Assessment of the visceral afferent and autonomic pathways in response to esophageal stimulation in control subjects and in patients with diabetes.
OBJECTIVE
To examine the effects of esophageal stimulation on vagal afferent and efferent pathways in volunteers without diabetes and patients with diabetes.


METHODS
Prospective physiological study.


METHODS
Fourteen control subjects without diabetes and 6 patients with diabetes.


METHODS
Electrical and mechanical stimulation of the esophagus.


METHODS
Cortical evoked potentials and the power spectra of heart rate variability.


RESULTS
For the control subjects, there was a significant decrease in the ratio of the low frequency to high frequency (LF:HF) power (i.e., increased vagal efferent modulation) during stimulation. Reproducible cortical evoked potentials were obtained from all control subjects. In the 6 patients with diabetes, who had viscerosensory and autonomic neuropathy, the cortical evoked potentials showed an erratic non-reproducible response to electrical esophageal stimulation; however, the LF:HF ratio decreased in these patients during stimulation, suggesting an intact subcortical reflex circuit.


CONCLUSIONS
Vago-afferent fibres can be studied using minimally invasive techniques, and the power spectral analysis of heart rate variability permits study of autonomic vago-efferent pathways.
Kamath
M V
MV
Department of Medicine, McMaster University, Hamilton.
Tougas
G
G
Fitzpatrick
D
D
Fallen
E L
EL
Watteel
R
R
Shine
G
G
Upton
A R
AR
D000293:Adolescent; D000328:Adult; D001341:Autonomic Nervous System / Q000502:physiology* / Q000503:physiopathology; D002404:Catheterization; D002540:Cerebral Cortex / Q000502:physiology / Q000503:physiopathology; D002648:Child; D003922:Diabetes Mellitus, Type 1 / Q000503:physiopathology*; D003929:Diabetic Neuropathies / Q000503:physiopathology*; D004558:Electric Stimulation; D004947:Esophagus / Q000294:innervation*; D005071:Evoked Potentials; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D009475:Neurons, Afferent / Q000502:physiology*; D014630:Vagus Nerve / Q000502:physiology / Q000503:physiopathology