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Vol. 38 No. 4, 1999
A Comparative Study of Neuropeptide Y-Immunoreactivity in the
Retina of Dolphin and Several Other Mammalian Species
Shur-Tzu
Chen1, Ching-Liang Shen1, Jiang-Ping Wang2,*
and Lien-Siang Chou3
1Department
of Anatomy, National Cheng Kung University Medical College, Tainan,
Taiwan 701
2Department of Biology, National Cheng Kung
University, Tainan, Taiwan 701
3Department of Zoology, National Taiwan University,
Taipei, Taiwan 106
Shur-Tzu
Chen, Ching-Liang Shen, Jiang-Ping Wang and Lien-Siang Chou (1999)
The immunoreactivity of an antibody to neuropeptide Y (NPY) in the
retina of striped (Stenella
coeruleoalba) and Fraser (Lagenodelphis
hosei) dolphins and several other species was studied and
compared. In dolphin retina, moderate to intense immunostaining was
observed primarily in the giant retinal ganglion cells and their
dendrite-like processes, while ganglion cells with smaller somata were
only weakly immunoreactive. In contrast, NPY immunoreactive cell bodies
are mainly located in cells with small somata in the ganglion cell
layer and cells resembling amacrine cells in the inner nuclear layer in
rat retina. Positive immunostaining was also observed in the inner and
outer plexiform layers of rat retina, a feature that was not found in
dolphin retina. Interestingly, the overall pattern of NPY expression in
the retina of dolphin is similar to that in dog but not in rat, or
other mammalian species described previously. One possible explanation
is that dolphin and dog are more active by day as compared with rat and
cat which are considered to be nocturnal. The variable pattern of
distribution of NPY observed in different species suggests that NPY
plays a unique functional role, for instance, in the demand for higher
levels of blood supply for visual connections through the influence of
NPY, in the retinal system in a species-dependent manner probably
related to animals’ visual behaviors and environments.
Key words: NPY,
Retina, Cetacean, Immunohistochemistry.
*Correspondence: Fax: 886-6-2093007. E-mail:
wangcp@mail.ncku.edu.tw
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