Huizinga J D, Den Hertog A
Eur J Pharmacol. 1980 May 16;63(4):259-65. doi: 10.1016/0014-2999(80)90253-8.
The effect of theophylline on the ATP response, the adenosine response and the inhibitory junction potential was studied on circular smooth muscle preparations of the guinea-pig stomach. The amplitude of the inhibitory junction potential evoked after stimulation of the non-cholinergic, non-adrenergic nervous system was not affected by a moderate concentration of theophylline (5 x 10(-6)-10(-5) M). At higher concentrations (5 x 10(-5)-10(-3) M) theophylline relaxed the muscle hyperpolarized the cell membrane and reduced the inhibitory junction potential slightly. ATP and adenosine (5 x 10(-6)-10(-3) M) also caused relaxation of the smooth muscle cells and hyperpolarization of the cell membrane. Theophylline (5 x 10(-6)-10(-3) M) did not antagonize these effects; in the presence of theophylline (5 x 10(-5)-10(-3) M) additional relaxations produced by ATP and adenosine were limited in view of the muscle tone. These results indicate that theophylline does not inhibit either the effect of the non-adrenergic inhibitory transmitter on the smooth muscle cells of the guinea-pig stomach or the actions of ATP and adenosine. This suggests that the existence of theophylline-sensitive adenosine receptors in the stomach-muscle cell membrane is unlikely and that theophylline is not the drug of choice to support the purinergic nerve hypothesis.
在豚鼠胃环形平滑肌标本上研究了茶碱对ATP反应、腺苷反应和抑制性接头电位的影响。刺激非胆碱能、非肾上腺素能神经系统后诱发的抑制性接头电位的幅度不受中等浓度茶碱（5×10⁻⁶ - 10⁻⁵M）的影响。在较高浓度（5×10⁻⁵ - 10⁻³M）时，茶碱使肌肉松弛，使细胞膜超极化，并略微降低抑制性接头电位。ATP和腺苷（5×10⁻⁶ - 10⁻³M）也引起平滑肌细胞松弛和细胞膜超极化。茶碱（5×10⁻⁶ - 10⁻³M）并未拮抗这些作用；在存在茶碱（5×10⁻⁵ - 10⁻³M）的情况下，鉴于肌张力，ATP和腺苷产生的额外松弛作用受到限制。这些结果表明，茶碱既不抑制非肾上腺素能抑制性递质对豚鼠胃平滑肌细胞的作用，也不抑制ATP和腺苷的作用。这表明胃肌细胞膜中不太可能存在对茶碱敏感的腺苷受体，并且茶碱不是支持嘌呤能神经假说的首选药物。
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