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目的:研究尿苷三磷酸(UTP)对豚鼠乳头状肌的电生理作用,及UIP作用的相关受体。方法:利用细胞内微电极技术记录豚鼠乳头状肌跨膜电位。结果:UTP、ATP和ADP均可浓度依赖性延长豚鼠乳头状肌动作电位时程(APD)。激动剂的效应强度序列为UTP=ATP>ADP,且UTP和ATP的作用存在交叉脱敏现象。Adenosine(Ado)和α,β-methyleneATP(α,β-MeATP)对豚鼠乳头状肌动作电位各参数均无影响,氨茶碱持续灌流亦不影响UTP的作用。与UTP 3mmol/L等渗的ceftriaxonum(3mmol/L)或NaCl(9mmol/L)可显著但轻微地延长APD。结论:UTP延长豚鼠乳头状肌APD的作用由特异性和非特异性两种作用组成,前者与P2Y_2受体有关。
AIM: To investigate the electrophysiological effects of uridine triphosphate (UTP) on papillary muscles of guinea pigs and related receptors of UIP. Methods: The transmembrane potential of guinea pig papillary muscles was recorded by intracellular microelectrode technique. Results: Both UTP, ATP and ADP prolonged the APD of guinea pig papillary muscles in a concentration - dependent manner. The sequence of agonist potency is UTP = ATP> ADP, and there is cross-desensitization of the interaction between UTP and ATP. Adenosine (Ado) and α, β-methyleneATP (α, β-MeATP) had no effect on the parameters of guinea pig papillary muscles. Sustained perfusion of aminophylline did not affect the effect of UTP. APD was significantly but slightly prolonged with ceftriaxonum (3 mmol / L) or NaCl (9 mmol / L) isotonic with UTP 3 mmol / L. CONCLUSION: The effect of UTP prolongation of APD in guinea pig papillary muscle consists of both specific and nonspecific effects, the former is related to P2Y_2 receptor.