title: Alterations in intradental nerve responsiveness induced by electrical stimulation of the inferior alveolar nerve in the cat.
abstract: The effects of antidromic nerve stimulation on intradental nerve activity were studied by recording sensory nerve impulses from canine teeth in anaesthetized cats. Nerve responses to application of a solution of hypertonic sodium chloride (0.76 M) in dentinal cavities at various intervals before and after antidromic stimulation of the inferior alveolar nerve were compared. Low-intensity stimulation (2 V, 60 Hz, 0.02 ms) did not affect the nerve responses to subsequent applications of the hypertonic solution. In contrast, high-intensity stimulation (10 V, 10 Hz, 5 ms) induced biphasic changes in the intradental nerve activity, consisting of a transient, increased nerve response to sodium chloride during the first few minutes after stimulation, followed by a period (40 min) of decreased responses. Systemic pretreatment with phentolamine did not influence these effects, whereas after administration of mepyramine and cimetidine the nerve stimulation induced increased responses during a period of 50 min. Local application of substance P in dentinal cavities reduced the nerve responses to subsequent applications of hypertonic sodium chloride, thus mimicking the depressant effect of antidromic stimulation. This inhibitory effect of substance P was abolished by pretreatment with antihistamines. The present results show that electrical stimulation of the inferior alveolar nerve at intensities high enough to excite sensory C fibres alters the responsiveness of intradental nerves. Such changes probably reflect a neurogenic inflammatory-like reaction in the pulp, in which substance P and histamine take part.
mesh_terms: D000539:Alveolar Process / Q000294:innervation*; D000818:Animals; D002415:Cats; D002927:Cimetidine / Q000494:pharmacology; D003782:Dental Pulp / Q000294:innervation*; D004558:Electric Stimulation; D010646:Phentolamine / Q000494:pharmacology; D011738:Pyrilamine / Q000494:pharmacology; D012965:Sodium Chloride / Q000494:pharmacology; D013373:Substance P / Q000494:pharmacology; D014276:Trigeminal Nerve / Q000187:drug effects / Q000502:physiology*
chemical_list: D013373:Substance P; D012965:Sodium Chloride; D002927:Cimetidine; D011738:Pyrilamine; D010646:Phentolamine