title: Increased blood flow and nerve firing in the cat canine tooth in response to stimulation of the second premolar pulp.
abstract: Mustard oil or mechanical stimulation was applied to maxillary second premolar tooth pulps and pulpal blood flow and or intradental nerve activity in the ipsilateral canine tooth were recorded in the cat. Mustard oil application to the second premolar pulp significantly increased blood flow in the canine tooth pulp to 162.0+/-65.8% (n = 16) of the prestimulation flow compared to control data obtained with application of mineral oil (107.0+/-5.1%, n = 6) (Mann-Whitney U-test, p = 0.0009). Sectioning of the infraorbital nerve and its branches on the experimental side (n = 4) did not affect this increase in pulpal blood flow. The paraperiosteal injection of 2% lidocaine (1.0 ml) without vasoconstrictor significantly inhibited the increase in canine pulpal blood flow induced by mustard oil application to the second premolar pulp (109.8+/-6.8% of the prestimulation level, n = 7) (Mann-Whitney U-test, p = 0.0013). Sporadic firing or sometimes bursts of action potentials in the canine pulp nerves were recorded during and/or after the mustard oil application to the second premolar pulp in three of 16 cases. Four single pulp nerve units firing in synchrony with the mechanical stimulation of the second premolar pulp were recorded in two of eight canines, which substantiated the existence of branched afferents innervating both teeth. These findings suggest that stimulation of the second premolar pulp may induce axon reflex-related vasodilation and intradental nerve firing in the canine pulp via branched afferent fibres innervating both the second premolar and canine teeth.
authors.affiliation: Department of Endodontics, Faculty of Dentistry, Tokyo Medical and Dental University, Japan. a.hikiji.endo@dent.tmd.ac.jp
authors.forename: A
authors.initials: A
authors.lastname: Hikiji
authors.forename: H
authors.initials: H
authors.lastname: Yamamoto
authors.forename: M
authors.initials: M
authors.lastname: Sunakawa
authors.forename: H
authors.initials: H
authors.lastname: Suda
mesh_terms: D000818:Animals; D001641:Bicuspid / Q000187:drug effects / Q000502:physiology*; D001783:Blood Flow Velocity / Q000187:drug effects; D002415:Cats; D003481:Cuspid / Q000098:blood supply* / Q000187:drug effects / Q000294:innervation*; D003782:Dental Pulp / Q000187:drug effects / Q000502:physiology*; D017078:Laser-Doppler Flowmetry; D009149:Mustard Plant; D009424:Nervous System Physiological Phenomena / Q000187:drug effects; D010812:Physical Stimulation; D010936:Plant Extracts / Q000494:pharmacology; D010938:Plant Oils
chemical_list: D010936:Plant Extracts; D010938:Plant Oils; C027793:mustard oil