Age‐related changes in pineal “synaptic” ribbon populations in rats exposed to continuous light or darkness

King, Thomas S.; Dougherty, William J.

doi:10.1002/aja.1001630206

Cited by 36 publications

(21 citation statements)

References 19 publications

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“…Whereas the three-dimensional structure of SR and SP is well known in guinea-pigs, that of IMF is not (Vollrath et al, 1983). Perhaps they are platelike with varying forms due to sectioning (King and Dougherty, 1982a). To clarify this point, analysis of serial sections is required.…”

Section: Resultsmentioning

confidence: 99%

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Postnatal development of “Synaptic” ribbons and spherules in the guinea pig pineal gland

1985

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Previous studies have shown that the functionally enigmatic pineal "synaptic" ribbons are structurally a heterogeneous group of organelles consisting of rodlike ribbons sensu stricto, spherules, and intermediate forms. As ribbons and spherules react differently under various experimental conditions, these organelles were studied qualitatively and quantitatively during the postnatal period in guinea pigs. It was found that the pinealocytes were highly differentiated at birth and contained all three forms of "synaptic" structures. Ribbons and intermediate forms were more abundant than spherules and exhibited a striking increase in number on postnatal days 1 and 2; this increase was followed by a distinct trough and by a second peak at days 12 and 13, after which their numbers declined to reach adult levels by day 20. The spherules were small in number at birth and did not show the large immediate postnatal increase observed for the ribbons and intermediate forms. Instead there was a steady numerical increase up to day 12 (absolute number) or day 15 (relative numbers), followed by a decrease to adult level by day 20. Whereas during the early postnatal period (days 1 to 3) the majority of pinealocytes were characterized by ribbons and intermediate forms, with increasing age spherule-bearing pinealocytes increased in number. As ribbons and spherules were usually not found in the same pinealocyte, the present findings are interpreted to mean that ribbons and spherules characterize different types of pinealocytes showing an inverse numerical development postnatally. Developmentally intermediate forms behave like ribbons.

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Section: Resultsmentioning

confidence: 99%

“…In addition to SR and SP, intermediate forms (IMF) are present, appearing as irregularly thickened bars or irregular electron densities surrounded by electron-lucent vesicles (King and Dougherty, 1982a;Karsek and Vollrath, 1982;Vollrath et al, 1983). These IMF appear to be functionally more closely related to SR than to SP.…”

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confidence: 99%

Postnatal development of “Synaptic” ribbons and spherules in the guinea pig pineal gland

1985

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“…Propranolol, a p-adrenergic blocker, prevented the normal nocturnal increase in SR numbers in guinea pigs (Vollrath and Howe, 1976), but had no effect on SR in rats (Seidel et al, 1990b). Propanolol did, however, reverse the increased frequency of SR in rats after exposure to continual darkness (King and Dougherty, 1982a).…”

Section: Role In Endocytosis and Receptor Mechanismsmentioning

confidence: 64%

“…The plane of section is depicted by a n arrow in a. The section b was Karasek and Vollrath, 1982Kurumado and Mori, 1977Kurumado and Mori, 1980Maitra et al, 1986McNulty et al, 1985McNulty et al, 1987McNulty et al, 1989Reuss et al, 1989Vollrath et al, 1985Vollrath and Maitra, 1986Vollrath and Welker, 1984Net0 et al, 1990Saidapur et al, 1991bKing and Dougherty, 1980King and Dougherty, 1982aKing and Dougherty, 1982b McNulty, this study Saidapur et al, 1991bKosaras et al, 1983aKosaras et al, 1983bSaidapur et al, 1991bSaidapur et al, 1991bSaidapur et al, 1991bRiemann et al, 1990Seidel et al, 1990aKarasek et al, 198313 Karasek et al, 1983cKarasek et al, 1982aHewing, 1981 Karasek et al, 1983bKarasek et al, 1983aVollrath, 1973Vollrath and Huss, 1973Vollrath and Howe, 1976Vollrath, 1986Vollrath et al, 1983Khaledpour and Vollrath, 1987 Fechner, 1986Karasek et al, 1982cKarasek et al, 1983bHewing, 1979Hewing, 1980Vollrath and Maitra, 1986Diaz et al, 1990Heinzeller, 1985 tories may...…”

Section: Ribbon Fieldsmentioning

confidence: 65%

Pinealocyte synaptic ribbons and neuroendocrine function

McNulty

Fox

1992

Microscopy Res & Technique

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A comparative study of pinealocyte synaptic ribbons (SR) revealed two predominant populations exhibiting either a rod/ribbon shape (SRr) or a spherical/punctate shape (SRsp). Species-specific differences were found in the abundance of SR, the ratio of SRr/SRsp, and the occurrence of SR in ribbon fields. The close topographical relationship of SR to the plasma membrane and the numerical changes that occurred with changes in metabolism of the pinealocytes suggest that SR have important vesicle-mediated interactions with the cell membrane. Experiments designed to clarify the relationship between SR and pineal neuroendocrine function revealed a positive correlation between SR numbers and indole intermediates during pineal development in the rat, and increased SR frequency after denervation of the rat pineal gland or administration of the beta-adrenergic agonist, isoproterenol. These data are consistent with the hypothesis that SR function is linked to receptor mechanisms regulating indoleamine production in the pineal gland.

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“…1974;Matsushima and Reiter 1977;King and Dougherty 1982). Thus, it has been maintained that adrenergic terminals containing dense-cored vesicles terminate only in the interstitial spaces in close vicinity to pinealocytes (Romijn 1973).…”

Section: Discussionmentioning

confidence: 99%

Synaptic junctions between sympathetic axon terminals and pinealocytes in the monkey Macaca fascicularis

1990

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The distribution of axon terminals in the pineal gland of monkeys was studied by electron microscopy. Numerous terminals bearing small pleomorphic agranular and dense-cored vesicles were localized in the perivascular space and among the pinealocytes in the parenchyma in normal monkeys. Following bilateral superior cervical ganglionectomy, they underwent degenerative changes, including the accumulation of glycogen masses, appearance of dense residual bodies and the displacement of synaptic vesicles. Some of these degenerating terminals showed synaptic contacts with the cell bodies of pinealocytes. At the synaptic junction the postsynaptic membrane was thickened asymmetrically. Examples of synaptic contacts were most frequently observed in 5 and 7 days postoperative animals. In the longer surviving (30 days) monkey, most of the axon terminals showed round agranular vesicles, and they were mainly presynaptic to the intrapineal ganglion cells with some of the pinealocytes. They remained structurally unchanged following the resection of both the superior cervical ganglia. A few axon terminals containing small dense-cored vesicles appeared to have survived the initial insult, but some of their vesicles appeared swollen 30 days after the operation. It is concluded from this study that some of the pinealocytes are under the influence by the postganglionic neurons in the superior cervical ganglia through direct synaptic contacts. The intrapineal ganglion cells are postsynaptic to fibres originating exclusively from the central nervous system. Some of these fibres, however, may be presynaptic directly to pinealocytes.

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Age‐related changes in pineal “synaptic” ribbon populations in rats exposed to continuous light or darkness

Cited by 36 publications

References 19 publications

Postnatal development of “Synaptic” ribbons and spherules in the guinea pig pineal gland

Postnatal development of “Synaptic” ribbons and spherules in the guinea pig pineal gland

Pinealocyte synaptic ribbons and neuroendocrine function

Synaptic junctions between sympathetic axon terminals and pinealocytes in the monkey Macaca fascicularis

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