Scholz N L, de Vente J, Truman J W, Graubard K
University of Washington, Department of Zoology, Seattle, Washington 98195-1800, USA.
J Neurosci. 2001 Mar 1;21(5):1610-8. doi: 10.1523/JNEUROSCI.21-05-01610.2001.
The stomatogastric ganglion (STG) of the crab Cancer productus contains approximately 30 neurons arrayed into two different networks (gastric mill and pyloric), each of which produces a distinct motor pattern in vitro. Here we show that the functional division of the STG into these two networks requires intact NO-cGMP signaling. Multiple nitric oxide synthase (NOS)-like proteins are expressed in the stomatogastric nervous system, and NO appears to be released as an orthograde transmitter from descending inputs to the STG. The receptor of NO, a soluble guanylate cyclase (sGC), is expressed in a subset of neurons in both motor networks. When NO diffusion or sGC activation are blocked within the ganglion, the two networks combine into a single conjoint circuit. The gastric mill motor rhythm breaks down, and several gastric neurons pattern switch and begin firing in pyloric time. The functional reorganization of the STG is both rapid and reversible, and the gastric mill motor rhythm is restored when the ganglion is returned to normal saline. Finally, pharmacological manipulations of the NO-cGMP pathway are ineffective when descending modulatory inputs to the STG are blocked. This suggests that the NO-cGMP pathway may interact with other biochemical cascades to partition rhythmic motor output from the ganglion.
太平洋岩蟹的口胃神经节（STG）包含大约30个神经元，这些神经元排列成两个不同的网络（胃磨和幽门），每个网络在体外都会产生独特的运动模式。我们在此表明，STG功能上划分为这两个网络需要完整的一氧化氮 - 环磷酸鸟苷（NO - cGMP）信号传导。多种一氧化氮合酶（NOS）样蛋白在口胃神经系统中表达，并且NO似乎作为顺行递质从下行输入释放到STG。NO的受体，可溶性鸟苷酸环化酶（sGC），在两个运动网络的一部分神经元中表达。当神经节内的NO扩散或sGC激活被阻断时，这两个网络合并成一个单一的联合回路。胃磨运动节律瓦解，并且几个胃神经元的模式转换并开始按幽门节律放电。STG的功能重组既迅速又可逆，当神经节放回正常盐溶液中时，胃磨运动节律得以恢复。最后，当对STG的下行调节输入被阻断时，对NO - cGMP途径的药理学操作无效。这表明NO - cGMP途径可能与其他生化级联反应相互作用，以分配来自神经节的节律性运动输出。
