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Subtypes of purinoceptors in rat and dog urinary bladder smooth muscles
Author(s) -
Suzuki Hideka,
Kokubun Shinichiro
Publication year - 1994
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1994.tb13039.x
Subject(s) - purinergic receptor , contraction (grammar) , endocrinology , muscle contraction , medicine , adenosine , urinary bladder , desensitization (medicine) , detrusor muscle , chemistry , adenosine triphosphate , suramin , biology , receptor
1 Both adenosine and adenosine 5′‐triphosphate (ATP) (10 μ m and 100 μ m ) relaxed 10 μ m acetylcholine (ACh)‐induced contraction of rat bladder strips, which was completely antagonized by 100 μ m 8‐( p ‐sulphophenyl) theophylline. In dog bladder neither adenosine nor ATP inhibited ACh‐induced contraction. 2 P 2x ‐purinoceptor agonists contracted both rat and dog bladder strips with the potency order of α,β‐MeATP > ATP > ADP. 3 α,β‐MeADP (100 μ m ) induced a contraction of the rat bladder strip even after desensitization of P 2x ‐purinoceptors but failed to contract the dog bladder strip. 4 2‐MeSATP (1 μ m to 300 μ m ) concentration‐dependently induced contraction of rat bladder strips; this contraction was significantly inhibited after desensitization of P 2x ‐purinoceptors. Cibacron blue 3GA (100 μ m ) antagonized the drug at concentrations lower than 30 μ m , whereas it augmented the response to the drug at concentrations above 30 μ m . 5 ADPβS (1 μ m to 1 m m ) concentration‐dependently induced contraction of rat bladder strips after desensitization of P 2x ‐purinoceptors; a contraction which was significantly antagonized by cibacron blue 3GA (100 μ m ). 6 It is concluded that three subtypes of purinoceptors, P 1 (mediating relaxation), and P 2x and another type of P 2 (mediating contraction), exist in rat urinary bladder smooth muscle, whereas a single subtype of the receptor, P 2x ‐purinoceptor (mediating contraction) occurs in dog urinary bladder smooth muscle.