Time-related changes in size of nuclei of pinealocytes in rats

Diehl, Bernhard J. M.

doi:10.1007/bf00210355

Cited by 22 publications

(17 citation statements)

References 32 publications

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“…It was reported that the nuclear volume of peripheral pinealocytes was larger than that of central pinealocytes in the superficial pineal of the rat [Diehl, 1981;Becker and Vollrath, 19831 and, in addition, pinealocyte nuclear volumes in many species including the rat were larger in the superficial pineal than in the deep pineal. However, regional differences in a proximodistal direction have not been described in the superficial pineal itself.…”

Section: Discussionmentioning

confidence: 97%

“…In the superficial pineal of the rat, differences in nuclear size of pinealocytes have previously been described between peripheral and central regions [Diehl, 1981;Becker and Vollrath, 19831. In these studies, however, regional differences in a proximodistal direction have not been considered.…”

Section: Introductionmentioning

confidence: 94%

“…The 24-hr variations in nuclear size of pinealocytes of the rat have repeatedly been investigated [Quay and Renzoni, 1966;Diehl, 1981;Becker and Vollrath, 1983;Diehl et al, 19841. The present study attempted to determine whether or not sizes of pineal glands or pinealocytes of the rat at daytime or nighttime are affected after exposure to a 50 Hz rotating MF, which has recently been found to induce changes in pineal melatonin levels in this animal [Kato et al, in press].…”

Section: Introductionmentioning

confidence: 99%

“…Substantial numbers of studies dealing with effects of magnetic field (MF) exposure on pineal melatonin synthesis have been published [Welker et al, 1983;Olcese et al, 1988;Lerchl et al, 19911. However, morphological data concerning MF effects on the pineal gland are fragmentary [De la Guardia et al, 1988;Stehle et al, 1988;Miline et al, 1988;Martinez Soriano et al, 19921. The 24-hr variations in nuclear size of pinealocytes of the rat have repeatedly been investigated [Quay and Renzoni, 1966;Diehl, 1981;Becker and Vollrath, 1983;Diehl et al, 19841. The present study attempted to determine whether or not sizes of pineal glands or pinealocytes of the rat at daytime or nighttime are affected after exposure to a 50 Hz rotating MF, which has recently been found to induce changes in pineal melatonin levels in this animal [Kato et al, in press].…”

Section: Introductionmentioning

confidence: 99%

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Effect of magnetic field on pineal gland volume and pinealocyte size in the rat

Matsushima

Sakai

Hira

et al. 1993

Journal of Pineal Research

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Light microscopic observations on the superficial pineal gland of Wistar-King rats were made to examine whether or not pineal volume and pinealocyte size, expressed as nuclear density, at daytime or nighttime are affected by long-term exposure to 50 Hz rotating magnetic field (MF) at 5.0 microT. Determinations of pineal volume and pinealocyte size were repeated twice (April and October) during the year. Size of pinealocytes in MF-exposed and sham-exposed rats exhibited, in addition to the difference between peripheral and central regions, regional differences in a proximodistal direction; pinealocytes in the distal and middle-peripheral regions were usually larger than those in the proximal and middle-central regions at daytime or nighttime. In October, distal and proximal pinealocytes showed significant day-night changes in size in sham-exposed rats, but not in MF-exposed animals. The situations in the two groups were almost reversed in April. Significant day-night differences were scarcely found in pinealocyte size in the middle region in the two groups. Throughout the study, pineal volume and pinealocyte size in each region were generally the same between MF-exposed and sham-exposed rats at daytime or nighttime. The results suggest that pinealocytes in the distal and proximal regions, but not those in the middle region, are affected by MF-exposure; day-night differences in sizes of distal and proximal pinealocytes appear in April and disappear in October under the influence of MF. MF may exert an effect on mechanisms controlling day-night rhythms of pinealocyte size in the rat.

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Section: Discussionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Effect of magnetic field on pineal gland volume and pinealocyte size in the rat

Matsushima

Sakai

Hira

et al. 1993

Journal of Pineal Research

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“…In the majority of these studies light microscopic karyometry has been used. Usually, karyometric results show higher values during daytime as compared to those at night (rat: Becker and Vollrath, 1983;Diehl, 1981;Quay and Renzoni, 19661, though no differences over a 24-hour period have been shown (gerbil: Welsh et al, 1979a). In recent electron-microscopic studies of the rat pinealocytes we found larger nuclear cross-sectional areas at night as compared to those during daytime (Karasek et al, 1990).…”

Section: Quantitative Ultrastructurementioning

confidence: 94%

Ultrastructure of the mammalian pinealocyte under natural and experimental conditions: Quantitative aspects

Karasek¹

1992

Microscopy Res & Technique

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This review briefly summarizes data accumulated on the quantitative aspects of the ultrastructure of the mammalian pinealocyte. Quantitative changes have been demonstrated under natural and experimental conditions in pinealocyte cell organelles in various species. Special attention is paid to two cytoplasmic components most frequently studied by means of quantitative electron microscopy, namely, dense-core vesicles and "synaptic" ribbons.

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Quantitative light microscopic study on the heterogeneity in the superficial pineal gland of the rat

1998

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Background: The previous results regarding regional and day-night differences in pinealocyte size in rats are conflicting. The relationships between these differences and the vascularity and sympathetic innervation have scarcely been investigated. Methods: Wistar-King rats, kept under light/dark 12:12, were killed at midday or midnight in October. The nuclear density of pinealocytes in the superficial pineal was measured on the dorsoperipheral, dorsocentral, ventroperipheral, and ventrocentral regions at distal, middle, and proxi-mal levels at daytime and nighttime. The total area of blood vessels per unit area at daytime and nighttime and total length of tyrosine hydroxy-lase (TH)-immunoreactive fibers per unit area at daytime were determined on the same regions at the same levels. Results: Pinealocyte size was larger toward the distal levels and in the periphery than in the center at any level. The area of blood vessels and length of TH fibers were also larger toward the distal levels; the former in the ventral region and the latter in the dorsal and ventral regions were larger in the periphery than in the center. Ventral pinealocytes, but not dorsal ones, showed day-night changes in size. Prominent day-night rhythms in area of blood vessels occurred in the ventral region, where TH fibers were more abundant than in the dorsal region. Conclusions: Pinealocyte size shows the distal to proximal and peripheral to central gradients, which may be related to the differential distribution of blood vessels and sympathetic fibers. Since pinealocytes and blood vessels, showing prominent day-night changes in size, are localized in the more richly innervated regions, sympathetic fibers may play an important role in controlling these rhythms. Anat. Rec. 250:80-94, 1998. 1998 Wiley-Liss, Inc. The unequivocal morphological evidence for a circa-dian rhythmicity in the pineal gland of mammals was first described by Quay and Renzoni (1966), who demonstrated that the nuclear and nucleolar sizes of the pinealocytes of the rat show similar rhythms, with maximums at midday and low values during the night-time, and that the nuclear and nucleolar sizes are similar between peripheral (cortical) and central (med-ullary) regions. Thereafter, determinations of the size of the pinealocytes in the peripheral and central regions at various time points during a 24-h period in rats have been repeated by many investigators (Diehl, 1981; Becker and Vollrath, 1983; Diehl et al., 1984; Lew et al., 1984; Karasek et al., 1990). However, the original findings by Quay and Renzoni (1966) have not always been reproducible. It is therefore an open question whether the size of pinealocytes differs in different regions and whether 24-h rhythms in the size of pinealocytes exist in different regions in the pineal gland of the rat. Our previous studies revealed that the size of pinealo-cytes of mice (Matsushima et al., 1989) and Chinese hamsters (Matsushima et al., 1983; Sakai et al., 1986; Hira et al., 1989) exhibited a 24-h rhythm similar to that described ...

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Time-related changes in size of nuclei of pinealocytes in rats

Cited by 22 publications

References 32 publications

Effect of magnetic field on pineal gland volume and pinealocyte size in the rat

Effect of magnetic field on pineal gland volume and pinealocyte size in the rat

Ultrastructure of the mammalian pinealocyte under natural and experimental conditions: Quantitative aspects

Quantitative light microscopic study on the heterogeneity in the superficial pineal gland of the rat

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