HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: 569/2/617    most recent jphysiol.2005.087643v1 Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Ishii, H. Articles by Izumi, H. Search for Related Content PubMed PubMed Citation Articles by Ishii, H. Articles by Izumi, H.

Departments of
¹ Oral Physiology
² Removable Prosthodontics, School of Dentistry, Health Sciences University of Hokkaido, Ishikari-Tobetsu, Hokkaido 061-0293, Japan

The present study was designed to examine (1) whether there are vasodilator fibres in the masseter muscle, and (2) if there are, to establish the neural pathways mediating these responses in urethane-anaesthetized rats. Electrical stimulation of the central cut end of the lingual nerve (LN) elicited intensity- and frequency-dependent increases of the blood flow in the masseter muscle (MBF) and lower lip (LBF). Increases in both the MBF and LBF evoked by the LN stimulation were reduced by hexamethonium in a dose-dependent manner (1–10 mg kg^–1). Pretreatment with phentolamine or propranolol at a dose of 100 µg kg^–1 had no effect on the increases in either MBF or LBF evoked by LN stimulation. Pretreatment with atropine (100 µg kg^–1) significantly reduced the MBF increase induced by LN stimulation, but not that in the LBF. The sectioning of the superior cervical sympathetic trunk did not affect the responses. MBF increases occurred with electrical stimulation of the trigeminal ganglion, and these increases were significantly reduced by the administration of hexamethonium and atropine. Lidocaine microinjection into the trigeminal spinal nucleus or salivatory nuclei caused a significant attenuation of the LN-induced MBF increases. When wheat germ agglutinin–horseradish peroxidase (WGA–HRP) was injected into the masseter muscle, labelled neurones were abundantly observed in the otic ganglion. The present study indicates that there are parasympathetic cholinergic and noncholinergic vasodilator fibres originating from cell bodies in the otic ganglion in the rat masseter muscle. The MBF increase evoked by activation of the parasympathetic fibres occurred via the trigeminal mediated reflex, suggesting that the novel parasympathetic vasodilator response may play an important role in the regulation of the haemodynamics of jaw muscles.

(Received 11 April 2005; accepted after revision 25 July 2005; first published online 28 July 2005)
Corresponding author H. Izumi: Health Sciences University of Hokkaido, 1757 Kanazawa, Ishikari-Tobetsu, Hokkaido 061-0293, Japan. Email: izumih{at}hoku-iryo-u.ac.jp

This article has been cited by other articles:

				H. Ishii, T. Niioka, H. Watanabe, and H. Izumi Inhibitory effects of excess sympathetic activity on parasympathetic vasodilation in the rat masseter muscle Am J Physiol Regulatory Integrative Comp Physiol, August 1, 2007; 293(2): R729 - R736. [Abstract] [Full Text] [PDF]