Predictable and unpredictable shock stimulates gastric contractility and causes mucosal injury in rats.
The effects of tailshock on gastric contractility and lesions were investigated in rats exposed to 100 1-mA tailshocks while confined inside plastic tubes. A light preceded each shock in one group and was randomly presented with respect to shock in the other. Following the session, animals were given 3 hr of rest before being sacrificed. Contractility of the corpus of the stomach was measured by means of chronically implanted extraluminal force transducers. Contractility was measured in 10-min blocks and analyzed by computer. Lesions were quantified by inspection; quantitative histology was performed on corpus and antrum sections. Signaled (n = 13) and unsignaled (n = 17) shock stimulated high-amplitude gastric contractions in fasted rats, which continued for 2 hr after the shock session. Cumulative contractile activity (1.5-hr shock plus 2-hr rest) in shocked animals was twice that in restrained and unrestrained control animals (n = 19, p less than .05), and contractile activity had a 30%-40% greater average amplitude than after a meal. Compared with unrestrained controls, shocked rats had visibly more mucosal injury (2.2 +/- 0.5 mm2 vs. 0.1 +/- 0 mm2). Larger cumulative contractile activity was associated with a larger area of erosions (r = .36, p less than .05). Frequency and duration of contractions did not distinguish between shocked and unshocked groups. We conclude that in rats, signaled and unsignaled tailshock stimulates persistent, high-amplitude gastric contractions and is associated with injury of the mucosa of the stomach.
Garrick
T
T
Department of Psychiatry, West Los Angeles Veterans Administration Medical Center, California 90073.
Minor
T R
TR
Bauck
S
S
Weiner
H
H
Guth
P
P
D000818:Animals; D004597:Electroshock; D005753:Gastric Mucosa / Q000473:pathology* / Q000503:physiopathology; D009119:Muscle Contraction; D009130:Muscle, Smooth / Q000503:physiopathology*; D051381:Rats; D011919:Rats, Inbred Strains; D013272:Stomach Diseases / Q000209:etiology / Q000473:pathology / Q000503:physiopathology*; D013315:Stress, Psychological / Q000150:complications / Q000503:physiopathology*