Differential effects of alcohols on the spike threshold of an identified motor axon in a crab (Pachygrapsus crassipes).
Observations were made on the fast bender excitor (FBE) axon in autotomized crab limbs bathed in salines made up with different alcohols. It has been shown previously that the presence of ethanol at a certain level causes a single action potential to generate additional spikes in the peripheral axon branches. The present study examines the level of different alcohols required to induce peripheral spike generation. For primary alcohols, increasing the molecular weight decreased the level of alcohol required to produce peripheral spike generation. The threshold level of 2-butanol was greater than 1-butanol, but less than tertiary-butanol. These results are explained in terms of the partition coefficient, so that an alcohol with a higher partition coefficient enters the lipid bilayer more readily, thus a lower threshold level of that alcohol is required in the saline to generate additional spikes.
Stephens
P J
PJ
Villanova University, Department of Biology, PA 19085.
D000200:Action Potentials / Q000187:drug effects; D000438:Alcohols / Q000494:pharmacology*; D000818:Animals; D001369:Axons / Q000187:drug effects*; D003386:Brachyura / Q000502:physiology*; D066298:In Vitro Techniques; D008970:Molecular Weight; D009046:Motor Neurons / Q000187:drug effects*; D013329:Structure-Activity Relationship; D013696:Temperature
D000438:Alcohols