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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
2000-4-12
pubmed:abstractText
Previous research suggests that a major role of the apical ganglion (also called the apical or cephalic sensory organ) in gastropod larvae is detection and integration of sensory information and relay of motor signals to effectors in the velum. However, the relative impact of ancestry versus velum size and life history on characteristics of the apical ganglion is unresolved. We address this issue by contributing data on the apical ganglion and overlying epidermis in planktotrophic larvae of four caenogastropod species (Euspira [Polinices] lewisii, Lacuna vincta, Trichotropis cancellata, and Amphissa versicolor) derived from light microscopy, scanning and transmission electron microscopy, and immunohistochemical localization of serotonin-like antigenicity. Ultrastructure of the apical ganglion is similar in these caenogastropods, and the basic plan corresponds to previous descriptions of the apical ganglion in planktotrophic opisthobranch larvae (subgroup of Heterobranchia). The only identified structural feature that is unique to all these caenogastropods, relative to opisthobranchs, is modified ciliary axonemes for the ampullary cells, a distinctive type of sensory neuron. Like opisthobranch larvae, caenogastropod larvae have serotonin-immunoreactive neurons within the apical ganglion; the number ranges from three to six, but a lateral pair of serotonergic, nonsensory neurons is common to all species. The pattern of serotonergic neurons in E. lewisii, which develops large, subdivided velar lobes, is the same as that of opisthobranch larvae, which have a relatively small, unelaborated velum. These and other data suggest that common ancestry is a major determinant of overall structural design for the apical ganglion in caenogastropods and heterobranchs, which are sister groups within the Gastropoda. Velum size and life history strategy may account for some, but not all, cases of interspecific differences in the serotonergic component.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0021-9967
pubmed:author
pubmed:copyrightInfo
Copyright 2000 Wiley-Liss, Inc.
pubmed:issnType
Print
pubmed:day
20
pubmed:volume
418
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
383-401
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2000
pubmed:articleTitle
Comparative study of the apical ganglion in planktotrophic caenogastropod larvae: ultrastructure and immunoreactivity to serotonin.
pubmed:affiliation
Department of Biology, University of Victoria, British Columbia V8W 3N5, Canada. lpage@uvvm.uvic.ca
pubmed:publicationType
Journal Article, Comparative Study, Research Support, Non-U.S. Gov't