Conduction systems controlling expansion‐contraction behavior in the sea pen<i>Ptilosarcus gurneyi</i>

Dickinson, Patsy S.

doi:10.1080/10236247809378532

Cited by 13 publications

(7 citation statements)

References 37 publications

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“…Experiments undertaken to determine if there exists any daily rhythmicity in muscle or bioluminescence activities of the colony yielded negative results (Anctil et al, 1991 and personal observations). A daily rhythmic activity has previously been reported in a sea pen related to the sea pansy (Imafuku, 1973), but not in another (Dickinson, 1978). Thus, although the presence of daily rhythmicity in the sea pansy cannot be ruled out, the photocycle does not seem to be involved in coordinating any of its major activities.…”

Section: Discussionmentioning

confidence: 81%

Melatonin in a primitive metazoan: Seasonal changes of levels and immunohistochemical visualization in neurons

Mechawar

Anctil

1997

J. Comp. Neurol.

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Monthly day/night melatonin activity profiles were determined by radioimmunoassay over a 13-month period in the colonial anthozoan Renilla köllikeri, and no daily rhythmic oscillation was found. Averaging those monthly values yielded a seasonal quantitative rhythm in both colonial and non-colonial tissues of this cnidarian, with spring and summer levels found to be four to five times higher than autumn and winter ones. The annual rise, which occurred in two successive Aprils, coincided with the first stages of sexual maturation in R. köllikeri. Immunohistochemistry with a melatonin antibody raised in sheep revealed an exclusively neuronal distribution of melatonin-immunoreactivity (MEL-IR) in the endodermal septal filaments wrapped around gametophores, in endodermal walls of the rachis, and in the ectoderm of polyps. The MEL-IR ectodermal neurons shared many morphological features with serotonin-immunoreactive (5-HT-IR) neurons previously described in this animal but showed either weak or absent 5-HT-IR in double-labelling experiments. In contrast, MEL-IR and 5-HT-IR were strongly colocalized in endodermal neurons. These results indicate that melatonin is not a daily photoperiodic messenger but may instead act as a seasonal marker for reproduction in this cnidarian. We also provide the first evidence of a neuronal localisation of melatonin in an invertebrate, which suggests that melatonin may act as a neurotransmitter or neurohormone in the least evolved animals endowed with a nervous system.

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Section: Discussionmentioning

confidence: 81%

Melatonin in a primitive metazoan: Seasonal changes of levels and immunohistochemical visualization in neurons

Mechawar

Anctil

1997

J. Comp. Neurol.

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“…These data suggest a possible loose interaction between the two systems, especially in Acanthoptilum where the two systems usually fail together. Additional evidence for a NN-BP interaction was found in Ptilosarcus where the stimulus-to-response delay for BP impulses was greater when the NN impulses were not activated (Dickinson, 1978).…”

Section: Discussionmentioning

confidence: 95%

“…Mackie and Passano, 1968); (3) the variations in activity spread and conduction velocity are generally attributed to the activation or inactivation of junctions within the conducting system, producing either more direct or more tortuous pathways. The second conduction system (BP system) of the slow pennatulids is not associated with any obvious behavioral activities, although Dickinson (1978) presents evidence that it may be involved in colony relaxation (inflation) in Ptilosarcus. This function parallels that of the anemone and hexacoral "slow" systems (McFarlane, 1969(McFarlane, , 1978Shelton, 1965a;Shelton and McFarlane, 1976a, b).…”

Section: Discussionmentioning

confidence: 98%

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Colonial coordination in anthozoans: Pennatulacea†

Satterlie

Anderson

Case

1980

Marine Behaviour and Physiology

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Morphological and physiological evidence from five species of pennatulid octocorals indicates that a through-conducting colonial nerve net controls colony-wide responses including polyp withdrawal, bioluminescence and rachidial contraction. This nerve net is synaptic, and located in the ectoderm and mesoglea of the colonial tissue. Nerve net impulses recorded extracellularly, show initial increases in conduction velocity during repetitive stimulation which promote faci'ation of effectors. The response-amplitude of these effectors is frequency dependent. Bridge experiments suggest that interneural facilitation may contribute to the conduction velocity changes. Photometric measurements with concurrent electrophysiological recordings reveal that bioluminescence is under the control of the colonial nerve net. Luminescent responses show a frequency-dependent facilitation similar to that of other effectors. These physiological data, together with morphological data on the location and shape of autozooid photocytes suggest that the photocytes may be modified circular or radial muscle cells. A second through-conducting colonial system was detected in three pennatulid species, the function of this system, however, was not evident.

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“…These otherwise sessile invertebrates can withdraw completely into the sediment on an apparently rhythmic but unsynchronized schedule. 1963, Buisson 1964, Pavans de Ceccatty and Buisson 1965, Magnus 1966, Wilson 1975, Imafuku 1976, Hoare and Wilson 1977, Dickinson 1978. 1963, Buisson 1964, Pavans de Ceccatty and Buisson 1965, Magnus 1966, Wilson 1975, Imafuku 1976, Hoare and Wilson 1977, Dickinson 1978.…”

Section: Discussionmentioning

confidence: 99%

Distribution, behavior and abundance of sea pens,Pennatula aculeata, in the Gulf of Maine

Langton

Theroux

et al. 1990

Mar. Biol.

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Sea pens, particularly Pennatula aculeata Danielssen, are major components of the megafauna in the Gulf of Maine, USA. A review of three separate collections (National Marine Fisheries Service, Woods Hole; University of Maine; Smithsonian Institution), as well as recent submersible and remotely operated vehicle survey work, have shown that this single species is fairly ubiquitous. It is, however, more prevalent in the eastern part of the Gulf and is almost absent from Wilkinson Basin in the west. The spatial distribution of sea pens was photographically documented on four submersible dive transects in the eastern and central Gulf of Maine in 1983. The degree of contagion of sea pen populations was evaluated using the variance-to-mean ratio and Morisita's index of dispersion. In all cases these indices were > 1, suggesting a contagious distribution. Both Poisson and negative binomial probability distributions were fitted to the data. The negative binomial was the best descriptor of the distributions on three transects. On one transect, neither distributional model had a significant fit at the 5% level. The effect of quadrat size on these distributions was assessed for three quadrat sizes (7, 3, and 1.24m2). The pattern for the smallest quadrat size showed a significant fit to both Poisson and negative binomial distributions, while the Poisson distribution did not fit the data for the larger quadrats. The density of sea pens in individual photographs varied from 0 to 8 m-2 in Georges Basin, but density estimates were slightly confounded by the ability of sea pens to withdraw into their burrows, completely below the sediment surface. Behavioral observations in situ on Jeffreys Bank in 1986 were made using a manned submersible to observe the withdrawal and extension of specified sea pens. Seventeen sea pens were monitored on five dives over 24 h; two specimens withdrew completely, and another individual extended from a fully withdrawn position. During the observation period, 88% of the sea pens remained fully extended.

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Conduction systems controlling expansion‐contraction behavior in the sea penPtilosarcus gurneyi

Cited by 13 publications

References 37 publications

Melatonin in a primitive metazoan: Seasonal changes of levels and immunohistochemical visualization in neurons

Melatonin in a primitive metazoan: Seasonal changes of levels and immunohistochemical visualization in neurons

Colonial coordination in anthozoans: Pennatulacea†

Distribution, behavior and abundance of sea pens,Pennatula aculeata, in the Gulf of Maine

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