A multiple golgi analysis of the periaqueductal gray in the rabbit

Meller, Stephen T.; Dennis, Barbara J.

doi:10.1002/cne.903020106

Cited by 19 publications

(13 citation statements)

References 25 publications

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“…The relative merits of Golgi techniques are well documented (see, e.g., Scheibel and Scheibel, 1978;Buell, 1982;Braak and Braak, 1985;Meller and Dennis, 1990). Nevertheless, modern intracellular injection techniques have focused attention on the limitations of silver-impregnation methods.…”

Section: Methodological Considerationsmentioning

confidence: 99%

Life-span dendritic and spine changes in areas 10 and 18 of human cortex: A quantitative golgi study

Jacobs

Driscoll

Schall³

1997

J. Comp. Neurol.

369

246

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Dendritic neuropil is a sensitive indicator of the aging process and may exhibit regional cortical variations. The present study examined regional differences and age-related changes in the basilar dendrites/spines of supragranular pyramidal cells in human prefrontal (area 10) and secondary occipital (area 18) cortices. Tissue was obtained from the left hemisphere of 26 neurologically normal individuals ranging in age from 14 to 106 years (M(age) = 57 +/- 22 years; 13 males, 13 females). In tissue prepared by a modified rapid Golgi technique, ten neurons were sampled from each cortical region (N = 520) and were evaluated according to the following parameters: total dendritic length, mean segment length, dendritic segment count, dendritic spine number, and dendritic spine density. The effects of age and Brodmann areas were analyzed with a nested multiple analysis of variance design. Despite considerable interindividual variation, several clear findings emerged: 1) Dendritic systems were significantly larger in area 10 than in area 18 across the sampled life span, presumably because of the more integrative function of area 10 neurons. 2) There was a significant age effect, with a substantial decline in dendritic neuropil from the younger (< or =50 years) group to the older (>50 years) group, especially in spine measures, which decreased almost 50%. 3) Dendritic values were relatively stable after 40 years of age, suggesting that dendritic/spine degeneration in older, relatively healthy individuals may not be an inevitable consequence of the aging process. These findings underscore the importance of life-long commitment to a cognitively invigorating environment.

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Section: Methodological Considerationsmentioning

confidence: 99%

Life-span dendritic and spine changes in areas 10 and 18 of human cortex: A quantitative golgi study

Jacobs

Driscoll

Schall³

1997

J. Comp. Neurol.

369

246

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“…The electron microscopic analysis provided new findings regarding the neural relationships of the dendritic spines; in fact, our study provides morphological data that may suggest (along with the literature) that the dendritic spines considerably increase the extension of the synaptic network of the PAG, creating a local device for modulating and integrating afferent inputs, probably in an excitatory way. The comparison between the PAG impregnated neurons of the cat and man showed that in both species the most spiny neurons are multipolar elements, which are the projection neurons of the PAG (Liu and Hamilton, 1980;Meller and Dennis, 1990;Beitz and Shepard, 1985). The differences observed in the characteristics of the dendritic arborization of the neurons in the two species support the idea that an inverse relationship exists between the dendritic tree extension and spine density and complexity and furthermore would seem to indicate that afferent information reaching the projection neurons of the PAG is handled in a different way in man than in the cat.…”

Section: Discussionmentioning

confidence: 99%

“…The study was carried out using Golgi-Cox stained sections, because in the PAG this method gives ''the most satisfactory results both in terms of quality and quantity of cell impregnation,'' spines included (rabbit: Meller and Dennis, 1990). Furthermore, we studied dendritic profiles and spines of PAG neurons in the cat using the electron microscope to clarify their role in the synaptic complexes of this region.…”

Section: Introductionmentioning

confidence: 99%

Dendritic arborization and spines of the neurons of the cat and human periaqueductal gray: A light, confocal laser scanning, and electron microscope study

1998

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Neurons of the periaqueductal gray (PAG) have an extensive dendritic tree which plays an important role in the neuronal circuits supporting the functional activities of this region. The complexity of the local circuits is increased by the occurrence of dendritic spines. We have compared the dendritic and spine organization in the cat with that of man in order to verify whether an inverse relationship exists between dendritic tree extension and spine density and complexity. Sections of cat and human PAG prepared according to the Golgi-Cox method were studied with the conventional light microscope (LM) and the confocal laser scanning microscope (CLSM). The cat PAG was also studied at the electron microscopic level. The light microscopic study provided the morphoquantitative characteristics of the dendritic arborization and spines of the multipolar and fusiform neurons of the human and cat PAG. The CLSM methodology, thanks to the three-dimensional reconstruction of the neurons and the rotation of the reconstructed images, brought into view dendritic branches and spines that could not have been observed at the LM, thereby showing a wider dendritic tree and more numerous spines. The data combined from LM and CLSM demonstrate that in both species most spiny neurons are multipolar and probably projection neurons. In man, the multipolar neurons show a more extensive dendritic tree due to a wider secondary ramification, which would seem to be balanced by more numerous spines in cat. At the electron microscopic level, axo-dendritic synapses are numerous and show symmetrical and asymmetrical junctions in equal proportions; furthermore, the great majority of the spines are in contact with synaptic boutons which contain round vesicles and make predominantly asymmetrical contacts features which indicate excitatory activity. The combined use of different techniques gave a complete picture of the dendritic tree and spines of the neurons of human and cat PAG and showed a wider dendritic surface available for the receipt of the synaptic contacts than had been reported previously. Furthermore, our findings demonstrate that the PAG dendritic spines are important and specific structures in the synaptic complex of the neuropil, suggesting that they might create a local device to modulate and integrate the afferent inputs, probably in an excitatory way. The differences observed in the two species suggest that afferent information might be handled in different ways in human and cat PAG.

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“…Details of the impregnation method are described in a Golgi study of the rabbit PAG (Meller and Dennis, 1990). Sections were cut at 100-150 p m on a vibratome, processed, coverslipped, and viewed using oil immersion at 4 0 0~ to 1,OOOx with an Olympus Vanox microscope.…”

Section: Golgi Methodsmentioning

confidence: 99%

A scanning and transmission electron microscopic analysis of the cerebral aqueduct in the rabbit

Meller

Dennis

1993

Anat. Rec.

Self Cite

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An examination of the surface of the cerebral aqueduct with the scanning electron microscope revealed that the walls of the cerebral aqueduct were so heavily ciliated that most of the ependymal surface was obscured, yet certain specialized supraependymal structures could be discerned lying on (or embedded within) this matt of cilia. These structures were determined by transmission electron microscopy and Golgi analysis to be either macrophages, supraependymal neurons, dendrites from medial periaqueductal gray neurons, or axons of unknown origin. Some axons, which were found to contain vesicles, appeared to make synaptic contacts with ependymal cells. Using the transmission electron microscope, the ependymal lining was found to consist of two different cell types: normal ependymal cells and tanycytes which have a long tapering basal process that was observed to contact blood vessels or, more rarely, seemed to terminate in relation to neuronal elements. While there have been previous reports on the structure of the third and lateral ventricles in other species, there are limited reports in the rabbit. The present report is not only the first description for the rabbit, but it is the first complete scanning and transmission electron microscopic analysis of the cerebral aqueduct in any species.

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A multiple golgi analysis of the periaqueductal gray in the rabbit

Cited by 19 publications

References 25 publications

Life-span dendritic and spine changes in areas 10 and 18 of human cortex: A quantitative golgi study

Life-span dendritic and spine changes in areas 10 and 18 of human cortex: A quantitative golgi study

Dendritic arborization and spines of the neurons of the cat and human periaqueductal gray: A light, confocal laser scanning, and electron microscope study

A scanning and transmission electron microscopic analysis of the cerebral aqueduct in the rabbit

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