Author/Editor     Črne-Finderle, N; Sketelj, J
Title     Congruity of acetylcholine receptor, acetylcholinesterase, and Dolichos biflorus lectin binding glycoprotein in postsynaptic-like sarcolemmal specializations in noninnervated regenerating rat muscles
Type     članek
Source     J Neurosci Res
Vol. and No.     Letnik 34, št. 1
Publication year     1993
Volume     str. 67-78
Language     eng
Abstract     Noninnervated regenerating muscles are able to form focal postsynaptic-like sarcolemmal specializations either in places of the former motor endplates ("junctional" specializations) or elsewhere along the muscle fibers (extrajunctional specializations). The triple labeling histochemical method was introduced to analyse the congruity of focalization in such specializations of 3 synaptic components: acetylcholinesterase (AChE), acetylcholine receptor (AChR), and a specific synaptic glycoprotein which binds Dolichos biflorus lectin (DBAR). Noninnervated regenerating soleus and extensor digitorum longus (EDL) muscles of the rat were examined and compared with denervated muscles of neonatal and adult rats. All junctional sarcolemmal specializations in noninnervated regenerating muscles accumulated AChE and AChR. Localization of the 2 components was identical within the limits of resolution of the method. DBAR could not be demonstrated in junctional specializations in 17-day-old regenerating muscles. It seems that an agrin-like inducing substance in the former junctional basal lamina invariably triggers the accumulation ofboth AChE and AChR in the underlying sarcolemma of the regenerating muscle fiber. However, accumulation of DBAR would probably require the presence of the motor nerve. In most ofthe extrajunctional sarcolemmal specializations in 8-day-old regenerating soleus and EDL muscles, both AChE and AChR accumulated. However, about 10 percent of AChE accumulations lacked AChR and about 35 per cent of AChR accumulations lacked AChE. Even greather variability was observed in 17 day-old regenerating muscles. The presence of DBAR in the extrajunctional postsynaptic-like sarcolemmal specializations could not be demonstrated. Similar extrajuncti"nal sarcolemmal specializations were observed in denervated postnatal rat muscles. About 70 percent contained both AChE and AChR, and 30 percent contained only AChR, but noen contained DBAR.(trunc.)
Descriptors     ACETYLCHOLINESTERASE
MUSCLES
RECEPTORS, CHOLINERGIC
RECEPTORS, MITOGEN
SARCOLEMMA
MITOGENS
MUSCLE DENERVATION
MUSCLES
RATS
RATS, WISTAR
REGENERATION
SYNAPSES