Effects of ethanol on deep pain evoked by formalin injected in TMJ of rat

A novel method for subarachnoid drug delivery in the medullary region of rats

“…The magnitude of nociceptive behavior induced by the TMJ injection of formalin was similar to that of previous studies (Roveroni et al, 2001;Gameiro et al, 2003;Clemente et al, 2004). Morphine injection into subarachnoid space of the medullary region produced a dose-dependent suppression of the formalin-induced nociceptive behavior (Fig.…”

“…Second, for the same reason, it does not require that rats be housed singly, a situation that results in the appearance of a social isolation syndrome (Hatch et al, 1965), which may affect nociceptive responses and behavioral test reliability (Jasmin and Ohara, 2001). Third, it is minimally invasive and may be combined with many models of orofacial pain (Vos et al, 1994;Clavelou et al, 1995;Roveroni et al, 2001;Chidiac et al, 2002;Hartwig et al, 2003;Ogawa et al, 2003), particularly with the orofacial behavioral pain models in which head flinch or head withdraw is evaluated (Anderson and Rao, 2001;Christensen et al, 2001;Imbe et al, 2001;Roveroni et al, 2001;Benoliel et al, 2002a;Gameiro et al, 2003;Hartwig et al, 2003;Ogawa et al, 2003;Clemente et al, 2004). In contrast, the conventional catheterization methods for medullary drug delivery (Aigouy et al, 1992;Flores et al, 2001;Tambeli et al, 2001;Wang et al, 2002) require surgical exposition of neck muscles, and implies freeing these muscles from the occipital crest to allow the catheter implantation.…”

“…studies is essential in elucidating the underlying mechanisms of pathophysiology of orofacial pain syndromes and temporomandibular disorders. However, the surgical catheter implantation performed to study the effect of drugs delivered in the medullary dorsal horn region may affect some of the frequently used nociceptive behavioral measures that require normal neck muscle activity to occur, such as head withdraw in response to a local mechanical stimulus (Anderson and Rao, 2001;Christensen et al, 2001;Imbe et al, 2001;Benoliel et al, 2002b;Ogawa et al, 2003), or head flinch induced by local chemical stimulation (Anderson and Rao, 2001;Roveroni et al, 2001;Chidiac et al, 2002;Gameiro et al, 2003;Hartwig et al, 2003;Clemente et al, 2004). Therefore, the aim of this study was to develop a method for direct subarachnoid drug delivery to the medullary region that facilitates animal investigation of orofacial pain, and that can be combined with many orofacial pain models, particularly with those that use nociceptive behavior measures, such as head flinch or head withdraw.…”

Peripheral effect of a kappa opioid receptor antagonist on nociception evoked by formalin injected in TMJ of pregnant rats

“…Considering that the head flinching behavior followed a uniform pattern of lasting for 1 s, each flinching was expressed as 1 s. The sum of both behaviors provides a better measure of pain intensity than any single behavior (Roveroni et al, 2001;Gameiro et al, 2003). An investigator, who was blind to the rat's group assignment, did the behavior analysis.…”

Involvement of peripheral TRPV1 in TMJ hyperalgesia induced by ethanol withdrawal

“…There is evidence that behavioral hyperalgesia can be induced after the suspension of chronic ethanol administration (Gatch, 1999(Gatch, , 2002Gatch and Lal, 1999;Gatch and Selvig, 2002;Gameiro et al, 2003), but the neurological basis for hyperalgesia induced by ethanol withdrawal is not fully explained. Trevisani et al (2002) reported that ethanol mediated the modulation of vanilloid receptor type 1 (TRPV1) function.…”