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Query: UMLS:C0033377 (prolapse)
 11,717 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Recently, a rodent model of nicotine abstinence syndrome has been developed based on observing the frequency of spontaneous behavioral signs following termination of continuous subcutaneous infusion of nicotine tartrate. In the present study, the nicotinic antagonist mecamylamine precipitated an abstinence syndrome in nicotine-dependent rats. Twelve rats were each infused for 7 days with 9 mg/kg per day nicotine tartrate in saline via Alzet osmotic minipumps; another 12 rats were sham-operated and remained nicotine-naive. Six rats from each group received 1 mg/kg mecamylamine in saline SC immediately before a 30-min observation, while the remaining six rats from each group received saline alone. Nicotine-infused rats receiving mecamylamine exhibited significantly more (P < 0.01), overall abstinence signs than all other groups. In terms of categories of signs, they displayed significantly more gasps/writhes, teeth chatter/chews, shakes/tremors and ptosis. In a second experiment utilizing only nicotine-naive rats, a far higher dose of mecamylamine (5 mg/kg sc) induced a quasi-nicotine abstinence syndrome. The results provide further validation for this rodent model of nicotine abstinence syndrome.
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PMID:The nicotinic antagonist mecamylamine precipitates nicotine abstinence syndrome in the rat. 786 93

Abrupt tobacco/nicotine cessation after chronic use causes various withdrawal symptoms/signs. There is evidence that dysfunction of brain dopaminergic system might be responsible for some nicotine withdrawal symptoms. The hypothesis for the present study was that different dopaminergic agonists would relieve different nicotine withdrawal signs. Adult male Sprague-Dawley rats were used. (-)-Nicotine bitartrate (9 mg/kg/day, salt content) or equimolar sodium tartrate was infused into each rat via a subcutaneous (s.c.) osmotic minipump for 7 days. To assess nicotine withdrawal signs, several somatic abstinence signs including teeth-chattering/chews, stretches/gasps, ptosis, shakes, and yawns were counted one day after removal of pumps. These signs were attenuated by the s.c. injection of 0.4 mg/kg nicotine bitartrate. Both a dopamine D(1/5) agonist (SKF81297) and a D(2/3) agonist (pramipexole) relieved abstinence signs dose-dependently but differentially. SKF81297 (0.32 mg/kg, s.c.) reduced teeth-chattering/chews but not shakes. Pramipexole (1mg/kg, s.c.) decreased both teeth-chattering/chews and shakes. A low dose of pramipexole (0.1mg/kg, s.c.) significantly increased yawns, consistent with previous studies that the stimulation of D(3) receptors induces yawning. These results indicate that a D(2)-selective agonist should be considered a candidate to relieve nicotine withdrawal symptoms.
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PMID:Dopamine D1/5 and D2/3 agonists differentially attenuate somatic signs of nicotine withdrawal in rats. 2162 84