Avtor/Urednik		Pregelj, Peter
Naslov		Uravnavanje acetilholinesteraze v podganji mišici soleus v različnih razmerah
Tip		monografija
Kraj izdaje		Ljubljana
Založnik		Medicinska fakulteta
Leto izdaje		2000
Obseg		str. 82
Jezik		slo
Abstrakt		Acetylcholinesterase (AChE) is essential for normal synaptic transmission in the neuromuscular junction. In the rat, the level of AChE mRNA in the typical slow soleus muscle is only about 20- 30a/o of that in the predominantly fast extensor digitorum longus (EDL) muscles. Accordingly, AChE activity in rat fast muscles is much higher than that in the slow soleus. Motor units in the soleus muscle are activated topically with long trains of low-frequency impulses, whereas those in the EDL are excited phasically with rare short high frequency bursts. Tonic low-frequency electrical stimulation of fast muscles makes them slower and decreases their AChE expression. We hypothesized that, accordingly, treatments that make the slow soleus muscle faster would increase AChE mRNA levels in this muscle. We, therefore, examined how four such treatments (changes in muscle load, treatment with thyroid hormones, the phasic pattern of electrical muscle activation, or treatment with cyclosporine, a calcineurin phosphatase inhibitor) influence muscle AChE mRNA levels in the soleus muscle. AChE mRNA levels in muscles were analyzed by Northern blots and evaluated densitometrically. In the soleus muscles, unloaded by hindlimb suspension for 8 days, AChE mRNA levels were not significantly different from the control. A small elevation of AChE mRNA level was indicated only after combination of hindlimb suspension with hindlimb immobilization which maintained the soleus muscle at a medium length. On the other hand, tenotomy of the synergistic gastrocnemius muscle, which overloaded the soleus muscle, significantly increased its AChE mRNA level. AChE mRNA level increased greatly in the soleus muscles of rats, treated for 8 days with the thyroid hormone (T3). The same occured in hyperthyroid rats with a suspended hindlimb. In contrast, there was no change of AChE mRNA level in the EDL muscle of 8 day thyroid hormone treated rats. (Abstract truncated at 2000 characters.)
Deskriptorji		ACETYLCHOLINESTERASE NEUROMUSCULAR JUNCTION ELECTRIC STIMULATION MUSCLE DENERVATION RATS MUSCLE, SKELETAL MUSCLE FIBERS, FAST-TWITCH MUSCLE FIBERS, SLOW-TWITCH AUTORADIOGRAPHY HYPERTHYROIDISM DENSITOMETRY CYCLOSPORINE RNA, RIBOSOMAL