Isoarecolone methiodide is one of the most potent nicotinic agonists known at the frog neuromuscular junction and in inhibiting [3H] nicotine binding in rat brain membranes. 3,4-Dihydroisoarecolone methiodide and 2,2-dimethyl-5-ketodecahydroisoquinolinium iodide, though structurally similar, were less active. Minimum energy conformations of these ligands were calculated by molecular modeling. 2-Phenylbenzoates of open-chain aminoalcohols and 1-methyl-4-piperidonol had anticonvulsant activities comparable to that of phenytoin in a maximal electroshock seizure assay. Models show certain structural similarities between these esters and phenytoin. Both classes antagonize the binding of a batrachotoxin analogue to sodium channel sites.