Neuropeptide Localization in Lymnaea stagnalis: From the Central Nervous System to Subcellular Compartments.

Linwen Zhang,Zsolt Pirger,Gabor Maasz,Sylwia A Stopka,Ellen A Wood,Akos Vertes,Sara Mattson

doi:10.3389/fnmol.2021.670303

Abstract

Due to the relatively small number of neurons (few tens of thousands), the well-established multipurpose model organism Lymnaea stagnalis, great pond snail, has been extensively used to study the functioning of the nervous system. Unlike the more complex brains of higher organisms, L. stagnalis has a relatively simple central nervous system (CNS) with well-defined circuits (e.g., feeding, locomotion, learning, and memory) and identified individual neurons (e.g., cerebral giant cell, CGC), which generate behavioral patterns. Accumulating information from electrophysiological experiments maps the network of neuronal connections and the neuronal circuits responsible for basic life functions. Chemical signaling between synaptic-coupled neurons is underpinned by neurotransmitters and neuropeptides. This review looks at the rapidly expanding contributions of mass spectrometry (MS) to neuropeptide discovery and identification at different granularity of CNS organization. Abundances and distributions of neuropeptides in the whole CNS, eleven interconnected ganglia, neuronal clusters, single neurons, and subcellular compartments are captured by MS imaging and single cell analysis techniques. Combining neuropeptide expression and electrophysiological data, and aided by genomic and transcriptomic information, the molecular basis of CNS-controlled biological functions is increasingly revealed.

Highlights

Neuropeptides in Lymnaea stagnalisLymnaea stagnalis, known as the great pond snail, is an excellent model organism used for research in neuroscience, aging, ecotoxicology, parasite-host interactions, and evolution and development (Jimenez et al, 2004; Hoek et al, 2005; Benjamin, 2008; Pirger et al, 2014; Fodor et al, 2020a,b, 2021)
It is composed of eleven interconnected ganglia, each containing their own unique sub-populations of large and brightly colored neurons with specific functions and Neuropeptide Localization in Lymnaea stagnalis expressing a set of neuropeptides, as shown in Figure 1 (Benjamin and Kemenes, 2013; Rivi et al, 2020)
From the early 1980s, neuropeptides have become a focal point for research due to their direct role in modulating neuronal circuit functions within the central nervous system (CNS) (Schot et al, 1981; Patel et al, 2005)

Summary

Introduction

Neuropeptides in Lymnaea stagnalisLymnaea stagnalis, known as the great pond snail, is an excellent model organism used for research in neuroscience, aging, ecotoxicology, parasite-host interactions, and evolution and development (Jimenez et al, 2004; Hoek et al, 2005; Benjamin, 2008; Pirger et al, 2014; Fodor et al, 2020a,b, 2021). In the early 1990s, single cell level molecular analysis was enabled by the large size of some neurons (>50 μm) readily accessible in L. stagnalis and the emerging high spatial resolution and sensitivity of mass spectrometry (MS). Following the multilevel approach (from behavior to circuits, and molecules) in L. stagnalis research, Figure 2 shows the four levels of organization in the CNS, the corresponding mass spectra, and the localization of some neuropeptides.

Results

Conclusion