- Existance of cholinergic and purinergic receptor on the detrusor muscle of rat urinary bladder.
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Tae Su Choi, Oh Cheol Kwon, Jeoung Hee Ha, Kwang Youn Lee, Won Joon Kim
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Yeungnam Univ J Med. 1991;8(2):138-149. Published online December 31, 1991
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DOI: https://doi.org/10.12701/yujm.1991.8.2.138
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Abstract
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- This study was aimed at investigation of the stimulatory innervations on the rat urinary bladder. Detrusor muscle strips of 15 mm long were suspended in isolated muscle chambers containing 1 ml of PSS maintained at 37℃ and aerated with 95% O²/5% Co². Isometric myography was performed, and the results were as followings: Muscle strips showed “on-contraction” by electric field stimulation (EFS) frequency-dependently. The EFS-induced contraction was not affected by hexamethonium, a ganglion blocker, but abolished by tetrodotoxin, a nerve conduction blocker. Physostigmine, a cholinesterase inhibitor enhanced the EFS-induced contraction which was inhibited by hemicholinium, an inhibitor of choline uptake at the cholinergic nerve ending. Such an EFS-induced contraction was antagonized by atropine only partially, and the atropine-resistant portion was completely abolished by the desensitization of purinergic receptors by prolonged incubating of the strips in the presence of high concentration of ATP. Bethanechol, a cholinergic agonist, elicited concentration-dependent contraction. Adenosine triphosphate (ATP), a purinergic agonist, induced a weak but concentration-dependent contraction of short duration. Bethanechol-induced contraction was not affected by ATP-desensitization, and ATP-induced contraction was not affected by tetrodotoxin. These results suggest that there are at least two main stimulatory components of innervations in the detrusor muscle, cholinergic muscarinic and purinergic; and those receptors are independent each other.
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