Bize I, Santander G
J Exp Zool. 1985 Aug;235(2):261-7. doi: 10.1002/jez.1402350213.
We have investigated the possibility of an interaction between epinephrine and external potassium in the stimulation of the hamster sperm acrosome reaction and in vitro fertilizing ability. We have found that: 1) K+ is required late in capacitation and/or the acrosome reaction, but is not required for penetration of the zona pellucidae, 2) the presence of epinephrine (50 microM) in the capacitation medium lowers the K+ requirements of these processes and 3) furosemide, a cotransport inhibitor, blocks the acrosome reaction, in vitro fertilization, and inhibits the stimulation by epinephrine. These results support the idea that there is an interaction between epinephrine as a stimulus to the secretion of the acrosomal content, and K+ as a mediator of the stimulus signal. They further suggest that K+ influx through the cotransport mechanism occurs during capacitation, that this mechanism is activated late during the process, and that it probably mediates the stimulatory effects of epinephrine. We would like to propose that the activation of passive cation transport mechanisms is a general phenomenon in biological signal transduction.
我们研究了肾上腺素与细胞外钾离子在刺激仓鼠精子顶体反应及体外受精能力方面相互作用的可能性。我们发现：1）钾离子在获能后期和/或顶体反应中是必需的，但穿透透明带则不需要；2）获能培养基中存在肾上腺素（50微摩尔）可降低这些过程对钾离子的需求；3）呋塞米，一种协同转运抑制剂，可阻断顶体反应、体外受精，并抑制肾上腺素的刺激作用。这些结果支持这样一种观点，即作为顶体内容物分泌刺激物的肾上腺素与作为刺激信号介导物的钾离子之间存在相互作用。它们进一步表明，在获能过程中通过协同转运机制发生钾离子内流，该机制在过程后期被激活，并且它可能介导肾上腺素的刺激作用。我们提出被动阳离子转运机制的激活是生物信号转导中的一种普遍现象。
