Diabetic neuropathy affects serotoninergic and Noradrenergic neurons at brainstem centers devoted to pain control

Abstract

Event Abstract Back to Event Diabetic neuropathy affects serotoninergic and Noradrenergic neurons at brainstem centers devoted to pain control Carla Morgado1*, Terra P. Pereira1, Fani L. Neto1 and Isaura Tavares1 1 IBMC-Instituto de Biologia Celular e Molecular, University of Porto, Institute of Histology and Embryology, Faculty of Medicine of Porto, Portugal Painful diabetic neuropathy is a common complication of diabetes which strongly affects the life quality of diabetic patients. Spinal cord and brain impairments were recently reported in humans and animals during painful diabetic neuropathy. Spinal neuronal hyperactivity observed in streptozotocin-diabetic rats (STZ rat) is probably a contributing factor for pain, but its causes remain unclear. It may result from increased peripheral input or local neurons hyperactivity but may also reflect impaired inhibitory descending modulation of spinal nociceptive transmission, which is mainly mediated by serotonin and noradrenaline. Here, we quantified the serotoninergic and noradrenergic neurons in the brainstem centres involved in descending pain control in STZ rats, by immunodetection of the synthesizing enzymes tryotophan hydroxilase (TpH) and tyrosine hydroxilase (TH), respectively.Male Wistar rats received an intraperitoneal injection of streptozotocin (STZ rats; 60 mg/kg) or saline (controls) and were sacrificed, under chloral hydrate anaesthesia, at 10 weeks post-injection (n= 5 rats per group). Upon vascular perfusion, brain sections were immunoreacted against TpH or TH, using the ABC method. Neurons immunoreactive neurons for TpH (TpH-IR) were counted in dorsal raphe nucleus (DRN), median raphe nucleus (MRN), caudal linear raphe (CLR), nucleus of the tractus solitarius (NTS), rostroventromedial medulla (RVM) and caudal ventrolateral medulla (CVLM). Neurons immunoreactive for TH (TH-IR) were counted in A1, A2, A5 and A7 noradrenergic cell groups. The numbers of TpH-IR neurons were significantly lower in STZ than in control rats at DRN (STZ: 29,6±3,82 vs control: 52,7±8,08; p<0,05), RVM (STZ: 4,9±1,71 vs control: 15,8±4,17; p<0,05) and CVLM (STZ: 1,8±0,28 vs control: 8,6±1,99; p<0,05). The A1 (STZ: 13,5±2,34 vs control: 19,2±0,50; p<0,05), A2 (STZ: 13,8±2,62 vs control: 35,6±3,40; p<0,01) and A5 (STZ: 9,8±0,73 vs control: 13,9±1,34; p<0,05) noragrenergic cell groups presented significant low numbers of TH-IR neurons in STZ than in control rats.These findings point to a deficient inhibitory descending modulation of spinal neurotransmission in STZ rats, which may contribute to spinal cord hyperactivity and concur to spontaneous pain during diabetes.Support by FCT project – PTDC/SAU/64643/2006. Conference: 11th Meeting of the Portuguese Society for Neuroscience, Braga, Portugal, 4 Jun - 6 Jun, 2009. Presentation Type: Oral Presentation Topic: Symposium 5 – Pain Citation: Morgado C, Pereira TP, Neto FL and Tavares I (2009). Diabetic neuropathy affects serotoninergic and Noradrenergic neurons at brainstem centers devoted to pain control. Front. Neurosci. Conference Abstract: 11th Meeting of the Portuguese Society for Neuroscience. doi: 10.3389/conf.neuro.01.2009.11.027 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 05 Aug 2009; Published Online: 05 Aug 2009. * Correspondence: Carla Morgado, IBMC-Instituto de Biologia Celular e Molecular, University of Porto, Institute of Histology and Embryology, Faculty of Medicine of Porto, Porto, Portugal, cmorgado@med.up.pt Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Carla Morgado Terra P Pereira Fani L Neto Isaura Tavares Google Carla Morgado Terra P Pereira Fani L Neto Isaura Tavares Google Scholar Carla Morgado Terra P Pereira Fani L Neto Isaura Tavares PubMed Carla Morgado Terra P Pereira Fani L Neto Isaura Tavares Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.