Metabolic Stabilization of Acetylcholine Receptors in Vertebrate Neuromuscular Junction by Muscle Activity

• Published in: The Journal of cell biology 1990-08, Vol.111 (2), p.655-661
• Main Authors: Rotzler, S., Brenner, H. R.
• Format: Article
• Language: English
• Subjects: 550501 - Metabolism- Tracer Techniques; ACETYLCHOLINE; AMINES; AMMONIUM COMPOUNDS; ANIMALS; AUTONOMIC NERVOUS SYSTEM AGENTS; Autoradiography; BASIC BIOLOGICAL SCIENCES; BETA DECAY RADIOISOTOPES; BIOCHEMISTRY; BIOLOGICAL ACCUMULATION; Biological and medical sciences; Bungarotoxins - metabolism; Cell receptors; Cell structures and functions; CHEMISTRY; Cholinergic receptors; DAYS LIVING RADIOISOTOPES; Denervation; DRUGS; ELECTRON CAPTURE RADIOISOTOPES; End plates; ESTERS; Fundamental and applied biological sciences. Psychology; Half lives; Innervation; INTERMEDIATE MASS NUCLEI; IODINE 125; IODINE ISOTOPES; Iodine Radioisotopes; ISOTOPE APPLICATIONS; ISOTOPES; Kinetics; Male; MAMMALS; MEMBRANE PROTEINS; METABOLISM; Molecular and cellular biology; Monoamines receptors (catecholamine, serotonine, histamine, acetylcholine); Motor Endplate - physiology; Muscle Denervation; MUSCLES; Muscles - innervation; Muscles - physiology; NERVES; NERVOUS SYSTEM; Neuromuscular Junction - physiology; NEUROREGULATORS; NUCLEI; ODD-EVEN NUCLEI; ORGANIC COMPOUNDS; PARASYMPATHOMIMETICS; PROTEINS; QUATERNARY COMPOUNDS; RADIOISOTOPES; RATS; Rats, Inbred Strains; RECEPTORS; Receptors, Cholinergic - metabolism; RODENTS; Space life sciences; STABILITY; Synapses; TRACER TECHNIQUES; VERTEBRATES
• ISSN: 0021-9525; 1540-8140
• DOI: 10.1083/jcb.111.2.655

The effects of muscle activity on the growth of synaptic acetylcholine receptor (AChR) accumulations and on the metabolic AChR stability were investigated in rat skeletal muscle. Ectopic end plates induced surgically in adult soleus muscle were denervated early during development when junctional AChR number and stability were still low and, subsequently, muscles were either left inactive or they were kept active by chronic exogenous stimulation. AChR numbers per ectopic AChR cluster and AChR stabilities were estimated from the radioactivity and its decay with time, respectively, of end plate sites whose AChRs had been labeled with 126 I-α -bungarotoxin (α-butx). The results show that the metabolic stability of the AChRs in ectopic clusters is reversibly increased by muscle activity even when innervation is eliminated very early in development. 1 d of stimulation is sufficient to stabilize the AChRs in ectopic AChR clusters. Muscle stimulation also produced an increase in the number of AChRs at early denervated end plates. Activity-induced cluster growth occurs mainly by an increase in area rather than in AChR density, and for at least 10 d after denervation is comparable to that in normally developing ectopic end plates. The possible involvement of AChR stabilization in end plate growth is discussed.