Morphological characteristics of primary sensory and post-synaptic sympathetic neurones supplying the temporomandibular joint in the cat

Nerve growth factor acts with the β2-adrenoceptor to induce spontaneous nociceptive behavior during temporomandibular joint inflammatory hyperalgesia

“…It is well known that inflammatory pain has a sympathetic component (Levine et al, 1986;Nakamura and Ferreira, 1987) that may predominate in pain less sensitive to non-steroidal antiinflammatory drugs and in regions receiving rich sympathetic innervation, such as the TMJ (Widenfalk and Wiberg, 1990;Yoshino et al, 1998;Ta and Dionne, 2004). We observed here that TMJ coinjection of carrageenan with ICI 118.55 but not with atenolol significantly reduced NGF-induced spontaneous nociceptive behavior, indicating the cooperation between NGF and the sympathetic system acting through β2 adrenergic receptor activation in the TMJ inflammatory hyperalgesia.…”

Convergence of nociceptive information from temporomandibular joint and tooth pulp afferents on C1 spinal neurons in the rat

“…The rat trigeminal ganglion projects centrally to both the trigeminal nuclear complex and cervical dorsal horn (Jacquin et al, 1983;Pfaller and Arvidsson, 1988), and vagal afferent fibers project directly to the upper cervical segments of the spinal cord via a supraspinal route from the nodose ganglia (McNeill et al, 1991). In the studies with retrograde axonal tracers, the TMJ region is supplied with nerve fibers, originating mainly in the trigeminal ganglion, in addition to other sensory and sympathetic ganglia (Widenfalk and Wiberg, 1990;Uddman et al, 1999), and consisting of both myelinated (Ay) and unmyelinated (C) fibers (Yoshino et al, 1998).…”

5-HT induces temporomandibular joint nociception in rats through the local release of inflammatory mediators and activation of local β adrenoceptors

“…This result suggests that 5-HT-induced nociception is mediated by the peripheral release of norepinephrine, but the mechanism underlying the release is not known. However, it has been demonstrated that the TMJ is densely innervated by sympathetic fibers arising from cells of the superior cervical ganglion (Kido et al, 2001;Widenfalk and Wiberg, 1990;Yoshino et al, 1998) that express 5-HT 3 receptors (Morales and Wang, 2002;Rosenberg et al, 1997;Yang et al, 1992). Therefore, the activation of 5-HT 3 receptors expressed on the sympathetic terminals located in the TMJ may result in the vesicular release of norepinephrine which may act on β 1and β 2 -adrenoreceptors of the TMJ to contribute to 5-HT induced TMJ nociception.…”