Spinal cord injury alters purinergic neurotransmission to mesenteric arteries in rats.

Spinal cord injury alters purinergic neurotransmission to mesenteric arteries in rats. Am J Physiol Heart Circ Physiol. 2019 Nov 27;: Authors: Sangsiri S, Xu H, Fernandes R, Fink GD, Lujan HL, DiCarlo SE, Galligan JJ Abstract Complications associated with spinal cord injury (SCI) result from unregulated reflexes below the lesion level. Understanding neurotransmission distal to the SCI could improve quality of life by mitigating complications. The long-term impact of SCI on neurovascular transmission is poorly understood but reduced sympathetic activity below the site of SCI enhances arterial neurotransmission (1). We studied sympathetic neurovascular transmission using a rat model of long-term paraplegia (T2-3) and tetraplegia (C6-7). Sixteen weeks after SCI, T2-3 and C6-7 rats had lower blood pressure (BP) than sham rats (103±2 and 97±4 vs 117±6 mmHg, P<0.05). T2-3 rats had tachycardia (410±6 bpm), and C6-7 rats had bradycardia (299±10 bpm) compared to intact rats (321±4 bpm, P<0.05). Purinergic excitatory junction potentials (EJPs) were measured in mesenteric arteries (MAs) using microlectrodes and norepinephrine (NE) release was measured using amperometry. NE release was similar in all groups while EJP frequency-response curves from T2-3 and C6-7 rats were left-shifted vs. sham rats. EJPs in T2-3 and C6-7 rats showed facilitation followed by run-down during stimulation trains (10 Hz, 50 stimuli). MA reactivity to exoge...
Source: American Journal of Physiology. Heart and Circulatory Physiology - Category: Physiology Authors: Tags: Am J Physiol Heart Circ Physiol Source Type: research