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The outer segments of photoreceptive pinealocytes in the pineal organ of the funa, Carassius gibelio langsdorfi

A scanning electron microscopic study


The form and size of the outer segments of photoreceptive pinealocytes in the pineal organ of the funa, Carassius gibelio langsdorfi, were observed with the scanning electron microscope. The height of the outer segments measures between 1 and 3 μm and the diameter varies widely from 1.5 to 8 μm. Various forms of outer segments, i.e. a slender type, a dome-like type, a cap-like type and a helical type, were demonstrated. The parallel-oriented filamentous processes of the inner segments have the same length as the outer segments and a diameter of approximately 100 nm; they are projections from the apical border of the inner segment and surround the cone-like outer segments. The processes make a right angle with the lamellar disks. The distance between two processes averages 100 nm. The lamellar disks of the outer segments are oriented at right angles to the modified cilium in the basal part, but the angle often changes in the peripheral part, where the lamellar disks are raised and become parallel to the cilium.

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Correspondence to Prof. Manfred Ueck or Prof. Kenjiro Wake.

Additional information

Supported by a fellowship from the Japan Society for the Promotion of Science and a grant from the Deutsche Forschungsgemeinschaft to M. Ueck

Supported by a grant from the Ministry of Education of Japan to K.Wake

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Ueck, M., Ohnishi, R. & Wake, K. The outer segments of photoreceptive pinealocytes in the pineal organ of the funa, Carassius gibelio langsdorfi . Cell Tissue Res. 186, 259–268 (1978).

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Key words

  • Pineal organ
  • Carassius gibelio langsdorfi (Teleostei)
  • Photoreceptive cell
  • Scanning electron microscopy