title: TRPV1 properties in thoracic dorsal root ganglia neurons are modulated by intraperitoneal capsaicin administration in the late phase of type-1 autoimmune diabetes.
abstract: Pharmacological therapies in type 1 diabetes for efficient control of glycemia and changes in pain alterations due to diabetic neuropathy are a continuous challenge. Transient receptor potential vanilloid type 1 (TRPV1) from dorsal root ganglia (DRG) neurons is one of the main pharmacological targets in diabetes, and its ligand capsaicin can be a promising compound for blood-glucose control. Our goal is to elucidate the effect of intraperitoneal (i.p.) capsaicin administration in type 1 diabetic mice against TRPV1 receptors from pancreatic DRG primary afferent neurons. A TCR(+/-)/Ins-HA(+/-) diabetic mice (dTg) was used, and patch-clamp and immunofluorescence microscopy measurements have been performed on thoracic T(9)-T(12) DRG neurons. Capsaicin (800 μg/kg, i.p. three successive days) administration in the late-phase diabetes reduces blood-glucose levels, partly reverses the TRPV1 current density and recovery time constant, without any effect on TRPV1 expression general pattern, in dTg mice. A TRPV1 hypoalgesia profile was observed in late-phase diabetes, which was partly reversed to normoalgesic profile upon capsaicin i.p. administration. According to the soma dimensions of the thoracic DRG neurons, a detailed analysis of the TRPV1 expression upon capsaicin i.p. treatment was done, and the proportion of large A-fiber neurons expressing TRPV1 increased in dTg capsaicin-treated mice. In conclusion, the benefits of low-dose capsaicin intraperitoneal treatment in late-phase type-1 diabetes should be further exploited.
authors.affiliation: Department of Neurological, Neuropsychological, Morphological and Movement Sciences, Faculty of Medicine, University of Verona, Verona, Italy.
authors.forename: Beatrice Mihaela
authors.initials: BM
authors.lastname: Radu
authors.forename: Adina Daniela
authors.initials: AD
authors.lastname: Iancu
authors.forename: Diana Ionela
authors.initials: DI
authors.lastname: Dumitrescu
authors.forename: Maria Luisa
authors.initials: ML
authors.lastname: Flonta
authors.forename: Mihai
authors.initials: M
authors.lastname: Radu
mesh_terms: D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D002211:Capsaicin / Q000008:administration & dosage* / Q000494:pharmacology / Q000627:therapeutic use*; D002478:Cells, Cultured; D003922:Diabetes Mellitus, Type 1 / Q000097:blood / Q000150:complications / Q000188:drug therapy*; D005455:Fluorescent Antibody Technique; D005727:Ganglia, Spinal / Q000187:drug effects / Q000378:metabolism / Q000473:pathology*; D006943:Hyperglycemia / Q000097:blood / Q000150:complications / Q000188:drug therapy; D007274:Injections, Intraperitoneal; D015640:Ion Channel Gating / Q000187:drug effects; D051379:Mice; D008807:Mice, Inbred BALB C; D008822:Mice, Transgenic; D011984:Sensory Receptor Cells / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D050916:TRPV Cation Channels / Q000378:metabolism*; D013909:Thorax / Q000294:innervation*
chemical_list: D001786:Blood Glucose; D050916:TRPV Cation Channels; C493921:TRPV1 protein, mouse; D002211:Capsaicin