Accession Number : ADB093653

Title :   Cellular Actions and Interactions of Anticholinesterases and Their Antidotes in Mammalian Autonomic Neurons.

Descriptive Note : Annual summary rept. 15 Apr 83-14 Apr 84,

Corporate Author : STRITCH SCHOOL OF MEDICINE MAYWOOD IL

Personal Author(s) : Dun, N. J.

Report Date : 04 JUN 1984

Pagination or Media Count : 30

Abstract : The effects of non-organophosphorus anticholinesterase (Anti-ChE) agents neostigmine and physostigmine in neurons of the isolated rabbit superior cervical ganglia and on ganglionic transmission were investigated by means of intracellular recording techniques. At concentrations of 10 micrometers or less, these agents consistently and reversibly increased the amplitude and duration of the fast excitatory postsynaptic potential (F-epsp) evoked by single-nerve stimulation and of the nicotinic acetylcholine (ACh) depolarization by electrophoretically applied ACh. On the other hand, anti-ChE's at concentrations of 50 micrometers or higher reversibly depressed the f-epsp as well as the nicotinic ACh depolarization. With respect to the muscarinic transmission which was evoked by repetition nerve stimulation (10-20 Hz, 1-2 sec), anti-ChE's at lower concentration preferentially increased the slow inhibitory postsynaptic potential (s-ipsp) over the slow excitatory postsynaptic potential (s-epsp). At higher concentrations, anti-ChE's produced a biphasic effect consisting of an initial depression followed by an increase of s-epsp. Vasoactive intestinal polypeptide (VIP) was found to enhance muscarinic transmission, possibly by increasing against bindings to muscarinic receptors, and catecholamines potentiated muscarinic and peptidergic transmission by a cyclic AMP-dependent mechanism. Serotonin appeared to be the transmitter mediating a slow excitatory potential, the function of which is to enhance nicotinic transmission.

Descriptors :   *ANTIDOTES, *CHOLINESTERASE INHIBITORS, *AUTONOMIC NERVOUS SYSTEM, *NERVE CELLS, CATECHOLAMINES, INTERACTIONS, MAMMALS, ACETYLCHOLINE, NICOTINIC ACID, MUSCARINE, RECEPTION, GANGLIA, CELLS(BIOLOGY), RECORDING SYSTEMS, NICOTINIC ACID, TRANSMITTANCE, PHYSOSTIGMINE, SEROTONIN, REPETITION RATE, STIMULATION(PHYSIOLOGY), ACETYLCHOLINESTERASE, NERVE TRANSMISSION.

Subject Categories : Pharmacology

Distribution Statement : APPROVED FOR PUBLIC RELEASE