Central neural mechanisms mediating human visceral hypersensitivity.
Although visceral hypersensitivity is thought to be important in generating symptoms in functional gastrointestinal disorders, the neural mechanisms involved are poorly understood. We recently showed that central sensitization (hyperexcitability of spinal cord sensory neurones) may play an important role. In this study, we demonstrate that after a 30-min infusion of 0.15 M HCl acid into the healthy human distal esophagus, we see a reduction in the pain threshold to electrical stimulation of the non-acid-exposed proximal esophagus (9.6 +/- 2.4 mA) and a concurrent reduction in the latency of the N1 and P2 components of the esophageal evoked potentials (EEP) from this region (10.4 +/- 2.3 and 15.8 +/- 5.3 ms, respectively). This reduced EEP latency indicates a central increase in afferent pathway velocity and therefore suggests that hyperexcitability within the central visceral pain pathway contributes to the hypersensitivity within the proximal, non-acid-exposed esophagus (secondary hyperalgesia/allodynia). These findings provide the first electrophysiological evidence that central sensitization contributes to human visceral hypersensitivity.
Sarkar
S
S
Section of Gastrointestinal Sciences, University of Manchester, Hope Hospital, Salford M6 8HD, United Kingdom.
Hobson
A R
AR
Furlong
P L
PL
Woolf
C J
CJ
Thompson
D G
DG
Aziz
Q
Q
D000328:Adult; D002490:Central Nervous System / Q000503:physiopathology*; D004558:Electric Stimulation; D004947:Esophagus / Q000187:drug effects / Q000503:physiopathology*; D005071:Evoked Potentials / Q000187:drug effects; D005260:Female; D006801:Humans; D006851:Hydrochloric Acid / Q000494:pharmacology; D006941:Hyperesthesia / Q000139:chemically induced / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D017288:Pain Threshold / Q000187:drug effects; D011930:Reaction Time / Q000187:drug effects; D012677:Sensation / Q000187:drug effects; D012965:Sodium Chloride / Q000494:pharmacology
D012965:Sodium Chloride; D006851:Hydrochloric Acid