The castration atrophy of the dorsal bulbocavernosus muscle of rat: An electron microscopic study

Gori, Zina; Pellegrino, C; Pollera, Maria

doi:10.1016/0014-4800(67)90054-8

Cited by 34 publications

(11 citation statements)

References 28 publications

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“…In tenmonth-old rats neutered before puberty, LA wet weight and myofiber cross-sectional area more than doubled in 15 days after an injection of 1.0 mg of depot testosterone and no alteration of the structural pattern in the myofibers was observed (Venable, 1966). Other than its more rapid pace of evolution, denervation atrophy, according to Gori et al (1967), was not substantially different from castration atrophy. Nuclear population dynamics, however, are dissimilar in both models (Nnodim, 1999), with androgens playing a significant permissive role.…”

Section: Discussionmentioning

confidence: 86%

“…The above changes indicate the very wide morphological range across which the LA responds to manipulations of its trophic inputs. These changes are mirrored in studies that have considered alterations in whole-muscle wet weight (Venable, 1966;Gori et al, 1967;Bass et al, 1969). Gori et al (1967) found that after castration, muscle weight was nearly halved (55% of normal) in 15 days, decreasing to 39.5% in 1 month and 15.6% in 8 months.…”

Section: Discussionmentioning

confidence: 86%

“…These changes are mirrored in studies that have considered alterations in whole-muscle wet weight (Venable, 1966;Gori et al, 1967;Bass et al, 1969). Gori et al (1967) found that after castration, muscle weight was nearly halved (55% of normal) in 15 days, decreasing to 39.5% in 1 month and 15.6% in 8 months. At the ultrastructural level, the overall integrity of the contractile apparatus was qualitatively preserved.…”

Section: Discussionmentioning

confidence: 86%

“…This linear reduction would seem to be effected through the partial deletion of myofiber substance. Gori et al (1967) described deep invaginations of the sarcolemma and basal lamina into the sarcoplasm as well as completely detached fragments of myofiber in the interstitium of LA during atrophy. They also noted that these "blocks of sarcoplasm" were subsequently phagocytosed by macrophages.…”

Section: Discussionmentioning

confidence: 99%

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Testosterone mediates satellite cell activation in denervated rat levator ani muscle

Nnodim

2001

Anat. Rec.

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Denervation stimulates quiescent satellite cells in skeletal muscle to reenter the cell cycle. In the androgen-sensitive rat levator ani muscle (LA), this mitotic response to loss of neural input fails to occur in castrated animals. To elucidate the role of androgens in denervation-induced satellite cell proliferation, the denervated LA of castrated rats (Group A) was compared with that of animals infixed with testosterone implants after castration (Group B). Mean myofiber cross-sectional areas (Group A: 362.95 m 2 Ϯ 27.74; Group B: 403.13 m 2 Ϯ 53.87) and linear nuclear densities (Group A: 74.07 mm Ϫ1 Ϯ 17.58; Group B: 104.13 mm Ϫ1 Ϯ 4.06) were similar (P Ͼ 0.05) in both groups. The androgen-deprived myofibers of Group A, however, had a significantly lower nuclear content (271.0 Ϯ 74.91 vs. 1,285.80 Ϯ 81.74 in Group B; P Ͻ 0.05) on account of their considerably shorter mean length (3.44 mm Ϯ 0.29 vs. 12.31 mm Ϯ 0.92 in Group B; P Ͻ 0.05). The proportional representation of satellite cells in hormone-replaced, denervated muscle was more than twice that in the untreated group (Group B: 5.15 Ϯ 0.83% vs. Group A: 2.28 Ϯ 0.23%; P Ͻ 0.05). In absolute terms, the satellite cell number in Group B was approximately an order of magnitude greater than in Group A (408.4 ϫ 10 3 vs. 38.08 ϫ 10 3 ). The results confirm the absence of testosterone as the factor responsible for the inability of satellite cells in the LA of castrated rats to respond mitotically to the withdrawal of neural input after denervation.

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Section: Discussionmentioning

confidence: 86%

Section: Discussionmentioning

confidence: 86%

Section: Discussionmentioning

confidence: 86%

Section: Discussionmentioning

confidence: 99%

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Testosterone mediates satellite cell activation in denervated rat levator ani muscle

Nnodim

2001

Anat. Rec.

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“…muscle cells. These same authors have claimed to have seen this T-system network in one case of atrophy of the bulbocavernosus muscle following castration (Gori et al, 1967). It is interesting to note some factors existing both in cultured and in atrophied muscles.…”

Section: Discussionmentioning

confidence: 87%

Formation of Elaborate Networks of T-System Tubules in Cultured Skeletal Muscle With Special Reference to the T-System Formation

Ishikawa

1968

The Journal of Cell Biology

238

109

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Muscle cells, cultured for 1-28 days from I 1-day chick embryo breast muscles, often show elaborate, three-dimensional networks of a membranous system. The network consists of tubular units which are quite regularly arranged. The tubular units composing the network are accessible to ferritin particles suspended in the culture medium; this suggests continuity with the extracellular fluid. These networks can be regarded as a special morphological elaboration of the T-system tubules. Such network formations can be seen much more often in well-developed myotubes. The networks usually exhibit a hexagonal pattern, which is formed of tubular units of a constant diameter. However, some early myotubes contain tetragonal networks, which are composed of spherical pockets with channels of lesser diameter connecting the pockets. Networks are also observed which probably represent a transitional form between these two patterns. Myotubes show many inpocketings of the sarcolemma similar to what are commonly referred to as caveolae or micropinocytotic vesicles. The similarity in configuration and dimension of the tubular units of the network to the caveolae leads to the plausible suggestion that repeated caveola-formation from the sarcolemma or T-system tubule may result in formation of these networks. In this connection, a possible mechanism of the T-system tubule formation is discussed.

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Quantitative study of the effects of denervation and castration on the levator ani muscle of the rat

Nnodim

1999

Anat. Rec.

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The levator ani muscle (LA) of the rat is highly androgen-sensitive and, like all skeletal muscles, deteriorates structurally and functionally when denervated. In order to elucidate the interplay of neural and endocrine influences, the separate and combined effects of denervation and castration on myofiber cross-sectional area and nuclear populations were quantitatively studied. In one group of 4-month-old male rats (A), the LA was denervated. Another group (B) was surgically castrated and a third group (C) was both denervated and castrated. The control rats (D) remained both gonad-and nerve-intact. After two months, the LA was obtained for myofiber and nuclear enumeration, cross-sectional area and satellite cell frequency determination. In the denervated muscle of gonad-intact rats (Group A), myofiber cross-sectional area was markedly diminished (265.84 11.38µm 2 ; compared with controls [Group D]: 1519.98 79.41µm 2 ; P 0.05). Satellite cell nuclei, as a percentage of total sublaminar nuclei (i.e., satellite cell ratio), increased significantly (4.26%, from a control value of 1.91%). Castration alone (Group B) resulted in pronounced myofiber atrophy (mean cross-sectional area: 754.03 89.63µm 2) but had no significant effect on satellite cell ratio (2.36%). The combination of castration and denervation (Group C) elicited the same degree of myofiber atrophy as denervation alone (Group A) but had no significant impact on satellite cell ratio. Instead, the nuclear count per myofiber declined to about a third of the control level (300.5 38.49 compared with 861.7 24.8; P 0.05). The results indicate that the atrophic effects of denervation and castration on the LA are non-synergistic and mechanistically similar. They also show that the inability of satellite cells to respond mitotically to the withdrawal of neural input under disandrogenized conditions is a factor in the myonuclear depletion of the denervated muscle of castrated rats. Anat

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The castration atrophy of the dorsal bulbocavernosus muscle of rat: An electron microscopic study

Cited by 34 publications

References 28 publications

Testosterone mediates satellite cell activation in denervated rat levator ani muscle

Testosterone mediates satellite cell activation in denervated rat levator ani muscle

Formation of Elaborate Networks of T-System Tubules in Cultured Skeletal Muscle With Special Reference to the T-System Formation

Quantitative study of the effects of denervation and castration on the levator ani muscle of the rat

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