ABSTRACT
Orofacial pain is associated with peripheral and central sensitization of trigeminal nociceptive neurons. Nerve injury results in release of chemical mediators that contribute to persistent pain conditions. The activation of the transient receptor potential vanilloid 1 (TRPV1), promotes release of calcitonin gene-related peptide (CGRP) and substance P (SP) from trigeminal nerve terminals. CGRP and SP contribute to the development of peripheral hyperalgesia. The expression of SP and CGRP by primary afferent neurons is rapidly increased in response to peripheral inflammation. CGRP receptor activation promotes activation of AMPA receptors, leading to increased firing of neurons which is reflected as central sensitization. In this study we investigated whether inferior alveolar nerve (IAN) injury influences AMPA receptors, CGRP, SP and TRPV1 expression in the trigeminal ganglion (TG). The relative expression of the protein of interest from naive rats was compared to those from injured rats and animals that received low level laser therapy (LLLT). IAN-injury did not change expression of GluA1, GluA2 and CGRP, but increased the expression of TRPV1 and SP. LLLT increases GluA1 and GluA2 expression and decreases TVPV1, SP and CGRP. These results, together with previous behavioral data, suggest that IAN-injury induced changes in the proteins analyzed, which could impact on nociceptive threshold. These data may help to understand the molecular mechanisms of pain sensitization in the TG.
Subject(s)
Facial Nerve Injuries/radiotherapy , Gene Expression Regulation/radiation effects , Low-Level Light Therapy , Mandibular Nerve/radiation effects , Trigeminal Ganglion/radiation effects , Animals , Calcitonin Gene-Related Peptide/genetics , Calcitonin Gene-Related Peptide/metabolism , Facial Nerve Injuries/genetics , Facial Nerve Injuries/metabolism , Facial Nerve Injuries/pathology , Male , Mandibular Nerve/metabolism , Mandibular Nerve/pathology , Neurons, Afferent/metabolism , Neurons, Afferent/pathology , Neurons, Afferent/radiation effects , Photic Stimulation/methods , Rats , Rats, Sprague-Dawley , Receptors, AMPA/genetics , Receptors, AMPA/metabolism , Signal Transduction , Substance P/genetics , Substance P/metabolism , TRPV Cation Channels/genetics , TRPV Cation Channels/metabolism , Trigeminal Ganglion/injuries , Trigeminal Ganglion/metabolismABSTRACT
Considerado uno de los dolores más intensos que puede soportar el ser humano, la neuralgia trigeminal ha sido tratada con innumerables métodos. Entre ellos, los percutáneos surgieron como variantes poco agresivas e igualmente eficaces que aquellos métodos a cielo abierto. El más reciente de los métodos percutáneos: la compresión de las fibras del ganglio trigeminal de Gasser, se utiliza en el Servicio de Neurocirugía del Hospital Universitario "General Calixto García", guiado por radiología simple(AU)
Considered one of the most intense pains that the human being, the neuralgia trigeminal can support has been treated with countless methods. Among them, the percutáneos arose as not very aggressive and equally effective variants that those methods to open sky. The most recent in the methods percutáneos: the compression of the fibers of the ganglion trigeminal of Gasser, is used in the Service of Neurosurgery of the General University Hospital Calixto García", guided by simple radiology(AU)