title: Neuroanatomy of the tube feet and tentacles in Holothuria glaberrima (Holothuroidea, Echinodermata).
abstract: Echinoderms are a key group in understanding the evolution of the nervous system in the Metazoa. Remarkably, little is known about echinoderm neurobiology. The echinoderm podia, which are unique echinoderm modifications and comprise structures responsible for locomotion and feeding, have been largely neglected in nervous system studies. Here, we have applied immunohistological approaches using different neuronal markers to describe the neuroanatomy of the holothurian podia and its relation to the muscular component. We show, using the sea cucumber Holothuria glaberrima (Selenka, 1867), the direct innervation of the podia by the ectoneural component of the nervous system, as well as the existence of a connection between the nervous system components in the main nerves, the muscle, and the connective tissue. These findings confirm the ectoneural origin of the tube feet's main nervous system and demonstrate its neuroanatomic complexity. We also show the presence of fibers and neurons within the tube feet mesothelium and connective tissue. The study of these simple structures will help us elucidate the echinoderms' neuromuscular circuit and their evolutionary relationships.
authors.affiliation: Department of Biology, University of Puerto Rico, Río Piedras Campus, Box 23360, Río Piedras, Puerto Rico 00931-3360.
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Díaz-Balzac
authors.forename: José E
authors.initials: JE
authors.lastname: Abreu-Arbelo
authors.forename: José E
authors.initials: JE
authors.lastname: García-Arrarás
references.citation: Biol Bull. 2007 Aug;213(1):28-42
references.pmid: 17679718
references.citation: Biol Rev Camb Philos Soc. 1972 Aug;47(3):363-92
references.pmid: 4563848
references.citation: Cell Tissue Res. 1977 Feb 9;177(2):195-214
references.pmid: 837407
references.citation: Cell Tissue Res. 1981;218(3):449-73
references.pmid: 7196287
references.citation: Cell Tissue Res. 1993 Dec;274(3):605-18
references.pmid: 8293452
references.citation: Biol Bull. 1996 Aug;191(1):1-4
references.pmid: 8776839
references.citation: Cell Tissue Res. 1982;224(3):543-51
references.pmid: 7116411
references.citation: Cell Tissue Res. 1996 Dec;286(3):385-91
references.pmid: 8929341
references.citation: J Comp Neurol. 1999 Apr 19;406(4):461-75
references.pmid: 10205023
references.citation: J Exp Biol. 2001 Mar;204(Pt 5):865-73
references.pmid: 11171410
references.citation: Cell Tissue Res. 1981;218(3):475-85
references.pmid: 7196288
references.citation: J Exp Biol. 2005 Jun;208(Pt 12):2277-88
references.pmid: 15939770
references.citation: Dev Biol. 2006 Dec 1;300(1):434-60
references.pmid: 16965768
references.citation: Science. 2006 Nov 10;314(5801):941-52
references.pmid: 17095691
references.citation: Biol Bull. 1998 Jun;194(3):253-9
references.pmid: 9664654
references.citation: J Morphol. 2006 Jan;267(1):41-9
references.pmid: 16240387
references.citation: Proc Biol Sci. 2007 Sep 22;274(1623):2279-85
references.pmid: 17623636
references.citation: J Comp Neurol. 2006 May 10;496(2):244-51
references.pmid: 16538680
references.citation: J Comp Neurol. 1995 Feb 20;352(4):626-40
references.pmid: 7722004
references.citation: Dev Biol. 2002 Oct 1;250(1):181-97
references.pmid: 12297105
references.citation: Evol Dev. 2004 Mar-Apr;6(2):95-104
references.pmid: 15009122