title: The blocking effect of iontophoretic administration of lidocaine on neurogenic vascular reactions in rat dental pulp.
abstract: The blocking effect of lidocaine on nerve-induced vascular reactions was investigated in lower incisor teeth of anaesthetized rats. Pulpal blood flow was measured with laser Doppler flowmetry. Monopolar electrical stimulation of the rat incisor evoked a biphasic vascular response: an initial vasoconstriction was followed by a long-lasting vasodilation. Iontophoresis of lidocaine on a superficially exposed dentin surface with 60 microA of anodal direct current for 20 min blocked almost completely the stimulus-induced blood flow increase for about 25 min without any systemic effects. Iontophoresis of lidocaine with 40 microA for 20 min was almost without effect. Topical application of a mixture of lidocaine and prilocaine (25 + 25 mg/ml) in deep dentinal cavities was also without effect on the neurogenic reactions. Intravenous administration of lidocaine at 5 and 10 mg/kg in rats pretreated with phenoxybenzamine reduced the stimulus-induced increase in blood flow by an average of 29% and 54%, respectively, whereas the remaining alpha-adrenoceptor resistant vasoconstriction was not influenced. The present results show that iontophoresis of lidocaine on exposed dentin blocks nerve-induced vascular responses without causing systemic effects.
authors.affiliation: Department of Physiology and Pharmacology, Karolinska Institute, Stockholm, Sweden.
authors.forename: G D
authors.initials: GD
authors.lastname: Kostouros
authors.forename: L
authors.initials: L
authors.lastname: Olgart
authors.forename: L
authors.initials: L
authors.lastname: Edwall
mesh_terms: D000779:Anesthetics, Local / Q000008:administration & dosage*; D000818:Animals; D003782:Dental Pulp / Q000098:blood supply* / Q000294:innervation; D003806:Dentin Permeability; D007478:Iontophoresis / Q000379:methods*; D017078:Laser-Doppler Flowmetry; D008012:Lidocaine / Q000008:administration & dosage*; D008297:Male; D011311:Pressoreceptors / Q000187:drug effects*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012039:Regional Blood Flow; D009435:Synaptic Transmission / Q000187:drug effects
chemical_list: D000779:Anesthetics, Local; D008012:Lidocaine