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Cercariae of Proterometra macrostoma may use catecholamines as endogenous neurotransmitters
Author(s) -
Bumpus Erin Nicole,
Runyan Keith R,
Weitekamp Samuel L,
Bartlow Kathleen Marie
Publication year - 2016
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.30.1_supplement.1228.2
Subject(s) - norepinephrine , catecholamine , neurotransmitter , neuroscience , biology , dopamine , chemistry , endocrinology , central nervous system
Furcocystocercous cercariae of the digenetic trematode parasite Proterametra macrostoma exhibit a characteristic vertical swimming behavior to attract their centrarchid hosts. Previous studies showed that swimming behavior is entirely controlled by the cercarial tail, and may be modulated by factors including light wavelength and mechanical stimulation. We conducted studies using a vertical swim‐up assay to examine the behavioral effects on P. macrostoma cercariae of exogenous application of the catecholamine neurotransmitters dopamine, epinephrine, and norepinephrine. Catecholamine neurotransmitters increased the speed of swimming. Norepinephrine also increased the number of swims per cercaria in a five‐minute period and the time each cercaria spent off the bottom of the water column, implying that behavioral effects of noradrenergic signaling in this species may be ecologically relevant. Studies conducted in whole‐mounted cercariae, using immunofluorescent staining to detect the neuronal marker beta‐III‐tubulin, reveal dense superficial innervation in the posterior cercarial tail in close apposition to striated muscle fibers. Cryosections immunostained for tyrosine hydroxylase (TH) display TH immunoreactivity throughout the distome body and tail of cercariae, particularly in the papillae of the tail, which are thought to be sensory organs. Together, these results suggest that catecholamines are produced and used by P. macrostoma as a neurotransmitter modulating cercarial swimming. Support or Funding Information These studies were funded by the Indiana Academy of Science, and by the following funds associated with Earlham College: Gerald Bakker Collaborative Research Endowment Fund, Matthews Student/Faculty Research in Physics/Biological Science, Harry Todd Costello Fund, Stevenson Fund, and Collaborative Research Fund.