Noxious colorectal distention induced-c-Fos protein in limbic brain structures in the rat

Immobility response elicited by clamping the neck induces antinociception in a “tonic pain” test in mice

“…There is a substantial body of evidence implicating the convergence of somatic and visceral inputs that occurs at the brainstem level. The results from animal stimulation, tracing studies, and human functional magnetic resonance imaging (Dunckley et al, 2005;Giesler and Liebeskind, 1976;Millan, 2002;Mönnikes et al, 2003;Rodella et al, 1998;Traub et al, 1996;Zhuo and Gebhart, 2002) demonstrate that the pattern of activation in areas as periaqueductal gray matter (PAG) and rostroventral medulla (RVM) is similar for the two sensory modalities, somatic and visceral. PAG and RVM nuclei are part of the nociceptive modulatory system (Millan, 2002).…”

Maternal separation as a model of brain–gut axis dysfunction

“…An increased level of c-fos-like immunoreactive nuclei have been found predominantly in the dorsal horn following CRD, with significantly more being present in separated animals (Ren et al 2007). This suggests that MS leads to the hyperactivation of neurons in the dorsal horn during CRD in response to descending influences originating in the brain stem (Traub et al 1996). More recently, we have shown that CRD induces a hyperresponsive c-fos activation in the amygdala and prefrontal cortex of MS animals compared to controls (Gibney et al 2009).…”

Visceral nociception

“…They have been shown to express the Fos protein after activation of visceral afferent nerve fibers in a variety of animal models [58]. Fos protein expression has also been shown to appear in the ventral reticular formation and the central nucleus of the amygdala after cyclophosphamide-induced inflammation of the bladder [59] and colorectal distension [60].…”