Laboratory of Neurobiology, International College of Arts and Sciences, Fukuoka Women's University, 1-1-1 Kasumigaoka, Higashi-ku, Fukuoka, 813-8529, Japan.
Kagawa School of Pharmaceutical Sciences, Tokushima Bunri University, 1314-1 Shido, Sanuki, Kagawa, 769-2193, Japan.
J Comp Physiol A Neuroethol Sens Neural Behav Physiol. 2020 May;206(3):401-418. doi: 10.1007/s00359-020-01400-2. Epub 2020 Jan 29.
In gastropods, the function of neuropeptides has been studied primarily in the peripheral motor systems. Their functional roles in the central nervous system have received less attention. The procerebrum, the secondary olfactory center of the terrestrial slug Limax, consists of several hundred thousand interneurons, and plays a pivotal role in olfactory learning and memory. In the present study, we found that enterin, known as a myoactive peptide functioning in the enteric and vascular system of Aplysia, is expressed in the procerebrum of Limax. These enterin-expressing neurons primarily make projections within the cell mass layer of the procerebrum. The oscillatory frequency of the local field potential in the procerebrum was reduced by an exogenous application of enterin. The local field potential oscillation in the tentacular ganglion, the primary olfactory center, was also modulated by enterin. Whole-cell patch-clamp recordings revealed that the modulatory effect in the procerebrum was due to the inhibitory effect of enterin on the bursting neurons, which function as the kernels determining the oscillatory activity of the procerebrum. Our results revealed the novel role of the myoactive neuropeptide enterin in the higher olfactory function in terrestrial gastropods.
在腹足类动物中，神经肽的功能主要在周围运动系统中进行了研究。它们在中枢神经系统中的功能作用受到的关注较少。侧神经节是陆地蜗牛 Limax 的二级嗅觉中枢，由数十万个中间神经元组成，在嗅觉学习和记忆中起着关键作用。在本研究中，我们发现 enterin 在 Aplysia 的肠和血管系统中作为一种肌活性肽发挥作用，在 Limax 的侧神经节中表达。这些表达 enterin 的神经元主要在侧神经节细胞体层内进行投射。外源性应用 enterin 可降低侧神经节局部场电位的振荡频率。触角神经节（初级嗅觉中枢）中的局部场电位振荡也受 enterin 调制。全细胞膜片钳记录显示，侧神经节中的调制作用是由于 enterin 对爆发神经元的抑制作用，这些神经元作为决定侧神经节振荡活动的核心神经元发挥作用。我们的研究结果揭示了肌活性神经肽 enterin 在陆地腹足类动物的高级嗅觉功能中的新作用。
