Lloyd P E
Fed Proc. 1982 Nov;41(13):2948-52.
At least five neuropeptides that are active on an isolated snail heart can be recovered from extracts of gastropod nervous tissue. These peptides have been divided into three classes. The class of the lowest molecular weight, termed the small cardioactive peptides (SCPs), is made up of two peptides. SCPs have been found in all gastropods studied and appear to be involved in the control of the gut. They have been localized by microdissection and bioassay to several identified central neurons that send their axons out to innervate the gut. These neurons act centrally to enhance the motor output of the ganglia responsible for the control of feeding, and peripherally to modulate gut activity. In one pair of these neurons, the classical transmitter acetylcholine coexists with an SCP. The next larger peptide class (medium cardioactive peptide), found only in Aplysia, shares both its mode of cardiac activity and tissue distribution with the SCPs. As yet, there is no evidence that either of these peptide classes acts as a physiological modulator of cardiac activity. The class of the highest molecular weight (large cardioactive peptide [LCPs]) is made up of two peptides and is found only in Helix. The LCPs are circulating neurohormones involved in the regulation of heart, gut, and neuromuscular activity. Their primary release site is a neurohemal region in the auricle. The significance of these findings is discussed in light of recent advances in the study of mammalian neuropeptides.
从腹足纲动物神经组织提取物中可分离出至少五种对离体蜗牛心脏有活性的神经肽。这些肽已被分为三类。分子量最低的一类，称为小的心脏活性肽（SCPs），由两种肽组成。在所有已研究的腹足纲动物中都发现了SCPs，它们似乎参与肠道的控制。通过显微解剖和生物测定法已确定，有几个特定的中枢神经元可产生SCPs，这些神经元的轴突向外延伸支配肠道。这些神经元在中枢发挥作用，增强负责控制进食的神经节的运动输出，在周围则调节肠道活动。在其中一对这样的神经元中，经典递质乙酰胆碱与一种SCP共存。下一个较大的肽类（中等心脏活性肽）仅在海兔中发现，其心脏活动模式和组织分布与SCPs相同。目前，尚无证据表明这两类肽中的任何一种可作为心脏活动的生理调节因子。分子量最高的一类（大的心脏活性肽[LCPs]）由两种肽组成，仅在螺旋蜗牛中发现。LCPs是参与调节心脏、肠道和神经肌肉活动的循环神经激素。它们的主要释放部位是心耳中的一个神经血区。结合哺乳动物神经肽研究的最新进展，对这些发现的意义进行了讨论。
