Patterns of serotonin and SCP immunoreactivity during metamorphosis of the nervous system of the red abalone, Haliotis rufescens

Authors

  • Linda A. Barlow,

    Corresponding author
    1. Department of Zoology, University of Washington, Seattle, Washington 98195
    Current affiliation:
    1. Dept. of Neuroscience, University of California at San Diego, La Jolla, CA 92093-0201
    • Department of Zoology, University of Washington, Seattle, Washington 98195
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  • James W. Truman

    1. Department of Zoology, University of Washington, Seattle, Washington 98195
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Abstract

Larvae of the red abalone, Haliotis rufescens, rely on external chemical cues to trigger metamorphosis; thus, the timing of metamorphosis is depedent upon the larva's chance encounter with the appropriate substrate. We examined the effect of the timing of metamorphosis on the development of the central nervous system (CNS), concentrating on the pattern of serotonin and small cardioactive peptide- (SCP) immunopositive neurons in the cerebral ganglia. By 4 days postfertilization the cerebral ganglion has five pairs of serotonin-immunoreactive (IR) neurons, one pair of which (the V cells) innervate the velum. This complement of cells remains stable for as long as the larval stage persists but metamorphosis causes the rapid loss of the V cells. In the case of SCP-IR neurons, one pair is present prior to metamorphic competency, but as larvae continue to age in the absence of inducing cues, additional pairs are gradually added. Metamorphosis causes an acceleration in SCP-IR neuron addition. This separation of developmental patterns is well adapted for the inherent uncertainty of the timing of metamorphosis in abalone larvae. © 1992 John Wiley & Sons, Inc.

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