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Contribution of P 2 ‐purinoceptors to neurogenic contraction of rat urinary bladder smooth muscle
Author(s) -
Hashimoto Minori,
Kokubun Shinichiro
Publication year - 1995
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.1476-5381.1995.tb14979.x
Subject(s) - suramin , purinergic receptor , medicine , endocrinology , stimulation , contraction (grammar) , adenosine , muscle contraction , adenosine triphosphate , atropine , chemistry , adenosine diphosphate , uridine triphosphate , detrusor muscle , urinary bladder , biology , receptor , biochemistry , nucleotide , platelet , platelet aggregation , gene
1 The contribution of P 2 ‐purinoceptors to neurogenic contraction was investigated in rat urinary bladder smooth muscle by measurement of isotonic tension. 2 Contraction of rat urinary bladder smooth muscle induced by electrical stimulation was decreased to 84.19±3.90% of the control ( n = 16) in the presence of atropine (1 μ m ), which was further decreased to 38.80 ±2.75% of the control ( n = 49) in the presence of both atropine and 10 μ m α,β‐methylene adenosine 5′‐triphosphate (α,β‐Me ATP). 3 The contractile response induced by electrical stimulation in the presence of atropine and α,β‐Me ATP was decreased to 27.81 ±4.07% ( n = 23) and 26.63 ±5.01% ( n = 15) of the control, by the addition of 100 μ m cibacron blue 3GA and 100 μ m suramin, respectively. The application of 100 μ m adenosine 5′‐0–2‐thiodiphosphate (ADPβS) in the presence of atropine and α,β‐Me ATP decreased the contractile response induced by electrical stimulations to 17.15 ±3.71% ( n =15) of the control. 4 Pretreatment of muscle strips with 100 μ m ADPβS significantly reduced the response to either 200 μ m α,β‐methylene adenosine 5′‐diphosphate or 200 μ m ADPβS. 5 Uridine 5′‐triphosphate (100 μ m to 1 mM) concentration‐dependently contracted muscle strips, and this contraction was significantly antagonized by desensitization of P 2 ‐receptors with α,β‐Me ATP (10 μ m ), and completely antagonized by pretreatment of muscle strips with both α,β‐Me ATP and ADPβS (100 μ m ). 6 Di(adenosine‐5′) tetraphosphate (30 and 100 μ m ) contracted muscle strips, whereas it failed to contract after desensitization of P 2 ‐receptors. 7 It is suggested that about 20% of the neurogenic contraction of rat urinary bladder smooth muscle is mediated via ADPβS‐sensitive purinoceptors.