ABSTRACT
Vasodilation, an important response in neurogenic inflammation, involves release of Substance P (SP) from the sensory nerve endings. It is now well known that SP causes edema formation and vascular relaxation in nondental tissues, however, the SP vasodilatory mechanism in the dental pulp is not completely understood. Endothelium-dependent relaxation is mediated by nitric oxide (NO) release with consecutive intracellular cyclic-GMP elevation in many vascular preparations. Recently, it has been shown in different vascular systems that SP-induced vasodilation is mediated by cyclic-GMP production through different pathways involving endothelial NO or direct endothelial-independent pathways. In the present study, the role of endothelial NO in SP induced vasodilation in the dental pulp was investigated to better understand the inflammatory mechanisms. Freshly extracted bovine dental pulp was used to measure NO production. Sodium nitroprusside (SNP), L-NAME and SP were utilized to induce and to inhibit NO production in endothelial cells. Released NO byproducts were measured with chemiluminescence assay technique. The present data demonstrate that SP induces NO production by activating NOsynthase (NOS) in endothelial cells. The NOS inhibitor L-NAME blocks NO production completely. In conclusion, in the bovine dental pulp, SP-induced vascular relaxation can be mediated by inducing NOS, and subsequently NO production in endothelial cells.
Subject(s)
Dental Pulp/blood supply , Neurogenic Inflammation/physiopathology , Nitric Oxide/physiology , Substance P/pharmacology , Vasodilation/drug effects , Vasodilator Agents/pharmacology , Analysis of Variance , Animals , Cattle , Endothelium, Vascular/drug effects , Endothelium, Vascular/enzymology , Enzyme Activation , Enzyme Inhibitors/pharmacology , Muscle, Smooth, Vascular/drug effects , NG-Nitroarginine Methyl Ester/pharmacology , Nitric Oxide/biosynthesis , Nitric Oxide Donors/pharmacology , Nitric Oxide Synthase/antagonists & inhibitors , Nitric Oxide Synthase/metabolism , Nitroprusside/pharmacology , Pulpitis/enzymologyABSTRACT
The idea of the hybrid concept is to combine instruments of different file systems and use different instrumentation techniques to manage individual clinical situations to achieve the best biomechanical cleaning and shaping results and the least procedural errors. The hybrid concept combines the best features of different systems for safe, quick, and predictable results. Several hybrid instrumentation sequences are presented and their limitations are discussed.
