title: The spino-bulbar-cerebellar pathway: Activation of neurons projecting to the lateral reticular nucleus in the rat in response to noxious mechanical stimuli.
abstract: It is now well established that the cerebellum receives input from nociceptors which may serve to adjust motor programmes in response to pain and injury. In this study, we investigated the possibility that spinoreticular neurons (SRT) which project to a pre-cerebellar nucleus, the lateral reticular nucleus (LRt), respond to noxious mechanical stimulation. Seven adult male rats received stereotaxic injections of the b subunit of cholera toxin in the LRt. Following a 5 day interval, animals were anesthetised with urethane and a noxious mechanical stimulus was applied to the right hind paw. Animals were fixed by perfusion 5min following application of the stimulus. Retrogradely labelled SRT neurons of the lumbar spinal cord were examined for immunoreactivity for phosphorylated ERK (pERK) and the neurokinin-1 (NK-1) receptor. Approximately 15% of SRT cells in deep laminae (IV-VII and X) expressed pERK ipsilateral to the site of the stimulus. Around 60% of SRT cells with the NK-1 receptor expressed pERK but 5% of pERK expressing cells were negatively labelled for NK-1. It is concluded that a significant proportion of SRT cells projecting to the LRt respond to noxious mechanical stimuli and that one of the functions of this pathway may be to provide the cerebellum with nociceptive information.
authors.affiliation: Spinal Cord Group, Institute of Neuroscience and Psychology, College of Medicine, Veterinary Medicine and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK.
authors.forename: Zilli
authors.initials: Z
authors.lastname: Huma
authors.affiliation: Spinal Cord Group, Institute of Neuroscience and Psychology, College of Medicine, Veterinary Medicine and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK.
authors.forename: Kirsty
authors.initials: K
authors.lastname: Ireland
authors.affiliation: Spinal Cord Group, Institute of Neuroscience and Psychology, College of Medicine, Veterinary Medicine and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK. Electronic address: David.Maxwell@Glasgow.ac.uk.
authors.forename: David J
authors.initials: DJ
authors.lastname: Maxwell
mesh_terms: D000818:Animals; D002772:Cholera Toxin / Q000737:chemistry; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D008161:Lumbosacral Region; D008297:Male; D009474:Neurons / Q000378:metabolism*; D010146:Pain / Q000378:metabolism* / Q000503:physiopathology; D010766:Phosphorylation; D010812:Physical Stimulation; D017207:Rats, Sprague-Dawley; D012154:Reticular Formation / Q000378:metabolism* / Q000503:physiopathology; D013116:Spinal Cord / Q000378:metabolism; D020824:Spinocerebellar Tracts / Q000378:metabolism* / Q000503:physiopathology
chemical_list: D002772:Cholera Toxin; D048049:Extracellular Signal-Regulated MAP Kinases
keywords: ERK; Motor control; Neurokinin-1 receptor; Pain; Spinoreticular tract