Utilizing a complete transection spinal cord injury (SCI) model at the fourth thoracic vertebral level in adult rats, we evaluated whether blocking noxious stimuli below the injury diminishes abnormal somatic and autonomic motor reflexes, manifested in muscular spasticity and hypertensive autonomic dysreflexia, respectively. Gabapentin (GBP) is well-tolerated and currently used to manage neuropathic pain in the SCI population; evidence suggests it acts to decrease presynaptic glutamate release. Since clinical evidence indicates that GBP may suppress muscular spasticity in the chronic SCI population, we hypothesized that preventing neurotransmission of noxious stimuli with GBP eliminates a critical physiological link to these distinct, debilitating SCI-induced secondary impairments.
Behavioural assessments of tail muscle spasticity and mean arterial blood pressure responses to noxious somatic and/or visceral stimulation were used to test the effects of GBP on these abnormal reflexes.
We employed femoral artery catheterization and radio-telemetric approaches to monitor blood pressure alterations in response to noxious colorectal distension (CRD) weeks after complete SCI.