AbstractThe effect of puromycin, puromycin‐aminonucleoside, cycloheximide and acetoxycycloheximide has been tested on the function of the superior cervical ganglion of rat, by recording the postganglionic response evoked by preganglionic stimulation. All the compounds examined exerted a depressant effect, which was prompt and reversible with puromycin and its aminonucleoside, but slow and irreversible with the glutarimides. A correlation of these effects with inhibition of protein synthesis has been examined. The relevance of these findings for experiments on memory disruption reported in the literature is discusse