Gastric dysmotility after abdominal surgery in persons with cervical spinal cord injury: a case series

Regulation of gastric motility and blood flow during acute nociceptive stimulation of the paraspinal muscles in urethane-anaesthetised rats

The aim of this study was to examine gastric motility and blood flow during nociceptive hypertonic saline injections (HS) in paraspinal muscles of urethane-anaesthetised rats. Gastric pressure was not affected by HS in intact or vagotomised conditions. After cervical spinalisation, it was decreased by injections at T13 or L6 but not T2. Moreover, HS injections at T13 produced greater gastric pressure decreases compared with L6 and T2 and increased gastric sympathetic nerve activity. Blood pressure and gastric blood flow were decreased by T13 injections in spinal cord intact but not spinalised rats. Besides, isotonic saline injections (non-nociceptive) produced non-significant or marginal effects. These results indicate that gastric motility is decreased by nociceptive input from paraspinal muscles in spinalised rats through activation of the gastric sympathetic nerve. Although gastric blood flow was also decreased by nociceptive stimulation at T13 in spinal cord intact rats, these changes seem to depend on blood pressure.

Pain without nociception?

We describe a young woman with complete cervical spinal cord transsection, who developed significant abdominal pain, triggered by gastric distension and deep abdominal palpation. On the basis of the nature of her spinal cord injury, her brain-gut axis was limited to vagal pathways. Studies in mammalian models of human visceral sensation consistently showed that the subdiaphragmatic vagus contains a homogeneous population of afferents that are activated by low-intensity stimuli, which are generally believed to be important in regulating autonomic function and perhaps contributing to visceral sensory experiences triggered by such low-intensity stimuli (e.g. fullness, nausea), but not pain, although many fibers encode stimuli well into the noxious range. In contrast, spinal afferent pathways include fibers with high-activation thresholds that are thought to represent specialized nociceptors. This illustrative case argues against an exclusive role of specialized nociceptive pathways in visceral pain, but supports a concept of intensity coding with the composite of vagal and spinal input contributing to conscious perception and pain.