Trophic regulation of acetylcholinesterase isoenzymes in adult mammalian skeletal muscles.
This work addresses the physiological regulation of skeletal muscle acetylcholinesterase (AChE) isoforms by examining endplate-enriched samples from adult rat gracilis muscles 48 h after: low-intensity treadmill exercise; obturator nerve transection; nerve impulse conduction blockade by tetrodotoxin; acetylcholine (ACh) receptor (AChR) inactivation by alpha-bungarotoxin; and, addition of obturator nerve extracts to muscles in organ culture. Results document the important role(s) of functional AChRs and ACh-AChR interactions in the differential control of individual AChE isoenzymes. A theoretical model based on these and other findings considers that: AChR activation by spontaneously released ACh is the only neural factor required for the maintenance of G1 + G2 AChE; the amount of A12 AChE is determined by the combined effects of ACh and another neurogenic substance; although mechanisms intrinsic to myofibers control normal levels of G4 AChE, enhanced production of this isoform is initiated through increasing the frequency of ACh-AChR interactions.
Fernandez
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HL
Neuroscience Research Laboratory, U.S. Department of Veterans Affairs Medical Center, Kansas City, Missouri 64128.
Hodges-Savola
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CA
D000110:Acetylcholinesterase / Q000378:metabolism*; D000818:Animals; D002038:Bungarotoxins / Q000494:pharmacology; D018680:Cholinergic Antagonists; D007527:Isoenzymes / Q000378:metabolism*; D009043:Motor Activity / Q000502:physiology; D009045:Motor Endplate / Q000201:enzymology; D009132:Muscles / Q000201:enzymology*; D009776:Obturator Nerve / Q000502:physiology / Q000601:surgery; D009924:Organ Culture Techniques; D005082:Physical Exertion; D051381:Rats; D011919:Rats, Inbred Strains; D011950:Receptors, Cholinergic / Q000502:physiology; D009435:Synaptic Transmission; D013779:Tetrodotoxin / Q000494:pharmacology
D002038:Bungarotoxins; D018680:Cholinergic Antagonists; D007527:Isoenzymes; D011950:Receptors, Cholinergic; D013779:Tetrodotoxin; D000110:Acetylcholinesterase