title: The organisation of spinoparabrachial neurons in the mouse.
abstract: The anterolateral tract (ALT), which originates from neurons in lamina I and the deep dorsal horn, represents a major ascending output through which nociceptive information is transmitted to brain areas involved in pain perception. Although there is detailed quantitative information concerning the ALT in the rat, much less is known about this system in the mouse, which is increasingly being used for studies of spinal pain mechanisms because of the availability of genetically modified lines. The aim of this study was therefore to determine the extent to which information about the ALT in the rat can be extrapolated to the mouse. Our results suggest that as in the rat, most lamina I ALT projection neurons in the lumbar enlargement can be retrogradely labelled from the lateral parabrachial area, that the majority of these cells (∼ 90%) express the neurokinin 1 receptor (NK1r), and that these are larger than other NK1r-expressing neurons in this lamina. This means that many lamina I spinoparabrachial cells can be identified in NK1r-immunostained sections from animals that have not received retrograde tracer injections. However, we also observed certain species differences, in particular we found that many spinoparabrachial cells in laminae III and IV lack the NK1r, meaning that they cannot be identified based solely on the expression of this receptor. We also provide evidence that the majority of spinoparabrachial cells are glutamatergic and that some express substance P. These findings will be important for studies designed to unravel the complex neuronal circuitry that underlies spinal pain processing.
authors.affiliation: Institute of Neuroscience and Psychology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom Department of Anatomy, Hokkaido University School of Medicine, Sapporo, Japan.
authors.forename: Darren
authors.initials: D
authors.lastname: Cameron
authors.forename: Erika
authors.initials: E
authors.lastname: Polgár
authors.forename: Maria
authors.initials: M
authors.lastname: Gutierrez-Mecinas
authors.forename: Maria
authors.initials: M
authors.lastname: Gomez-Lima
authors.forename: Masahiko
authors.initials: M
authors.lastname: Watanabe
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Todd
mesh_terms: D000818:Animals; D002772:Cholera Toxin / Q000378:metabolism; D005260:Female; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D065823:Parabrachial Nucleus / Q000166:cytology*; D018040:Receptors, Neurokinin-1 / Q000378:metabolism; D017481:Receptors, Somatostatin / Q000378:metabolism; D011984:Sensory Receptor Cells / Q000502:physiology*; D013116:Spinal Cord / Q000166:cytology*; D018709:Statistics, Nonparametric; D050599:Vesicular Glutamate Transport Protein 2 / Q000378:metabolism; D050495:Vesicular Inhibitory Amino Acid Transport Proteins / Q000378:metabolism
chemical_list: D018040:Receptors, Neurokinin-1; D017481:Receptors, Somatostatin; C493477:Slc17a6 protein, mouse; D050599:Vesicular Glutamate Transport Protein 2; D050495:Vesicular Inhibitory Amino Acid Transport Proteins; C492244:Viaat protein, mouse; C106140:somatostatin receptor sst2A; D002772:Cholera Toxin