Functional interaction between transforming growth factor alpha and capsaicin-sensitive sensory neurons in the rat stomach.
OBJECTIVE
Transforming growth alpha (TGFalpha) and sensory neurons have been shown to promote gastric mucosal protection and healing. Aims were to examine in vitro interactions between gastric sensory neurons, the sensory neuropeptide calcitonin gene-related peptide (CGRP), and TGFalpha.


METHODS
Gastric mucosal/submucosal tissue fragments from Sprague-Dawley (SD) rats were incubated in short-term (30 min) culture. Peptide release into media and TGFalpha tissue content were measured by radioimmunoassay.


RESULTS
TGFalpha (1 x 10(-8) to 1 x 10(-6) M) caused dose-dependent stimulation of CGRP release. Maximal CGRP release (+87%) was observed with 1 x 10(-6) M TGFalpha: 28.6+/-3.8 vs. control of 15.5+/-2.7 pg/g tissue; P<0.05. Both CGRP (1 x 10(-7) to 1 x 10(-5) M) and capsaicin (1 x 10-(8) to 1 x 10(-6)M) significantly inhibited basal TGFalpha release in a dose-dependent fashion that ranged from -20% to -39%. In contrast, capsaicin-induced sensory denervation caused significant increases in both basal TGFalpha release and TGFalpha tissue content.


CONCLUSIONS
Function interactions between TGFalpha and gastric sensory neurons are suggested by the observations that (1) TGFalpha stimulated CGRP release from gastric sensory neurons; (2) CGRP and acute capsaicin treatment inhibited TGFalpha release and; (3) capsaicin-induced sensory denervation caused significant increases in both gastric TGFalpha basal release and tissue content.
Vongthavaravat
Verapan
V
Division of Gastroenterology, Department of Medicine, University of Oklahoma Health Sciences Center and Oklahoma City Department of Veterans Affaris Medical Center, USA.
Saymeh
Layth A
LA
Mesiya
Sikandar A
SA
Dunn
S Terence
ST
Harty
Richard F
RF
D000818:Animals; D015740:Calcitonin Gene-Related Peptide / Q000378:metabolism* / Q000494:pharmacology; D002211:Capsaicin / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D005753:Gastric Mucosa / Q000294:innervation / Q000378:metabolism*; D066298:In Vitro Techniques; D008297:Male; D009475:Neurons, Afferent / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D016211:Transforming Growth Factor alpha / Q000378:metabolism* / Q000494:pharmacology
D016211:Transforming Growth Factor alpha; D015740:Calcitonin Gene-Related Peptide; D002211:Capsaicin