Regulation of rhythmic movements by purinergic neurotransmitters in frog embryos
Regulation of rhythmic movements by purinergic neurotransmitters in frog embryos
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DOI：
10.1038/383259a0
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发表时间：
1996-09-19
期刊：
影响因子：
64.8
通讯作者：
Gilday, D
中科院分区：
文献类型：
--
作者：
Dale, N;Gilday, D
许多有节奏的运动行为，包括游泳(1)、走路(2)、抓挠(3)、吞咽(4)、排尿(5)和性高潮(6)，都是偶发性的：即使在没有感觉输入的情况下，它们在自发终止之前也会逐渐减少频率。我们已经研究了嘌呤能递质，ATP和腺苷是否控制爪蟾胚胎的游泳能力下降(7)。通过使用嘌呤能受体的特异性激动剂和拮抗剂，我们已经证明ATP（或相关物质）在游泳过程中释放并激活P2y受体，以减少电压门控K+电流，并导致脊髓运动回路的兴奋性增加。腺苷也在运动活动中产生，可能是通过外核苷酶的作用。腺苷对P1受体的激活降低了电压门控Ca2+电流，降低了运动回路的兴奋性，从而反对ATP的作用。因此，ATP和腺苷之间逐渐改变的平衡似乎是非洲爪蟾游泳运动模式失效的基础。我们认为这是第一次发现ATP和腺苷参与运动模式，这两者可能提供了一种普遍的反馈机制，这是脊椎动物所有偶发性运动模式的基础。
MANY rhythmic motor behaviours, including swimming(1), walking(2) scratching(3), swallowing(4), micturition(5) and sexual climax(6), are episodic: even in the absence of sensory inputs they exhibit a gradual run-down in frequency before spontaneously terminating. We have investigated whether the purinergic transmitters, ATP and adenosine, control run-down of swimming in the Xenopus embryo(7). By using specific agonists and antagonists for the purinergic receptors, we have shown that ATP (or a related substance) is released during swimming and activates P2y receptors to reduce voltage-gated K+ currents and cause an increase in the excitability of the spinal motor circuits. Adenosine is also produced during motor activity, possibly through the actions of ectonucleotidases. The activation by adenosine of P1 receptors reduces the voltage-gated Ca2+ currents, lowers excitability of the motor circuits, and so opposes the actions of ATP. A gradually changing balance between ATP and adenosine therefore seems to underlie the run-down of the motor pattern for swimming in Xenopus. We believe this to be the first time that ATP and adenosine have been found to be involved in motor pattern these two may offer a general feedback mechanism that underlies run down of all episodic motor patterns in vertebrates.