Functional heterogeneity of calretinin-expressing neurons in the mouse superficial dorsal horn: implications for spinal pain processing

Smith, K.M., Boyle, K.A., Madden, J.F., Dickinson, S.A., Jobling, P., Callister, R.J., Hughes, D.I. and Graham, B.A. (2015) Functional heterogeneity of calretinin-expressing neurons in the mouse superficial dorsal horn: implications for spinal pain processing. Journal of Physiology, 593(19), pp. 4319-4339. (doi: 10.1113/JP270855) (PMID:26136181) (PMCID:PMC4594251)

Abstract

The superficial spinal dorsal horn contains a heterogeneous population of neurons that process sensory inputs. Information on the properties of excitatory interneurons in this region is limited. As calretinin is a protein thought to be restricted to an excitatory population in this region, the aim of this study was to characterize calretinin-expressing neurons. Most calretinin cells (85%) exhibited large A-type potassium currents and delayed firing action potential discharge, and received strong excitatory synaptic input, whereas the remainder exhibited hyperpolarization-activated cation currents and low threshold T-type calcium currents, and tonic- or initial bursting firing patterns, and received weak excitatory synaptic input. These respective features are consistent with properties of excitatory and inhibitory interneuron populations in this region of the spinal cord. Our findings have resolved a previously unidentified population of inhibitory interneurons. Furthermore, the contrasting excitability patterns of excitatory and inhibitory calretinin-expressing neurons suggest that they play distinct roles in spinal sensory processing circuits.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Boyle, Dr Kieran and Hughes, Dr David I
• Authors: Smith, K.M., Boyle, K.A., Madden, J.F., Dickinson, S.A., Jobling, P., Callister, R.J., Hughes, D.I., and Graham, B.A.
• College/School: College of Medical Veterinary and Life Sciences > School of Psychology & Neuroscience
• Research Group: Centre for Neuroscience
• Journal Name: Journal of Physiology
• Publisher: Wiley-Blackwell Publishing Ltd.
• ISSN: 0022-3751
• ISSN (Online): 1469-7793

Project Code	Award No	Project Name	Principal Investigator	Funder's Name	Funder Ref	Lead Dept
57107	1	Modulating cutaneous afferent input: Identifying a source of presynaptic (axo-axonic) inputs in the mouse spinal dorsal horn	David I Hughes	Biotechnology and Biological Sciences Research Council (BBSRC)	BB/J000620/1	RI NEUROSCIENCE & PSYCHOLOGY