Potentiation and inhibition of nicotinic effects on striated muscle by the tetramine disulfide benextramine

Abstract

In low concentrations (0.3-3 muM) the tetramine disulfide benextramine (BHC; N,N'-bis[6-(o-methoxybenzylamino)-n-hexyl]cystamine) potentiated the contracture of the isolated frog rectus abdominis muscle caused by acetylcholine but in the presence of physostigmine or in a higher concentration (10 muM) it inhibited. Benextramine only inhibited the contracture caused by carbachol or butyrylcholine. The all-carbon analog of benextramine only inhibited the effect of acetylcholine. The inhibitory effects of benextramine and its carbon analog were noncompetitive and readily reversible but the potentiating effect of benextramine was not readily reversible.