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Cell and Tissue Research

, Volume 284, Issue 2, pp 279–288 | Cite as

Structure of the aesthetasc (olfactory) sensilla of the blue crab, Callinectes sapidus: transformations as a function of salinity

  • Richard A. Gleeson
  • Lorraine M. McDowell
  • Henry C. Aldrich

Abstract.

The aesthetasc sensilla of the euryhaline blue crab, Callinectes sapidus, are innervated by the dendrites of from 40 to 160 bipolar chemosensory neurons. Each dendrite forms two cilia within the basal portion of the sensillum, and these subsequently branch yielding approximately 10 outer dendritic segments per neuron. Auxiliary cells surround the inner dendritic segments and also ensheathe the outer dendritic segments up to the terminus of the ”constricted region” (a zone in which there is a slight narrowing of the aesthetasc). Crystal violet staining suggesting access of odor stimuli is limited to that portion of the sensillum distal to the constricted region. In freshwater-acclimated blue crabs the length and level of branching in the dendrites extending beyond the constricted region is significantly reduced relative to that of seawater-acclimated animals (mean lengths: 150 µm versus 517 µm, respectively). After transfer of freshwater-acclimated crabs to seawater there is a rapid increase in length of the outer dendritic segments, reaching 60% of that for seawater-acclimated crabs by 48 h. A similar time course for regrowth is seen for seawater-acclimated crabs in which the outer dendritic segments have been osmotically ablated. Conversely, with rapid transfer of seawater-acclimated animals to lower salinities, there is a correspondingly rapid reduction in length of the outer dendritic segments. The reduced length of the outer dendritic segments in freshwater-acclimated animals may reflect the effective distance over which an appropriate osmotic/ionic microenvironment for neural function can be maintained within the aesthetasc.

Key words: Aesthetasc Chemoreception Dendrite Blue crab growth Olfaction Salinity adaptation Sensilla Callinectes sapidus (Crustacea) 

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Copyright information

© Springer-Verlag Berlin Heidelberg 1996

Authors and Affiliations

  • Richard A. Gleeson
    • 1
  • Lorraine M. McDowell
    • 2
  • Henry C. Aldrich
    • 2
  1. 1.The Whitney Laboratory, University of Florida, 9505 Ocean Shore Blvd., St. Augustine, Florida 32086, USAUS
  2. 2.Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida 32611, USAUS

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