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The action of acetylcholine and cholinesterase inhibitors on single axons of the lobster

1968; Elsevier BV; Volume: 17; Issue: 9 Linguagem: Inglês

10.1016/0006-2952(68)90099-3

1873-2968

Wolf-Dietrich Dettbarn, Eva Bartels,

Molecular Junctions and Nanostructures

Acetylcholine (ACh), physostigmine and related substances have been tested for their effects on the electrical activity of single giant axons of the circumesophageal connectives of the lobster. Acetylcholine and physostigmine in concentrations of 5 × 10−3 to 1 × 10−2M depolarize the membrane. The simultaneously recorded action potential is prolonged, and with progressive depolarization reversible block of conduction occurs. Both compounds cause initially spontaneous or repetitive firing. Neostigmine, 3-hydroxyphenyltrimethylammonium and edrophonium prevent the effect of ACh without having an effect of their own on membrane or action potential. Choline, cholinethiol and phenyltrimethylammonium do not antagonize the action of ACh, nor do they change the electrical parameters of the axon. Curare depolarizes the membrane by 15 mV, but does not cause block of conduction nor does it inhibit the ACh effect. These observations are discussed and possible mechanisms of action are suggested.