Role of capsaicin sensitive nerves in epidermal growth factor effects on gastric mucosal injury and blood flow.
BACKGROUND
Epidermal growth factor (EGF) and capsaicin protect against experimental gastric mucosal injury. Capsaicin exerts its gastroprotective effect by stimulating afferent neurones leading to release of calcitonin gene related peptide (CGRP) which causes gastric hyperaemia. EGF also causes gastric hyperaemia but whether it acts via capsaicin sensitive neurones is unknown.


OBJECTIVE
To assess the influence of: (1) capsaicin desensitisation on EGF effects on gastric mucosal injury and gastric mucosal blood flow: and (2) close arterial infusion of hCGRP8-379, a CGRP antagonist, on EGF effects on gastric mucosal blood flow.


METHODS
The absolute ethanol induced gastric mucosal injury model in the rat was used. Gastric mucosal damage was assessed by planimetry and light microscopy. Gastric mucosal blood flow was measured by laser Doppler flowmetry in a gastric chamber preparation.


RESULTS
Capsaicin desensitisation abolished the gastroprotective and gastric hyperaemic effects of EGF. Close arterial infusion of hCGRP8-37 antagonised the hyperaemic effect of both capsaicin and EGF.


CONCLUSIONS
Results show that EGF may exert its gastroprotective and gastric hyperaemic effects via capsaicin sensitive afferent neurones.
Kang
J Y
JY
Department of Medicine, National University of Singapore.
Teng
C H
CH
Chen
F C
FC
Wee
A
A
D000818:Animals; D015740:Calcitonin Gene-Related Peptide / Q000037:antagonists & inhibitors / Q000494:pharmacology; D002211:Capsaicin / Q000494:pharmacology*; D004815:Epidermal Growth Factor / Q000494:pharmacology*; D000431:Ethanol / Q000009:adverse effects; D005753:Gastric Mucosa / Q000098:blood supply / Q000187:drug effects* / Q000294:innervation; D017078:Laser-Doppler Flowmetry; D008297:Male; D008916:Miotics / Q000494:pharmacology; D009475:Neurons, Afferent / Q000187:drug effects*; D010446:Peptide Fragments / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012039:Regional Blood Flow / Q000187:drug effects
D008916:Miotics; D010446:Peptide Fragments; C058636:calcitonin gene-related peptide (8-37); D000431:Ethanol; D004815:Epidermal Growth Factor; D015740:Calcitonin Gene-Related Peptide; D002211:Capsaicin