Spinoparabrachial projection neurons form distinct classes in the mouse dorsal horn

Browne, T. J., Smith, K. M., Gradwell, M. A., Iredale, J. A., Dayas, C. V., Callister, R. J., Hughes, D. I. and Graham, B. A. (2021) Spinoparabrachial projection neurons form distinct classes in the mouse dorsal horn. Pain, 162(7), pp. 1977-1994. (doi: 10.1097/j.pain.0000000000002194) (PMID:33779126) (PMCID:PMC8208100)

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Abstract

Projection neurons in the spinal dorsal horn relay sensory information to higher brain centres. The activation of these populations is shaped by afferent input from the periphery, descending input from the brain, and input from local interneuron circuits. Much of our recent understanding of dorsal horn circuitry comes from studies in transgenic mice; however, information on projection neurons is still based largely on studies in monkey, cat, and rat. We used viral labelling to identify and record from mouse parabrachial nucleus (PBN) projecting neurons located in the dorsal horn of spinal cord slices. Overall, mouse lamina I spinoparabrachial projection neurons (SPBNs) exhibit many electrophysiological and morphological features that overlap with rat. Unbiased cluster analysis distinguished 4 distinct subpopulations of lamina I SPBNs, based on their electrophysiological properties that may underlie different sensory signalling features in each group. We also provide novel information on SPBNs in the deeper lamina (III-V), which have not been previously studied by patch clamp analysis. These neurons exhibited higher action potential discharge frequencies and received weaker excitatory synaptic input than lamina I SPBNs, suggesting this deeper population produces different sensory codes destined for the PBN. Mouse SPBNs from both regions (laminae I and III-V) were often seen to give off local axon collaterals, and we provide neuroanatomical evidence they contribute to excitatory input to dorsal horn circuits. These data provide novel information to implicate excitatory input from parabrachial projection neuron in dorsal horn circuit activity during processing of nociceptive information, as well as defining deep dorsal horn projection neurons that provide an alternative route by which sensory information can reach the PBN.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Hughes, Dr David I
Authors: Browne, T. J., Smith, K. M., Gradwell, M. A., Iredale, J. A., Dayas, C. V., Callister, R. J., Hughes, D. I., and Graham, B. A.
College/School:College of Medical Veterinary and Life Sciences > Institute of Neuroscience and Psychology
Journal Name:Pain
Publisher:Lippincott, Williams and Wilkins
ISSN:0304-3959
ISSN (Online):1872-6623
Published Online:22 February 2021
Copyright Holders:Copyright © 2021 The Authors
First Published:First published in Pain 162(7): 1977-1994
Publisher Policy:Reproduced under a Creative Commons License

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
165961Modulating cutaneous afferent input: Identifying a source of presynaptic (axo-axonic) inputs in the mouse spinal dorsal hornDavid I HughesBiotechnology and Biological Sciences Research Council (BBSRC)BB/J000620/1NP - Centre for Neuroscience