Involvement of afferent nerves in pulpal blood-flow reactions in response to clinical and experimental procedures in the cat.
A unilateral resection of the mandibular nerve (n = 20) was made 10-14 days before investigation of the contribution of afferent nerves in vasodilator reactions in the dental pulp. Lower canine teeth were subjected to various stimuli and pulp blood-flow responses monitored by laser Doppler flowmetry. An absence of response to bipolar electrical (5 impulses, 50 microA, 5 ms, 2 Hz) stimulation on the tooth surface was used to demonstrate a successful chronic nerve lesion. Local application of capsaicin (10(-4) M) in a deep dentinal cavity induced a long-lasting increase in pulpal blood flow in control teeth only. Bradykinin (10(-3) M) induced significantly larger responses in control than in denervated teeth (58.3 +/- 9.8% and 24.5 +/- 4.9%, respectively, p less than 0.005, n = 8); in addition, the onset was slower and the duration of the response significantly (60%) shorter than in control teeth. Intermittent grinding of surface dentine instantly increased flow in control teeth by 53.0 +/- 12.5% (n = 12) whereas in denervated teeth the response was delayed and significantly (70%) smaller. Deeper preparation produced responses of similar magnitude in control and denervated teeth (69 and 50%, respectively) but the onset was delayed in denervated teeth. Low-intensity ultrasonic stimulation caused vasodilation in intact teeth (38% increase) but had no effect in denervated teeth. This effect was abolished after local anaesthetic (mepivacaine) injection. Sympathectomy (n = 3) did not influence stimulation-induced blood-flow responses in the dental pulp.(ABSTRACT TRUNCATED AT 250 WORDS)
Olgart
L
L
Department of Pharmacology, Karolinska Institute, Stockholm, Sweden.
Edwall
L
L
Gazelius
B
B
D000287:Administration, Topical; D000818:Animals; D001920:Bradykinin / Q000008:administration & dosage / Q000494:pharmacology; D002211:Capsaicin / Q000008:administration & dosage / Q000494:pharmacology; D002415:Cats; D003737:Dental Cavity Preparation; D003782:Dental Pulp / Q000098:blood supply* / Q000187:drug effects / Q000294:innervation; D004558:Electric Stimulation; D005728:Ganglia, Sympathetic / Q000502:physiology / Q000601:surgery; D007275:Injections, Intravenous; D007834:Lasers; D008297:Male; D008340:Mandibular Nerve / Q000502:physiology / Q000601:surgery; D009475:Neurons, Afferent / Q000187:drug effects / Q000502:physiology*; D010474:Percussion; D012039:Regional Blood Flow / Q000187:drug effects / Q000502:physiology; D013373:Substance P / Q000008:administration & dosage / Q000494:pharmacology; D014070:Tooth / Q000294:innervation*
D013373:Substance P; D002211:Capsaicin; D001920:Bradykinin