RESUMO
Mechanosensitive (MS) neurons in the periodontal ligament (PDL) pass information to the trigeminal ganglion when excited by mechanical stimulation of the tooth. During occlusal tooth trauma of PDL tissues, MS neurons are injured, resulting in atrophic neurites and eventual degeneration of MS neurons. Nerve growth factor (NGF), a neurotrophic factor, serves important roles in the regeneration of injured sensory neurons. In the present study, the effect of proinflammatory cytokines, including interleukin 1ß (IL1ß) and tumor necrosis factor α (TNFα), on transforming growth factor ß1 (TGFß1)induced NGF expression was evaluated in rat PDLderived SCDC2 cells. It was observed that TGFß1 promoted NGF expression via Smad2/3 and p38 mitogenactivated protein kinase (MAPK) activation. IL1ß and TNFα suppressed the TGFß1induced activation of Smad2/3 and p38 MAPK, resulting in the abrogation of NGF expression. NGF secreted by TGFß1treated SCDC2 cells promoted neurite extension and the expression of tyrosine hydroxylase, a ratelimiting enzyme in dopamine synthesis in rat pheochromocytoma PC12 cells. These results suggested that proinflammatory cytokines suppressed the TGFßmediated expression of NGF in PDLderived fibroblasts through the inactivation of TGFßinduced Smad2/3 and p38 MAPK signaling, possibly resulting in the disturbance of the regeneration of injured PDL neurons.
Assuntos
Fibroblastos/metabolismo , Interleucina-1beta/farmacologia , Fator de Crescimento Neural/metabolismo , Ligamento Periodontal/citologia , Proteínas Smad/metabolismo , Fator de Crescimento Transformador beta/farmacologia , Fator de Necrose Tumoral alfa/farmacologia , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo , Trifosfato de Adenosina/análogos & derivados , Trifosfato de Adenosina/farmacologia , Animais , Fibroblastos/efeitos dos fármacos , Humanos , Fator de Crescimento Neural/genética , Neuritos/efeitos dos fármacos , Neuritos/metabolismo , Células PC12 , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Ratos , Receptores de Fatores de Crescimento Transformadores beta/metabolismo , Transdução de Sinais/efeitos dos fármacos , Tirosina 3-Mono-Oxigenase/metabolismoRESUMO
BACKGROUND: Although mepivacaine has a known biphasic action on the aortic and coronary artery in several animal species, its effects on the lingual and pulmonary artery are not well understood and it is not yet known whether mepivacaine produces vasoconstriction in these vessels. The present study aims to investigate the direct effects of mepivacaine on swine lingual, pulmonary and coronary arterial endothelium-denuded rings. METHODS: Artery rings were perfused with isotonic 40 mM KCl until a stable constricted plateau was reached. The rings were then perfused with isotonic 40 mM KCl plus a particular concentration of mepivacaine (0.4 µM, 4.0 µM, 40 µM, 0.4 mM and 4.0 mM). The isometric tension strengths in each experiment were normalized to the strength of the isometric tension immediately before mepivacaine perfusion and expressed as a percentage. RESULTS: Mepivacaine at 0.4 to 40 µM did not significantly alter 40 mM KCl-induced contraction in the lingual, pulmonary and coronary arterial rings. In contrast, mepivacaine at 4 mM produced attenuated vasoconstriction in the lingual, pulmonary and coronary arterial compared with isotonic 40 mM KCl. CONCLUSIONS: Mepivacaine produced vasoconstriction at lower concentrations, followed by attenuated vasoconstriction at higher concentrations on swine lingual, pulmonary and coronary arterial endothelium-denuded rings. Mepivacaine (4 µM) appeared to increase isotonic 40 mM KCl-induced contraction, followed by attenuated vasoconstriction at 4 mM. Dentists using 3 % mepivacaine should take into consideration that the risk of complications may be increased if more than six mepivacaine cartridges are used in dental treatment or minor surgery, or if over 15 ml of mepivacaine is administered to a patient with cardiovascular complications during general anesthesia for oral maxillofacial surgery.
Assuntos
Anestésicos Locais/farmacologia , Artérias/efeitos dos fármacos , Mepivacaína/farmacologia , Vasoconstrição/efeitos dos fármacos , Animais , Artérias/metabolismo , Vasos Coronários/efeitos dos fármacos , Vasos Coronários/metabolismo , Cloreto de Potássio/farmacologia , Artéria Pulmonar/efeitos dos fármacos , Artéria Pulmonar/metabolismo , Suínos , Língua/irrigação sanguíneaRESUMO
Local anesthesia may induce systemic complications leading to parasympathetic activity leading to bradycardia and hypotension. We report a case of a 50-year-old man undergoing dental surgery under general anesthesia who experienced severe bradycardia and hypotension after local anesthesia infiltration. Concerns regarding the utilization of a relatively large lumen injection needle for local anesthesia during general anesthesia are discussed.