| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1996: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1995: ¥1,700,000 (Direct Cost: ¥1,700,000)
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| Research Abstract |
The present study focuses on ultrastructure, acid phosphatase (AcPase) activity of lysosomes and serotonin immunoreactivity in the pineal organs of normal and cold-exposed chickens. Although the pinealocytes of control and cold-exposed chickens possessed lysosome-like dense bodies, they had scarcely any dense-cored vesicles which were typically present in the secretory rudimentary photoreceptor cells of the lacertilian pineal organ. The pinealocytes of the cold-exposed chicken had an invaginated nucleus containing small indistinct nucleoli and smaller number of mitochondria and lysosome-like dense bodies than those of the control chickens. At the ultrastructural level, the AcPase activity was demonstrated in most of these dense bodies in the pinealocytes, which were regarded as lysosomes. Whereas the serotonin immunoreactivity was shown to be localized on a small number of these dense bodies, especially on large ones, and occasionally on the circumference of lipid-like inclusions in the pinealocytes. These results suggested that a part of the dense bodies in the pinealocytes are involved in the indoleamine metabolism of the chicken pineal organ, and they may have functional relationships with the lysosomes. Furthermore, the serotonin immunoreactivity and AcPase activity of the pinelocytes in the cold-exposed chickens were slightly reduced by comparison with those in the control chickens. However, these cytochemical changes owing to cold-exposure were less distinct than those found in seasonal variations of the Japanese lizard pineal (Hirai and Ohshima, 1993). Therefore, the environmental temperature may not have a more drastic effect on the secretory function in the chicken pinealocytes.
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