Facultad de Veterinaria, Departamento de Bioquímica, Universidad Complutense, Madrid, Spain.
J Cell Physiol. 2012 May;227(5):2252-63. doi: 10.1002/jcp.22964.
Cyclic nucleotide-gated channels (CNGCs) are important transducers of external signals in sensory processes. These channels are ubiquitously expressed in a variety of neurons, and are necessary to transduce signals for growth cone guidance and plasticity. Here, we demonstrate that the CNGC subunits (CNGA1 and CNGB1, presumably the 1b isoform) are expressed in rat cerebellar granule cells and that they combine to form functional channels. The expression of the mRNAs that encode these proteins is maximal after 7 days in cell culture, when the channels are expressed at synapses and co-localize with the synaptic marker synapsin I. These ligand-gated channels are functional and can be blocked by Mg(2+) or L-cis-diltiazem. Moreover, channel opening in response to increases in intracellular cGMP results in Ca(2+) entry into the cell. Chronic blockade (96 h) of these channels with L-cis-diltiazem significantly decreases the number of functional boutons, as determined by their capacity to load and unload the styryl dye FM1-43 when stimulated. Moreover, the unloading kinetics is modified from a biphasic to a monophasic profile in a subset of synaptic boutons. These channels are also expressed in early developmental stages, both in the soma and in emerging processes, and CNGA1 can be detected in growth cones. Pharmacological blockade of these channels with L-cis-diltiazem causes an overall change in growth cone morphology, impairing the formation of lamellipodia between filopodia and increasing the number of filopodia. J
环核苷酸门控通道（CNGCs）是感觉过程中外部信号的重要转导器。这些通道在各种神经元中广泛表达，对于生长锥导向和可塑性的信号转导是必需的。在这里，我们证明 CNGC 亚基（CNGA1 和 CNGB1，推测为 1b 同工型）在大鼠小脑颗粒细胞中表达，并且它们组合形成功能性通道。这些蛋白编码的 mRNA 的表达在细胞培养 7 天后达到最大值，此时通道在突触处表达并与突触标记物突触素 I 共定位。这些配体门控通道是功能性的，可以被 Mg2+或 L-cis-二氢异搏定阻断。此外，细胞内 cGMP 增加引起的通道开放导致 Ca2+进入细胞。用 L-cis-二氢异搏定慢性阻断（96 h）这些通道会显著减少功能性末梢的数量，这可以通过它们在刺激时加载和卸载 styryl 染料 FM1-43 的能力来确定。此外，在一部分突触末梢中，卸载动力学从双相变为单相。这些通道也在早期发育阶段表达，无论是在胞体还是在新出现的突起中，并且可以在生长锥中检测到 CNGA1。用 L-cis-二氢异搏定阻断这些通道会导致生长锥形态发生整体变化，损害了丝状伪足之间的板层伪足的形成，并增加了丝状伪足的数量。
