title: Impact of tetrodotoxin application and lidocaine supplementation on equine jejunal smooth muscle contractility and activity of the enteric nervous system in vitro.
abstract: By blocking the enteric nervous system (ENS) using tetrodotoxin (TTX), previous studies have documented the contractility-enhancing (CE) effects of lidocaine in equine intestinal smooth muscle (SM) at the level of SM cells and/or interstitial cells of Cajal (ICC). The present study examined the impact of ENS deactivation on CE lidocaine effects, and investigated the effects of lidocaine on ENS activity. TTX application did not affect the CE effects of lidocaine, indicating that these were not mediated by TTX-sensitive sodium channels. Application of TTX or ≥100 mg/L lidocaine reduced ENS activity. Although such concentrations of lidocaine exceed therapeutic blood concentrations, tissue concentrations may be higher with the potential to reduce ENS activity and impair intestinal motility in vivo. Improved understanding of underlying mechanisms is relevant for therapeutic use of lidocaine in horses with postoperative ileus.
authors.affiliation: Department of Physiology, University of Veterinary Medicine, Bischofsholer Damm 15, D-30173 Hannover, Germany.
authors.forename: K
authors.initials: K
authors.lastname: Tappenbeck
authors.affiliation: Department of Physiology, University of Veterinary Medicine, Bischofsholer Damm 15, D-30173 Hannover, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Hoppe
authors.affiliation: Clinic for Horses, University of Veterinary Medicine, Bünteweg 9, D-30559 Hannover, Germany.
authors.forename: F
authors.initials: F
authors.lastname: Geburek
authors.affiliation: Clinic for Horses, University of Veterinary Medicine, Bünteweg 9, D-30559 Hannover, Germany.
authors.forename: K
authors.initials: K
authors.lastname: Feige
authors.affiliation: Department of Physiology, University of Veterinary Medicine, Bischofsholer Damm 15, D-30173 Hannover, Germany. Electronic address: korinna.huber@tiho-hannover.de.
authors.forename: K
authors.initials: K
authors.lastname: Huber
mesh_terms: D000818:Animals; D017615:Enteric Nervous System / Q000187:drug effects* / Q000502:physiology; D005769:Gastrointestinal Motility / Q000187:drug effects; D006736:Horses / Q000502:physiology*; D056885:Interstitial Cells of Cajal / Q000187:drug effects; D007583:Jejunum / Q000187:drug effects / Q000502:physiology; D008012:Lidocaine / Q000494:pharmacology*; D009119:Muscle Contraction / Q000187:drug effects*; D009130:Muscle, Smooth / Q000187:drug effects / Q000502:physiology; D026941:Sodium Channel Blockers / Q000494:pharmacology*; D013779:Tetrodotoxin / Q000494:pharmacology*; D061567:Voltage-Gated Sodium Channel Blockers / Q000494:pharmacology
chemical_list: D026941:Sodium Channel Blockers; D061567:Voltage-Gated Sodium Channel Blockers; D013779:Tetrodotoxin; D008012:Lidocaine
keywords: Enteric nervous system; Horse; Lidocaine; Motility; Small intestine