Mechanisms of peptidergic regulation of muscle movements in molluscs.

1.从非洲大蜗牛Achatinafulica的中枢神经系统、心脏和颊肌中分离到二十多种兴奋性或抑制性神经肽。其中，对FMRFamide、ACEP-1、achatin-I和fulicin的功能和分布进行了研究.免疫组织化学研究表明，FMRFamide和ACEP-1样物质在脑神经节、食管下神经节、神经丛、肠心神经和心房的许多神经元中都有丰富的分布。但心室几乎没有这些在神经节中合成的肽很可能被转运到心房中的神经纤维，然后释放到心室，在那里它们发挥作用。与颊肌运动有关的两对脑神经节神经元和十对颊神经节神经元已被鉴定，并对其形态和功能进行了研究。其中有两种制度是比较有特色的。一个;由胆碱能运动神经元B4的放电引起的齿舌牵开器的收缩由胆碱能神经元v-CDN兴奋性地调节。另一个;胆碱能运动神经元B10含有神经肽ACEP-1，齿舌延长肌的收缩受ACEP-1的调节，ACEP-1可能在突触前作用于神经末梢以增加ACh的释放。以鸡阴茎缩肌为生物活性测定系统，研究了Fulicin的构效关系，并对Fulicin在鸡阴茎缩肌中的分布和定位进行了化学分析。结果表明，富里霉素在生理上参与调节阴茎收缩肌的收缩。

1. More than twenty kinds of excitatory or inhibitory neuropeptides have been isolated from the central nervous system, heart and buccal muscles of the African giant snail Achatina fulica. Among them, the function and distribution of FMRFamide, ACEP-1, achatin-I and fulicin were investigated.2. Although FMRFamide, ACEP-1 and achain-I were isolated from the atria of this animal, they did not show any significant direct effects on the atrium but did show strong excitatory effects on the ventricle.Immunohistochemical investigation has revealed that FMRFamide- and ACEP-1-like substances are richly distributed in many neurons in the cerebral and subesophageal ganglia, neuropile, intestinal nerve going to the heart, and atrium, but very scarcely in the ventricle. It is probable that these peptides synthesized in the ganglia are transported to the nerve fibers in the atrium and then released to the ventricle where they exhibit their actions.3. In relation to the buccal muscle movements, two pairs of cerebral ganglionic neurons and ten pairs of buccal ganglionic neurons have been identified and their morphology and function have been investigated. Among them two systems are characteristic. One; the contraction of the radula retractor elicited by the firing of cholinergic motoneuron B4 is modulated excitatorily by serotonergic neuron v-CDN. The other; a cholinergic motoneuron B10 contains neuropeptide ACEP-1, and the contraction of the radula protractor is modulated by ACEP-1 possibly acting presynaptically to the nerve terminals to increase the release of ACh.4. Structure-activity relationships of fulicin were studied by using the penis retractor muscle as a bioassay system, and the distribution and localization of this peptide were investigated immunohistochemically. It was concluded that fulicin is involved physiologically in the regulation of contraction of the penis retractor muscle.