tetragastrin and Body-Weight

This study addressed the proposed memory-modulating effect of the cholecystokinin (CCK) 2 agonist Boc-CCK-4 in rats using a Morris water maze. In the brain, CCK is colocalized and interacts with dopamine, respectively. To impair dopaminergic neurotransmission, and consequently, dopamine-mediated learning and memory, rat pups received the neurotoxin 6-hydroxydopamine (6-OHDA) into the left [Day 5 postnatal (p.n.)] and right (Day 8 p.n.) ventricles (50 microg/5 microl each). After 6-OHDA treatment, dopamine brain levels were reduced by 60% on Day 50 p.n. Lesioned rats had a lower body weight but normal swimming abilities. In the acquisition phase of the water maze (Day 50 p.n.), sham-lesioned rats learned quickly, compared to lesioned rats. Treatment with Boc-CCK-4 (40 microg/kg ip) did not affect performance in sham-lesioned rats but restored the learning curve in lesioned rats without increasing swimming speed indicating a better spatial learning in the dopamine-depleted rats. In summary, these findings demonstrate that stimulation of CCK2 receptors may counteract cognitive deficits of dopamine-depleted rats.

Topics: Animals; Animals, Newborn; Body Weight; Brain Chemistry; Dopamine; Female; Hyperkinesis; Maze Learning; Memory; Motor Activity; Oxidopamine; Pregnancy; Psychomotor Performance; Rats; Rats, Wistar; Receptors, Cholecystokinin; Swimming; Sympathectomy, Chemical; Tetragastrin

We studied the behavioral effects of a novel cholecystokinin tetrapeptide (CCK-4) analogue, A71623, with full agonist activity and high affinity and selectivity for the CCK-A receptor subtype relative to the CCK-B receptor. In tests for anorectic activity, A71623 was found to suppress 60-min intakes of a liquid diet in both deprived and sated rats, and the effects were blocked by a selective CCK-A antagonist, A70104. Compared with CCK-8, A71623 was found to have improved potency and duration of action; the most potent route of administration was intraperitoneal. A71623 also suppressed the intake of a liquid diet and a 0.2 M sucrose solution in lean and obese Zucker rats. In daily injection studies, the anorectic activity of CCK-8 diminished rapidly, whereas the suppressant effects of A71623 on food intakes and body weight gains persisted throughout the 11-day treatment period. Finally, A71623 reduced the spontaneous locomotor activity of rats at doses above those required to suppress intakes. These studies are the first to describe the behavioral effects of a potent and highly selective CCK-A receptor agonist.

Topics: Animals; Anorexia; Behavior, Animal; Body Weight; Cholecystokinin; Circadian Rhythm; Eating; Food Deprivation; Male; Motor Activity; Peptides; Rats; Rats, Inbred Strains; Sincalide; Tetragastrin; Time Factors

The effect of tetragastrin on pancreatic tumors induced by azaserine was investigated in Wistar rats. Rats were given 25 weekly injections of 10 mg/kg body weight of azaserine and 1 mg/kg body weight of tetragastrin as a suspension in olive oil every other day. Carcinogen-induced pancreatic lesions were examined by histochemical techniques, and were classified as ATPase-positive or ATPase-negative. In week 62, quantitative histological analysis showed that prolonged administration of tetragastrin had little or no influence on the number and size of the carcinogen-induced pancreatic lesions, although it caused significantly increased cell proliferation, indicated by a greater labelling index of the pancreatic acinar cells.

Topics: Adenosine Triphosphatases; Animals; Azaserine; Body Weight; Cell Division; Gastrins; Male; Mitotic Index; Organ Size; Pancreatic Neoplasms; Rats; Rats, Inbred Strains; Tetragastrin

Subcutaneous injections of a large dose of tetragastrin (2 mg/day) into a rat for 4 weeks caused hypertrophy of parietal cells of the stomach, intestinal glandular cells of the duodenum, and pancreatic acinar cells. Ths histometrical analysis revealed that these trophic effects of tetragastrin were produced in varying degrees in different sites.

Topics: Animals; Body Weight; Duodenum; Gastrins; Male; Pancreas; Rats; Stomach; Tetragastrin