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Characterization Of The Α1-Adrenoceptor Subtype Mediating Contractions Of The Pig Internal Anal Sphincter, K. Mills, Natasha Hausman, Russ Chess-Williams
Characterization Of The Α1-Adrenoceptor Subtype Mediating Contractions Of The Pig Internal Anal Sphincter, K. Mills, Natasha Hausman, Russ Chess-Williams
Russ Chess-Williams
Background and purpose: The internal anal sphincter has been shown to contract in response to a1-adrenoceptor stimulation and therefore a1-adrenoceptor agonists may be useful in treating faecal incontinence. This study characterizes the a1-adrenoceptor subtype responsible for mediating contraction of the internal anal sphincter of the pig.
Experimental approach: The potency of agonists and the affinities of several receptor subtype selective antagonists were determined on smooth muscle strips for the pig internal anal sphincter. Cumulative concentration–response curves were performed using phenylephrine and noradrenaline.
Key results: The potency of the a1A-adrenoceptor selective agonist A61603 (pEC50¼7.79±0.04) was 158-fold greater than that for noradrenaline …