Effects of excitatory amino acid receptor antagonists on pulpal blood flow of the rat mandibular incisor.
Pulpal blood flow (PBF) changes have been monitored by laser Doppler flowmetry on rat mandibular incisors. Electrical stimulation (10 sec, 50 microA, 2 ms, 20 Hz) of one incisor induced a blood flow decrease followed by a blood flow increase. The effect of intravenous administration of antagonists of ionotropic glutamate receptors (iGluRs) and antagonists of metabotropic glutamate receptors (mGluRs) was compared with that of those obtained from animals treated with the vehicle alone. No long-term effect on basal PBF was observed, except a remaining increase of 34.5% (p < 0.05, n = 5) for ketamine (10 mg/kg), an iGluR antagonist, and of 37% (p < 0.05, n = 5) for MCPG (7.5 mg/kg), an mGluR antagonist. In animals treated with iGluR antagonists, acute changes in PBF after stimulation were not significantly different from those observed with vehicle. In animals treated with mGluR antagonists, the blood flow decrease was significantly enhanced in amplitude and duration for MCPG (7.5 mg/kg), respectively, +73% and +92% (p < 0.05, n = 5). These results suggest that Group I mGluRs participate in the regulation of the immediate pulpal blood flow decrease induced by electrical stimulation of the lower incisor in the rat.
Hofman
S
S
Laboratoire de Physiologie de la Manducation, Université Paris 7-Denis Diderot, 2 Place Jussieu, Bât. A, France. hofman@ccr.jussieu.fr
Azérad
J
J
Boucher
Y
Y
D000704:Analysis of Variance; D000818:Animals; D001810:Blood Volume / Q000187:drug effects; D003782:Dental Pulp / Q000098:blood supply* / Q000294:innervation; D004558:Electric Stimulation; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology*; D007180:Incisor; D017078:Laser-Doppler Flowmetry; D008297:Male; D008334:Mandible; D008833:Microcirculation / Q000187:drug effects*; D051381:Rats; D017207:Rats, Sprague-Dawley
D018691:Excitatory Amino Acid Antagonists