title: Mechanical nociceptive thresholds of dorsal laminae in horses after local anaesthesia of the palmar digital nerves or dorsal branches of the digital nerve.
abstract: We examined the hypothesis that the palmar digital nerves (PDNs), but not the dorsal branches (DBs) of the digital nerves, innervate the sensitive dorsal laminae of the equine foot by evaluating the effects of perineural anaesthesia of the PDNs and DBs separately on pain sensation evoked via mechanical stimulation of the dorsal laminae and other regions of the equine foot. Six clinically normal mares were used in a crossover design. A portable dynamometer was used to evaluate mechanical nociceptive thresholds at different points on the dorsal laminae, bulbs of the heel, coronary band and sole before and after the horses underwent perineural injection of PDNs or DBs with a local anaesthetic solution (treated group) or an isotonic saline solution (control group). Cornified tissue was removed from the sole and the dorsal aspect of the hoof wall before evaluations of mechanical nociceptive thresholds. Anaesthetising PDNs distal to the DBs increased mechanical nociceptive thresholds compared to baseline values (P <0.001) at sites assessed in the dorsal laminae, sole, and the bulbs of the heels. Anaesthetising DBs increased mechanical nociceptive thresholds compared to baseline values (P <0.01) only at sites assessed at the most proximal aspect of the foot (i.e., coronary band sites). In conclusion, PDNs, not DBs, are primarily responsible for pain signal transmission evoked by pressure in the dorsal laminae of the foot of clinically normal horses.
authors.affiliation: Department of Veterinary Clinics and Surgery, School of Veterinary, Universidade Federal de Minas Gerais, 6627 Av. Antônio Carlos, Belo Horizonte, MG 31270-901, Brazil.
authors.forename: C F R
authors.initials: CF
authors.lastname: Paz
authors.affiliation: Department of Veterinary Clinics and Surgery, School of Veterinary, Universidade Federal de Minas Gerais, 6627 Av. Antônio Carlos, Belo Horizonte, MG 31270-901, Brazil.
authors.forename: J F
authors.initials: JF
authors.lastname: Magalhães
authors.affiliation: Department of Veterinary Clinics and Surgery, School of Veterinary, Universidade Federal de Minas Gerais, 6627 Av. Antônio Carlos, Belo Horizonte, MG 31270-901, Brazil.
authors.forename: H M F
authors.initials: HM
authors.lastname: Mendes
authors.affiliation: Department of Veterinary Clinics and Surgery, School of Veterinary, Universidade Federal de Minas Gerais, 6627 Av. Antônio Carlos, Belo Horizonte, MG 31270-901, Brazil.
authors.forename: SdS
authors.initials: S
authors.lastname: Rocha Junior
authors.affiliation: Department of Veterinary Clinical Sciences, College of Veterinary Medicine, The Ohio State University, 601 Vernon Tharp St., Columbus, OH 43210, USA.
authors.forename: J K
authors.initials: JK
authors.lastname: Belknap
authors.affiliation: Department of Veterinary Clinics and Surgery, School of Veterinary, Universidade Federal de Minas Gerais, 6627 Av. Antônio Carlos, Belo Horizonte, MG 31270-901, Brazil.
authors.forename: G E S
authors.initials: GE
authors.lastname: Alves
authors.affiliation: Department of Veterinary Clinics and Surgery, School of Veterinary, Universidade Federal de Minas Gerais, 6627 Av. Antônio Carlos, Belo Horizonte, MG 31270-901, Brazil; Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Fellow, SHIS QI 1 Conjunto B - Blocos A, B, C e D Lago Sul, Brasília, DF 71605-001, Brazil. Electronic address: faleirosufmg@gmail.com.
authors.forename: R R
authors.initials: RR
authors.lastname: Faleiros
mesh_terms: D000772:Anesthesia, Local / Q000662:veterinary; D000779:Anesthetics, Local / Q000008:administration & dosage*; D000818:Animals; D018592:Cross-Over Studies; D005260:Female; D005528:Foot / Q000502:physiology; D006724:Hoof and Claw / Q000294:innervation*; D006736:Horses / Q000502:physiology*; D059225:Nociception / Q000187:drug effects*; D010146:Pain / Q000662:veterinary*; D010525:Peripheral Nerves / Q000502:physiology*
chemical_list: D000779:Anesthetics, Local
keywords: Diagnostic analgesia; Equine; Foot; Lameness; Pain