Distribution of beta-adrenoceptor subtypes in gastrointestinal tract of nondiabetic and diabetic BB rats. A longitudinal study.
The effects of aging and diabetes on the distribution of beta-adrenoceptor subtypes in the gut were investigated in the BB rat. [125I]Cyanopindolol binding to 10-micron sections was evaluated using film autoradiography. Cyanopindolol binding to beta-, beta 1-, and beta 2-adrenoceptors was displaced by 1 microM propranolol, 50 nM ICI-89-406, and 100 nM ICI-118-551, respectively. beta-Adrenoceptor binding was highest in the circular muscle of proximal colon and lowest in the pylorus of 4- to 5-month-old rats. Aging (8- to 10-month-old vs. 4- to 5-month-old rats) was associated with increased beta-adrenoceptor binding in the pylorus and reduced binding in the proximal colon. Diabetes had a time-dependent effect on the level of beta-adrenoceptor binding. It was increased in the antral and pyloric stomach but longer periods of diabetes caused a reduction in beta-adrenoceptor binding in the pylorus. Those in the intestine were reduced time-dependently and involved beta 1- or beta 2-adrenoceptors or both.
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Division of Gastroenterology, Hospital of the University of Pennsylvania, Philadelphia 19104, USA.
Ouyang
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D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000375:Aging / Q000378:metabolism*; D000818:Animals; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism*; D003922:Diabetes Mellitus, Type 1 / Q000378:metabolism*; D004064:Digestive System / Q000378:metabolism*; D008297:Male; D010869:Pindolol / Q000031:analogs & derivatives / Q000494:pharmacology; D051381:Rats; D011913:Rats, Inbred BB; D011943:Receptors, Adrenergic, beta / Q000187:drug effects / Q000378:metabolism*; D013997:Time Factors
D000319:Adrenergic beta-Antagonists; D011943:Receptors, Adrenergic, beta; C047975:cyanopindolol; D010869:Pindolol