Decarboxylase / metabolism*
  • Green Fluorescent Proteins / metabolism*
  • Hippocampus / metabolism
  • Immunohistochemistry / methods
  • Interneurons / metabolism
  • Membrane Potentials
  • Mice
  • Nerve Tissue Proteins / metabolism
  • Neuropeptide Y / metabolism
  • Patch-Clamp Techniques
  • Rats
  • Reelin Protein
  • S100 Calcium Binding Protein G / metabolism
  • Serine Endopeptidases / metabolism
  • Vasoactive Intestinal Peptide / metabolism


  • Calb2 protein, mouse
  • Calb2 protein, rat
  • Calbindin 2
  • Calbindins
  • Cell Adhesion Molecules, Neuronal
  • Extracellular Matrix Proteins
  • Nerve Tissue Proteins
  • Neuropeptide Y
  • Reelin Protein
  • Reln protein, rat
  • S100 Calcium Binding Protein G
  • Green Fluorescent Proteins
  • Vasoactive Intestinal Peptide
  • Cholecystokinin
  • Reln protein, mouse
  • Serine Endopeptidases
  • Glutamate Decarboxylase
  • glutamate decarboxylase 2