Effects of BP 2-94, a selective H(3)-receptor agonist, on blood flow and vascular permeability of the rat mandibular incisor pulp.
Pulpal blood-flow changes were monitored by laser Doppler flowmetry after electrical stimulation of the mandibular incisor. Stimuli of 10 s (50 microA, 2 ms, 20 Hz) were applied to the incisors of untreated animals and longer stimulations (5 min) were applied in animals treated with the alpha-blocker phenoxybenzamine. Changes in vascular permeability in the dental pulp were measured by Evans blue extravasation following resection of the superior cervical ganglion. In these groups, a selective agonist of H(3) receptors, BP2-94 (1.5 and 15 mg/kg), and an H(3)-antagonist ciproxifan (1 mg/kg) were administered. The effects of these drugs were compared with those obtained from animals treated only with the vehicle (methylcellulose 1%). Basal pulpal blood-flow was not affected significantly by BP2-94 or ciproxifan. The vasoconstriction induced in the group of intact rats by electrical stimulation of 10 s is decreased in amplitude and duration at the higher dose of BP2-94 by 58 and 40%, respectively (P<0.05, n=5). In the sympathectomized animals, plasma extravasation was significantly increased at 15 mg/kg BP2-94 (+100%, P<0.01, n=5). These results suggest that H(3) receptors may participate in the regulation of changes in vessel contraction and permeability provoked by electrical stimulation of the dental pulp. However, the non-selective effects of the H(3) agonists reacting on adrenergic sites and H(1) receptors could explain a part of the results.
Boucher
Y
Y
Laboratoire de Physiologie de la Manducation, 2 Place Jussieu Bat A, 2ème étage, 75252 Paris, France. ybou@ccr.jussieu.fr
Hofman
S
S
Joulin
Y
Y
Azérad
J
J
D000818:Animals; D002199:Capillary Permeability / Q000187:drug effects*; D004396:Coloring Agents; D003782:Dental Pulp / Q000098:blood supply*; D004558:Electric Stimulation; D005070:Evans Blue; D005119:Extravasation of Diagnostic and Therapeutic Materials; D017442:Histamine Agonists / Q000494:pharmacology*; D006633:Histamine Antagonists / Q000494:pharmacology; D007093:Imidazoles / Q000494:pharmacology; D007097:Imines / Q000494:pharmacology*; D017078:Laser-Doppler Flowmetry; D008334:Mandible; D008833:Microcirculation / Q000187:drug effects; D010636:Phenols / Q000494:pharmacology*; D011355:Prodrugs / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012039:Regional Blood Flow / Q000187:drug effects; D013562:Sympathectomy; D014666:Vasomotor System / Q000187:drug effects / Q000502:physiology
D004396:Coloring Agents; D017442:Histamine Agonists; D006633:Histamine Antagonists; D007093:Imidazoles; D007097:Imines; D010636:Phenols; D011355:Prodrugs; C106714:BP 2-94; D005070:Evans Blue; C115705:ciproxifan