Ovarian hormone modulates 5-hydroxytryptamine 3 receptors mRNA expression in rat colon with restraint stress-induced bowel dysfunction.
OBJECTIVE
To examine the effects of ovarian hormone on the expression of 5-hydroxytryptamine 3 receptors (5-HT3R) in rat colon of restraint stress-induced bowel dysfunction.


METHODS
Twenty-four female Sprague-Dawley rats were randomly divided into three groups of 8 each: sham operation, ovariectomy (OVX) and ovariectomy with estrogen (E2) and progesterone (P) replacement therapy (OVX+E2+P). The rats were subjected to 1-h restraint stress 4 wk after operation. The changes of defecation were monitored by collection of fecal pellets. The gonadal steroids were measured in duplicate by radioimmunoassay (RIA). The expression of 5-HT3R mRNA in the colon was studied by RT-PCR.


RESULTS
Compared with sham group and OVX+E2+P group, OVX group showed increase in fecal pellets and decrease in the time of vitreous pellets excretion (P<0.01). Serum levels of E2 and P were suppressed in OVX group and restored following treatment with ovarian steroids (P<0.01), and the levels of 5-HT3R mRNA in the colon of ovariectomized rats were significantly increased, the expression of 5-HT3R mRNA was significantly decreased in hormone replacement therapy group (P<0.01).


CONCLUSIONS
Ovarian hormone plays a role in the regulation of 5-HT3R expressions in restraint stress-induced bowel dysfunction of rats. The interactions between ovarian steroids and gastrointestinal tract may have major pathophysiological implications in 5-HT-related disorders, such as irritable bowel syndrome (IBS).
Li
Tian-Jin
TJ
Department of Gastroenterology, Renmin Hospital, Wuhan University, Wuhan 430060, Hubei Province, China.
Yu
Bao-Ping
BP
Dong
Wei-Guo
WG
Luo
He-Sheng
HS
Xu
Long
L
Li
Mu-Qi
MQ
D000818:Animals; D003106:Colon / Q000503:physiopathology; D003672:Defecation; D004958:Estradiol / Q000494:pharmacology*; D005260:Female; D015870:Gene Expression / Q000187:drug effects; D043183:Irritable Bowel Syndrome / Q000209:etiology / Q000503:physiopathology*; D010052:Ovariectomy; D011374:Progesterone / Q000494:pharmacology*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D044406:Receptors, Serotonin, 5-HT3 / Q000235:genetics*; D012149:Restraint, Physical; D013312:Stress, Physiological / Q000150:complications / Q000503:physiopathology*
D012333:RNA, Messenger; D044406:Receptors, Serotonin, 5-HT3; D011374:Progesterone; D004958:Estradiol