Avtor/Urednik		Sketelj, Janez; Črne-Finderle, Neva; Štrukelj, Borut; Trontelj, Jože V; Pette, Dirk
Naslov		Acetylcholinesterase mRNA level and synaptic activity in rat muscles depend on nerve-induced pattern of muscle activation
Tip		članek
Vir		J Neurosci
Vol. in št.		Letnik 18, št. 6
Leto izdaje		1998
Obseg		str. 1944-52
Jezik		eng
Abstrakt		Acetylcholinesterase (AChE) mRNA levels are severalfold higher in fast rat muscles compared with slow. We hypothesized that AChE mRNA levels and AChE activity in the neuromuscular junction depend on a specific nerve-induced pattern of motor unit activation. Chronic low-frequency stimulation, mimicking the activation pattern inslow muscles, was applied to fast muscles in rats. molecular forms of AChE were analyzed by velocity sedimentation, and AChE mRNA levels were analyzed by Northern blots. AChE mRNA levels in stimulated fast musles dropped to 10-20% of control after 1 week and became comparable to those inslow soleus muscles. The activity of the junctional A12 AChE form in 35 od stimulated fast muscles decreased to 56% of control value, reaching that in the soleus muscle. Therefore, synaptic AChE itself depends on the muscle activation patern. Complete inactivity after denervation also decreased the AChE mRNA level in fast muscles to <10% in 48 hr. In contrast, profuse fibrillations observed in noninnervated immature regenerating muscles maintain AChE mRNA levels at 80% of that in the innervated fast muscles.If protein synthesis was inhibited by cycloheximade, AChE mRNA levels in 3-d-old regenerating muscle, still containing myoblasts, increased approximately twofold. No significant increase after cycloheximide application was observed either in denervated mature fast muscles or in normal slow muscles. Low AChE mRNA levels observed in those muscles are probably not caused by decreased stability of AChE mRNA as demonstrated in myoblasts.
Deskriptorji		ACETYLCHOLINESTERASE MUSCLES RNA, MESSENGER SYNAPSES RATS, WISTAR MUSCLE DENERVATION CYCLOHEXIMIDE PROTEIN SYNTHESIS INHIBITORS REGENERATION