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Conservation of a T ritonia P edal peptides network in gastropods
Author(s) -
Baltzley Michael J.,
Sherman Allison,
Cain Shaun D.,
Lohmann Kenneth J.
Publication year - 2011
Publication title -
invertebrate biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.486
H-Index - 42
eISSN - 1744-7410
pISSN - 1077-8306
DOI - 10.1111/j.1744-7410.2011.00242.x
Subject(s) - biology , nudibranch , crawling , anatomy , neurite , microbiology and biotechnology , zoology , gastropoda , genetics , in vitro
Adults of the nudibranch mollusc T ritonia diomedea crawl using mucociliary locomotion. Crawling is controlled in part by the large P edal 5 ( Pd5 ) and P edal 6 ( Pd6 ) neurons that produce T ritonia P edal peptides ( TPeps ). TPeps elicit an increase in ciliary beat frequency, thereby increasing crawling speed. In adults of T . diomedea , an extensive network of TPep ‐containing neurites adjacent to the basement membrane of the pedal epithelium delivers TPeps to the ciliated cells. In this study, we show that diverse nudibranchs all have a pattern of TPep ‐like immunoreactivity similar to that of T . diomedea , with thin tracts of TPep ‐like immunoreactive ( TPep ‐ LIR ) neurites projecting to the epithelial layer. We also show that members of two non‐nudibranch gastropod species have a pattern of TPep ‐innervation similar to that of the nudibranchs. In addition, we characterized two pairs of motor neurons in adults of the nudibranch A rmina californica that are possible homologues of the Pd5 and Pd6 cells in T . diomedea . Activity in one of these pairs, the Pedal Peptidergic Dorsal 1 ( PPD 1) cells, was correlated with mucociliary locomotion. The second pair, the Pedal Peptidergic Ventral 1 cells, shared synchronous synaptic input with the PPD 1 cells, a pattern consistent with the shared synaptic input of the T . diomedea Pd5 and Pd6 cells. These findings suggest that the roles of the Pd5 and Pd6 cells as mucociliary motor neurons in nudibranchs are conserved evolutionarily. Additionally, the extensive network of TPep ‐ LIR neurites seen in the foot of T . diomedea appears likely to be a common feature among gastropods.