Three-dimensional reconstruction of serotonin-immunoreactive photoreceptors in the pineal organ of the river lamprey, Lampetra japonica.
Serotonin-immunoreactive (5-HT IR) photoreceptors are present in the pineal complex (pineal and parapineal organ) of the river lamprey, Lampetra japonica. They are so-called modified pineal photoreceptors and have been regarded as photoneuroendocrine cells which secrete melatonin. We reconstructed 5-HT IR cells with a computer to demonstrate their three-dimensional structures from optical sections taken by a confocal laser scanning microscope. The 5-HT IR cell possesses a basal process, and it appears that the process does not branch out. These processes contact each other at the basal region of the end vesicle, and a process extends to the soma of the neighboring 5-HT IR cell. These findings were obtained by three-dimensional analysis with a computer, which is a useful technique to demonstrate the interaction between cells. We suggest that the 5-HT IR photoreceptors interact with one another.
Tamotsu
S
S
Department of Physiology, Hamamatsu University School of Medicine, Japan.
Samejima
M
M
Suzuki
N
N
Morita
Y
Y
D000818:Animals; D007091:Image Processing, Computer-Assisted; D007150:Immunohistochemistry; D007798:Lampreys / Q000033:anatomy & histology / Q000502:physiology*; D018613:Microscopy, Confocal; D009415:Nerve Net / Q000166:cytology; D010786:Photoreceptor Cells / Q000166:cytology* / Q000502:physiology; D010870:Pineal Gland / Q000166:cytology / Q000502:physiology*; D012701:Serotonin / Q000502:physiology*
D012701:Serotonin