Neuromuscular organization of the Ctenophore Pleurobrachia bachei. Issue 2 (17th November 2018)

• Record Type: Journal Article
• Authors: Norekian, Tigran P.; Moroz, Leonid L.
• Is Part Of: Journal of comparative neurology. Volume 527:Issue 2(2019)
• Page Start: 406
• Page End: 436
• Publication Date: 2018-11-17
• Subjects: apical organ -- Beroe -- cell atlas -- cilia -- Ctenophora -- development -- evolution -- F‐actin -- feeding -- mesoglea -- microvilli -- Mnemiopsis -- muscle system -- nervous system -- phylogeny -- RRID:AB_325003 -- RRID:AB_141373 -- RRID:AB_2534121 -- sensory cells -- Stereocilia -- tubulin; Comparative neurobiology -- Periodicals; Neurology -- Periodicals; 616
• DOI: 10.1002/cne.24546
• Languages: English
• ISSNs: 0021-9967

Abstract

Abstract: Ctenophores are descendants of one of the earliest branching metazoan lineage with enigmatic nervous systems. The lack of convenient neurogenic molecules and neurotransmitters suggests an extensive parallel evolution and independent origins of neurons and synapses. However, the field lags due to the lack of microanatomical data about the neuro‐muscular systems in this group of animals. Here, using immunohistochemistry and scanning electron microscopy, we describe the organization of both muscular and nervous systems in the sea gooseberry, Pleurobrachia bachei, from North Pacific. The diffuse neural system of Pleurobrachia consists of two subsystems: the subepithelial neural network and the mesogleal net with about 5, 000–7, 000 neurons combined. Our data revealed the unexpected complexity of neuromuscular organization in this basal metazoan lineage. The anatomical diversity of cell types includes at least nine broad categories of neurons, five families of surface receptors and more than two dozen types of muscle cells as well as regional concentrations of neuronal elements to support ctenophore feeding, complex swimming, escape, and prey capture behaviors. In summary, we recognize more than 80 total morphological cell types. Thus, in terms of cell‐type specification and diversity, ctenophores significantly exceed what we currently know about other prebilaterian groups (placozoan, sponges, and cnidarians), and some basal bilaterians. Abstract : Comb jellies or ctenophores might evolve independently their neurons and synapses. However, the field lags due to the lack of microanatomical data about the neuro‐muscular systems in this group of animals. Here, using immunohistochemistry and scanning electron microscopy, we describe the organization of both muscular and nervous systems in the sea gooseberry, Pleurobrachia bachei, from North Pacific. The diffuse neural system of Pleurobrachia consists of two subsystems: the subepithelial neural network and the mesogleal net with about 5, 000–7, 000 neurons combined. In terms of cell type specification and diversity, ctenophores significantly exceed what we currently know about other prebilaterian groups, and even some basal bilaterians. The revealed unprecedented complexity of neuromuscular organization and receptors in this basal metazoan lineage supports complex ctenophore feeding, swimming, escape and prey capture behaviors.