spinal cord electrical stimulation for visceral hypersensitivity in a rodent model of functional...
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Spinal Cord Electrical Stimulation for Visceral Hypersensitivity in a Rodent
Model of Functional Dyspepsia
Geng-Qing Song and Jiande Chen
Veterans Research Foundation, VA Medical Center, Oklahoma City, OK, USA
and
Division of Gastroenterology
University of Texas Medical Branch, Galveston
Functional GI Diseases
Functional dyspepsia
and gastroparesis (25%)Irritable
bowel syndrome
(5-20%)
Gastric esophageal
reflux (14%)
Pain is one of major issuesNo medical therapies…
SCS for Visceral Pain
Visceral pain is common in patients with functional GI diseases; no effective medication therapies
Few animal and human studies have explored potential of SCS for IBS with promising but limited data
FD and gastroparesis are common; visceral pain and gastric hypomotility are major pathological factors in FD
SCS has been reported to improve gastric motility due to its inhibitory effect on sympathetic activity.
Rodent Model of FD with gastric hypersensitivity
FD rats: 10 days old SD received 0.2 ml 0.1% iodoacetamide (IA) in 2% sucrose daily for 6 days and were then allowed to grow adult age (8-11 weeks)
Animal Preparation
SCS electrodes: epidural space at T9/T10
EMG electrodes: at the neck Gastric balloon: for gastric
distention. SCS parameters:
50/100 Hz ; 0.2 ms; 90% of the motor threshold
Exp.1: Effects of SCS on Gastric Hypersensitivity
EMG
Control
Recovery 20 min
SCS
EMG+SCS
Gastric balloon was rapidly inflated to 20, 40, 60, and 80 mmHg for a 20-s stimulation period followed by a 2-min rest and then the procedure was repeated for one more time.
Exp.2: Effects of SCS on Autonomic Function
20 min
Baseline
20 min
GD
20 min
SCS
An electrocardiogram (ECG) was recorded. Autonomic functions were assessed by the spectral
analysis of the heart rate variability which was derived from the ECG.
Blood samples were taken for norepineprine (NE) SCS parameters: 0.2ms/50Hz with 90% MT.
Two recording
electrodes
One reference
electrode20 min
GD+SCS
ECG recording
SCS reduced visceromotor (EMG) response
**
*, P<0.05 vs. baseline
Both 50 and 100 Hz SCS reduced EMG substantially
Effects of FD and SCS on sympathovagal balance
* (P<0.05 vs. baseline); ** (P<0.05 vs. the corresponding GD)
*
**
FD rats showed a significant increase in sympathovagal ratio during GD, this was inhibited by SCS.
SCS suppressed GD-induced NE increase
* (P<0.05 vs. control and baseline); ** (P<0.05 vs. control and the corresponding GD)
*
**
***
FD rats showed a significant increase in NE during GD, this was inhibited by SCS.
Conclusions SCS at T9-T10 with appropriate parameters
ameliorates gastric hyperalgesia induced by GD in a rodent model of FD by inhibiting sympathetic activity.
Combined with its prokinetic effect shown before, SCS may be a potential therapy for functional dyspepsia.
More efforts should be made to explore GI applications of SCS .