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

• Published in: PloS one 2010-12, Vol.5 (12), p.e15915-e15915
• Main Authors: Wierenga, Corette J, Müllner, Fiona E, Rinke, Ilka, Keck, Tara, Stein, Valentin, Bonhoeffer, Tobias
• Format: Article
• Language: English
• Subjects: Animals; Biology; CA1 Region, Hippocampal - metabolism; Calbindin; Calbindin 2; Calbindins; Calretinin; Cell Adhesion Molecules, Neuronal - metabolism; Cholecystokinin; Cholecystokinin - metabolism; Dendrites; Depolarization; Electrophysiology - methods; Extracellular Matrix Proteins - metabolism; Firing rate; Fluorescence; GABA; Genetic engineering; Glutamate decarboxylase; Glutamate Decarboxylase - genetics; Glutamate Decarboxylase - metabolism; Green fluorescent protein; Green Fluorescent Proteins - metabolism; Hippocampus; Hippocampus - metabolism; Immunoglobulins; Immunohistochemistry - methods; Interneurons; Interneurons - metabolism; Intestine; Laboratories; Laboratory animals; Membrane Potentials; Mice; Morphology; Nerve Tissue Proteins - metabolism; Nervous system; Neurobiology; Neurogenesis; Neurons; Neuropeptide Y; Neuropeptide Y - metabolism; Neurosciences; Parvalbumin; Patch-Clamp Techniques; Phosphorylation; Pyramidal cells; Rats; Reelin protein; Rodents; S100 Calcium Binding Protein G - metabolism; Serine Endopeptidases - metabolism; Somatostatin; Transgenic animals; Transgenic mice; Trends; Vasoactive agents; Vasoactive intestinal peptide; Vasoactive Intestinal Peptide - metabolism; Vasoactive intestinal peptides; γ-Aminobutyric acid
• ISSN: 1932-6203; 1932-6203
• 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.