Projects / Programmes
Struktura in funkcija skeletne mišice v fizioloških, eksperimentalnih in patoloških pogojih (Slovene)
| Code |
Science |
Field |
Subfield |
| 3.03.00 |
Medical sciences |
Neurobiology |
|
| Code |
Science |
Field |
| B210 |
Biomedical sciences |
Histology, cytochemistry, histochemistry, tissue culture |
| B580 |
Biomedical sciences |
Skeleton, muscle system, rheumatology locomotion |
skeletal muscle, myosin heavy chain isoforms, regeneration, immunohistochemistry, electrophoresis, human , rat, mouse, dog, electrical stimulation, motor units, fibre types, hybridisation in situ
Researchers (15)
Organisations (2)
Abstract
In human muscles four groups of fibre types have been defined in regard to MHC-isoform expression, transcripts for the protein and at the enzyme level. Inconsistencies between results obtained at different levels point to muscle fibre type transformations.First studies analysing extensors and flexors of human upper and lower extremity show a good correlation between biomehanical and histochemical characteristics of the same muscles .
Expression of myosin heavy chain isoforms has been studied in six month regenerated rat soleus and extensor digitorum longus muscles after muscle excision and transplantation to the extensor digitorum longus muscle bed. Our experimental model compared to other models, described in literature provokes the biggest shift of the MHC isoform profile toward faster MHC-isoforms.
Low frequency electrical stimulation of regenerated rat extensor digitorum longus muscle transforms the fast muscle into a muscle with evidently increased proportion of MHC-2a expressing fibres and with up to 20 percents of MHC-1 expressing fibres. In control stimulated EDL muscle the share of MHC-1 expressing fibres did not change.
A basis for 3-D reconstruction of the capillary network in rat skeletal muscle has been established and relevant stereological methods for quantification developed.
To find the impulse pattern that mimics the physiological one which provokes muscle contraction “in vivo” we determined the fibre type of glycogen depleted fibres in two types of electrical stimulation, with alternating rectangular impulses and with trapezoidal impulses. Both impulse patterns stimulated motor units, consisting of 2A fibres in dog.
Levator auris longus muscle of mouse has been used as a model to study sprouting of motor nerve terminals after botulinum A toxin injection. We tested the hypothesis that the two types of sprouting are caused by intrinsic characteristics of slow and fast muscle fibres. The hypothesis has been rejected by immunohistochemical analysis that proved the LAL muscle as a homogeneous fast twitch muscle.
