The ultrastructural anatomy of the nuclear envelope in the masseter muscle indicates its role in the metabolism of the intracellular Ca++
| Autor: | Dănuţ Dincă, A. C. Ilie, Adelina Maria Jianu, Mugurel Constantin Rusu, V.S. Mănoiu, Mihnea Ioan Nicolescu |
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| Rok vydání: | 2019 |
| Předmět: |
Male
Sarcomeres 0301 basic medicine Nuclear Envelope Muscle Fibers Skeletal chemistry.chemical_element Calcium Mitochondrion Masseter muscle 03 medical and health sciences Sarcolemma Microscopy Electron Transmission Myofibrils medicine Animals Cell Nucleus Voltage-dependent calcium channel Masseter Muscle Ryanodine receptor Endoplasmic reticulum Skeletal muscle General Medicine Anatomy Mitochondria Cytosol 030104 developmental biology medicine.anatomical_structure chemistry Microvessels Models Animal Rabbits 030101 anatomy & morphology Developmental Biology |
| Zdroj: | Annals of Anatomy - Anatomischer Anzeiger. 224:117-123 |
| ISSN: | 0940-9602 |
| DOI: | 10.1016/j.aanat.2019.05.006 |
| Popis: | Specific ultrastructural anatomy of masticatory muscles is commonly referred to a general pattern assigned to striated muscles. Junctional feet consisting of calcium channels of the sarcoplasmic reticulum (i.e. the ryanodine receptors, RyRs) physically connected to the calcium channels of the t-tubules build triads within striated muscles. Functional RyRs were demonstrated in the nuclear envelopes of pancreas and of a skeletal muscle derived cell line, but not in muscle in situ. It was hypothesized that ryanodine receptors (RyRs) could also exist in the nuclear envelope in the masseter muscle, thus aiming at studying this by transmission electron microscopy. There were identified paired and consistent subsarcolemmal clusters of mitochondria, appearing as outpockets of the muscle fibers, usually flanking an endomysial microvessel. It was observed on grazing longitudinal cuts that the I-band-limited mitochondria were not strictly located in a single intermyofibrillar space but continued transversally over the I-band to the next intermyofibrillar space. It appeared that the I-band-limited transverse mitochondria participate with the column-forming mitochondria in building a rather incomplete mitochondrial reticulum of the masseter muscle. Subsarcolemmal nuclei presented nuclear envelope-associated RyRs. Moreover, t-tubules were contacting the nuclear envelope and they were seemingly filled from the perinuclear space. This could suggest that nucleoplasmic calcium could contribute to balance the cytosolic concentration via pre-built anatomical routes: (i) indirectly, via the RyRs of the nuclear envelope and (ii) directly via the communication of t-tubules and sarcoplasmic reticulum through the perinuclear space. |
| Databáze: | OpenAIRE |
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