Astrocytes are essential for lipid neuronal metabolism in long-distance
uninterrupted migratory flights, when glucose is not available as the main source
of energy. We previously demonstrated in Calidris pusilla that after uninterrupted
5 days transatlantic flight, astrocytes shrink and reduce its number in the
hippocampal formation. Here we shifted our attention to the wintering period and
tested the hypothesis that as the wintering progresses, hippocampal astrocytes
morphological changes following Atlantic crossing, would be recovered. To that
end we used Arenaria interpres, which also crosses the Atlantic Ocean and
reaches the mangroves of the Amazon River estuary for wintering. Birds were
captured in September/October (closer to the arrival in the coast of Bragança -
Pará, Brazil for wintering) and in April/May (closer to the departure towards the
breeding sites) and had their brains processed for selective GFAP-astrocyte
immunolabeling. Three-dimensional reconstructions of the immunostained
astrocytes were performed and morphological classification was done based on
hierarchical cluster and discriminant analysis of multimodal morphometric
features. We found two morphological phenotypes of astrocytes exhibiting
distinct morphological complexities after the long-distance non-stop transatlantic
flight. Although to a different extent, both morphotypes increased their
complexities as wintering period progresses towards the pre-migration window.
Taken together, our findings demonstrate that the long-distance non-stop flight
and wintering period differentially affected the two astrocytes morphotypes,
suggesting distinct physiological roles for these cells. We suggest that
morphological recovering during the wintering period, may be part of the adaptive
changes of the local hippocampal circuits of A. interpres in preparation for the
long journey back to their breeding sites in the north hemisphere.
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