Health & Environmental Research Online (HERO)


Print Feedback Export to File
2818649 
Journal Article 
Inhibition of voltage-dependent potassium conductance by convulsant phenols in the medial giant axon of the crayfish (Astacus astacus) 
Kaila, K; Saarikoski, J 
1980 
Yes 
Comparative Biochemistry and Physiology - Part C: Comparative Pharmacology
ISSN: 0306-4492 
HEEP/80/11657 
65 
1 
17-24 
HEEP COPYRIGHT: BIOL ABS. The effects of phenol, 4-chlorophenol, 2,4-dichlorophenol, 2,4,6-trichlorophenol, pentachlorophenol, 3-methylphenol, 4-chloro-3,5-dimethylphenol, 2,4-dinitrophenol and 2,4,6-trinitrophenol on the crayfish A. astacus medial giant axon were studied using intracellular microelectrodes. Phenols which are largely nonionized at physiological pH produced a rather specific inhibition of voltage-dependent K conductance. The conductance inhibition declined during a prolonged depolarization. In experiments with variation in pH, the stationary component of the conductance inhibition was related to the concentration of the nonionized forms of the compounds. The weakly ionized phenols caused motor excitation and discoordination in intact crayfish. The more acid derivatives had a depressant effect. The excitatory behavioral effects of the weakly ionized phenols are at least partly due to the inhibition of voltage-dependent K conductance, which leads to a general facilitation of synaptic transmission by causing increased transmitter liberation from presynaptic terminals.