Fedan J S, Grant L J
Physiology Section, National Institute for Occupational Safety and Health, Morgantown, WV 26505, USA.
Eur J Pharmacol. 1995 Aug 4;281(2):213-7. doi: 10.1016/0014-2999(95)00352-l.
Previous studies have shown that treatment of guinea-pig isolated vas deferens with the affinity label periodate-oxidized ATP (2',3'-dialdehyde ATP), results in two irreversible effects on biphasic contractile responses to ATP, i.e., potentiation of the P2X purinoceptor-mediated first phase and inhibition of the ecto-kinase-mediated second phase. The present experiments were designed to evaluate whether periodate-oxidized ADP, periodate-oxidized AMP, and periodate-oxidized adenosine, produce similar effects. Periodate-oxidized ATP and periodate-oxidized ADP (10(-2) M) elicited contraction of the vas deferens (periodate-oxidized ATP > periodate-oxidized ADP; periodate-oxidized AMP and periodate-oxidized adenosine had no agonist activity. After incubation of the preparations for 5 min with 10(-2) M periodate-oxidized ATP, periodate-oxidized ADP, periodate-oxidized AMP or periodate-oxidized adenosine, the first phase of contraction to submaximal ATP concentrations was potentiated. Simultaneously, periodate-oxidized ATP, periodate-oxidized ADP and periodate-oxidized AMP inhibited the second contractile phase, whereas periodate-oxidized adenosine did not. The results indicate that the requirement for 5'-phosphate to produce potentiation and inhibition is different: 5'-phosphate is not needed to potentiate the first phase of contraction to ATP, but at least one 5'-phosphate is required to inhibit the second phase of contraction.
先前的研究表明，用亲和标记高碘酸盐氧化的ATP（2',3'-二醛ATP）处理豚鼠离体输精管，会对ATP的双相收缩反应产生两种不可逆的影响，即增强P2X嘌呤受体介导的第一相反应并抑制胞外激酶介导的第二相反应。本实验旨在评估高碘酸盐氧化的ADP、高碘酸盐氧化的AMP和高碘酸盐氧化的腺苷是否产生类似的效果。高碘酸盐氧化的ATP和高碘酸盐氧化的ADP（10⁻² M）引起输精管收缩（高碘酸盐氧化的ATP > 高碘酸盐氧化的ADP；高碘酸盐氧化的AMP和高碘酸盐氧化的腺苷无激动剂活性）。将标本用10⁻² M高碘酸盐氧化的ATP、高碘酸盐氧化的ADP、高碘酸盐氧化的AMP或高碘酸盐氧化腺苷孵育5分钟后，对亚最大ATP浓度的第一相收缩反应增强。同时，高碘酸盐氧化的ATP、高碘酸盐氧化的ADP和高碘酸盐氧化的AMP抑制第二收缩相，而高碘酸盐氧化的腺苷则无此作用。结果表明，产生增强和抑制作用对5'-磷酸基团的需求不同：增强对ATP的第一相收缩反应不需要5'-磷酸基团，但抑制第二相收缩至少需要一个5'-磷酸基团。
