Dorsal column lesions reverse the reduction of homecage activity in rats with pancreatitis

Abstract

A midline dorsal column (DC) lesion has been shown to be an effective surgical treatment for the relief of pelvic visceral pain in patients. The aim of this study was to examine the effectiveness of a DC lesion for the relief of pancreatitis pain in awake rats. Homecage activity was measured in rats with pancreatitis or sham surgery. Pancreatitis was induced by infusion of glycodeoxycholic acid (10 mM) into the pancreas and intraperitoneal injection of caerulian (72 microg). Homecage activity was also measured in rats with pancreatitis after either a DC lesion of the C1 level of the spinal cord or a sham DC lesion. A significant reduction in rearing behavior was observed in rats with pancreatitis when compared to sham animals. DC lesions reversed this reduction in rearing activity. This study suggests that the DCs are involved in transmitting nociceptive signals from the pancreas to the brain.

Ablation of sensory neurons in a genetic model of pancreatic ductal adenocarcinoma slows initiation and progression of cancer

“…Although at the early PanIN stage the pancreas does not exhibit major inflammation, astrocyte activation in the spinal cord was equivalent to that seen in response to acute pancreatitis. The activation of spinal cord glia affected all regions of the white matter although pancreatic sensory fibers run primarily in the dorsal columns (60)(61)(62)(63) and anterolateral regions of the spinal cord (64). In patients with pancreatic cancer, peripheral nerve damage associated with PNI has been linked to spinal cord glial activation in T10-L1 (65).…”

Restoration of spontaneous exploratory behaviors with an intrathecal NMDA receptor antagonist or a PKC inhibitor in rats with acute pancreatitis

“…The discomfort, decreased exploratory activity, and increased spontaneous pain-related behaviors following inflammation of the pancreas (or other visceral organs) reflect secondary hyperalgesia resulting from the positive feedback of central visceral nociceptive amplification processes (Coutinho et al, 1996;Houghton et al, 1997;Mayer and Gebhart, 1994).…”

“…In order to speed up the contraction of the bile system, caerulein (Sigma), a CCK analogue, was injected intraperitoneally (Houghton et al, 1997). Rats were anesthetized with sodium pentobarbital (50 mg/kg ip).…”

“…Changes in activity may not be reflected by a single parameter; therefore, each of the six parameters was evaluated. Since most activities occurred within the first 5 min following introduction of the rat into the novel environment, changes in activity were evaluated during the first 5-min interval and compared among different groups (Houghton et al, 1997;Mills et al, 2001). …”

“…To assess visceral nociception in an acute pancreatitis animal model, an automated photobeam activity system was used to measure animal exploratory activity. An assessment of exploratory activity as a measure of spontaneous pain has been used in other studies such as formalin-induced pain models (Aloisi et al, 1995), arthritic models of chronic pain (Larsen and Arnt, 1985), chronic central pain following spinal cord injury (Mills et al, 2001), and in visceral pain models (Houghton et al, 1997;Palecek et al, 2002).…”