Accession Number : ADB097611

Title :   Autoregulation of Neuromuscular Transmission by Nerve Terminals.

Descriptive Note : Annual rept. 1 Jul 83-1 Jul 84,

Corporate Author : NEVADA UNIV SCHOOL OF MEDICINE RENO DEPT OF PHARMACOLOGY

Personal Author(s) : Bierkamper, George G.

Report Date : 01 SEP 1984

Pagination or Media Count : 35

Abstract : The objective of this project is to investigate three mechanisms through which acetychloine (ACh) release may be modulated prejunctionally at the motor nerve terminal of skeletal muscle: (1) prejunctional cholinoceptor regulation of ACh release, (2) modulation of ACh release through preconditioning patterns of nerve stimulation, and (3) precursor control of ACh release. Neuromuscular transmission has been assessed in the vascular perfused rat phrenic nerve-diaphragm preparation (VPRH) by measuring the release of ACh directly by radioenzymatic assay or by chemiluminescence assay, and indirectly by intracellular recordings and by force of contradiction (FC) measurements. Additional experiments have been done on rat sciatic nerve in order to examine the axonal transport of nicotinic binding sites. The mouse hemidiahragm preparation has been used to study antidromic activity (backfiring) in the phrenic nerve in the presence of an anticholinesterase agent. The data resulting from the project support the concept that the nerve terminal possesses local mechanism for modulating ACh release. Attempts have been made to understand the normal function of these mechanisms and then to explore their activity under demanding physological conditions, drug exposure, and in the presence of acetylcholinesterase (AChE) inhibitors.

Descriptors :   *NEUROMUSCULAR TRANSMISSION, ACETYLCHOLINE, ASSAYING, BINDERS, CHEMILUMINESCENCE, CHOLINESTERASE INHIBITORS, CONTROL, DRUGS, EXPOSURE(GENERAL), MICE, MODULATION, MOTOR NEURONS, MUSCLES, MUSCULOSKELETAL SYSTEM, NERVE FIBERS, NERVE TRANSMISSION, NERVES, NICOTINIC ACID, PATTERNS, PHRENIC NERVES, PRECURSORS, RATS, SCIATIC NERVE, STIMULATION(PHYSIOLOGY), TERMINALS, RELEASE, SYNAPSE.

Subject Categories : Anatomy and Physiology

Distribution Statement : APPROVED FOR PUBLIC RELEASE