Trace amines (ethylamine, octopamine, and tryptamine) stimulate inositol phospholipid hydrolysis in rat cerebral cortex slices.

Ethylamine, octopamine, tryptamine, and carbachol stimulate inositol phosphate accumulation in a dose-dependent way in rat cortical slices. Tyramine at 100 microM has no effect. The major inositol phosphate that is accumulated following stimulation is the monophosphate. The effect of carbachol is blocked by atropine but not by cyproheptadine, phenoxybenzamine, haloperidol or propranolol. None of the antagonists tried, including atropine, had an effect on the stimulation caused by ethylamine, octopamine or tryptamine.