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Author Notes:

Address for reprint requests and other correspondence: S. Hochman, Whitehead Biomedical Research Bldg., Rm. 644, Emory University School of Medicine, 615 Michael St., Atlanta GA 30322 (E-mail: shochm2@emory.edu).

Subject:

Research Funding:

National Institute of Neurological Disorders and Stroke : NINDS

This work was supported by the National Institute of Neurological Disorders and Stroke Grants NS-45248 and NS-40893 to S. Hochman and fellowship award NS-49784 to K. J. Dougherty.

Properties of Mouse Spinal Lamina I GABAergic Interneurons.

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Journal Title:

Journal of Neurophysiology

Volume:

Volume 94, Number 5

Publisher:

, Pages 3221-3227

Type of Work:

Article | Post-print: After Peer Review

Abstract:

Lamina I is a sensory relay region containing projection cells and local interneurons involved in thermal and nociceptive signaling. These neurons differ in morphology, sensory response modality, and firing characteristics. We examined intrinsic properties of mouse lamina I GABAergic neurons expressing enhanced green fluorescent protein (EGFP). GABAergic neuron identity was confirmed by a high correspondence between GABA immunolabeling and EGFP fluorescence. Morphologies of these EGFP+/GABA+ cells were multipolar (65%), fusiform (31%), and pyramidal (4%). In whole cell recordings, cells fired a single spike (44%), tonically (35%), or an initial burst (21%) in response to current steps, representing a subset of reported lamina I firing properties. Membrane properties of tonic and initial burst cells were indistinguishable and these neurons may represent one functional population because, in individual neurons, their firing patterns could interconvert. Single spike cells were less excitable with lower membrane resistivity and higher rheobase. Most fusiform cells (64%) fired tonically while most multipolar cells (56%) fired single spikes. In summary, lamina I inhibitory interneurons are functionally divisible into at least two major groups both of which presumably function to limit excitatory transmission.

Copyright information:

© 2005 The American Physiological Society

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