Intracerebroventricular calcitonin prevents stress-induced gastric dysfunction.
BACKGROUND
Restraint stress produces gastric hypercontractility and acidity leading to stress ulceration. Intracerebroventricular (ICV) salmon calcitonin (sCT) decreases restraint injury and acidity, but its effects on restraint-induced hypercontractility are unknown.


METHODS
Using stereotactic guidance, ICV catheters were placed into the lateral ventricle of adult male rats and calibrated gastric strain gauge transducers were implanted 5 days prior to restraint stress. sCT rats (n = 8) were pretreated with 5 microg of calcitonin ICV (10 microl volume), while controls (n = 10) received 10 microl of ICV saline prior to restraint for 2 h at 20 degrees C followed by 2 h at 4 degrees C. Gastric motility data were collected with AT-CODAS and analyzed with ADVANCED CODAS. Gastric volume, pH, and lesions were recorded following the stress.


RESULTS
ICV calcitonin prevented gastric mucosal injury in all animals (0% vs 100%, P <.01) and elevated pH slightly (2.5 +/-.3 vs 1.6 +/-.1, P <.05). Stress caused the force of contractions to increase from 0.35 +/-.1 to 1.38 +/-.4 g in controls (P <.01), while treated animal's force fell from.42 +/-.1 to 0.2 +/-.05 g (P <.01 vs control). Stress did not affect contractions/min (3.4 +.6 vs 3.5 +.3), but sCT increased frequency (2.5 +.4 to 5.0 +.2, P <.01). Stress prolonged contraction duration (11.5 + 1 to 16.5 + 1.7 s, P <.01), but stress's effect was prevented by sCT (11.0 +.5 to 11.2 +.3, P <.01 vs control).


CONCLUSIONS
Pretreatment with 5 microg central sCT prevents the increased amplitude and duration of gastric contractions produced by restraint stress for 2 h, in association with gastroprotection.
DuBay
Derek
D
Department of Surgery, VAMC Iowa City and University of Iowa College of Medicine, Iowa City, Iowa 52246, USA.
Ephgrave
Kimberly S
KS
Cullen
Joseph J
JJ
Broadhurst
Kimberly A
KA
D000818:Animals; D002116:Calcitonin / Q000008:administration & dosage*; D019610:Cytoprotection; D005769:Gastrointestinal Motility / Q000187:drug effects; D007276:Injections, Intraventricular; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D012149:Restraint, Physical; D013272:Stomach Diseases / Q000209:etiology* / Q000503:physiopathology / Q000517:prevention & control*; D013312:Stress, Physiological / Q000150:complications* / Q000209:etiology; D013997:Time Factors
D002116:Calcitonin