We have measured the levels of kainate receptor mRNA in rat brains following the injection of antidepressant drugs over a time course up to 32 days. Over this period imipramine and fluvoxamine elicited a rise in kainate receptor mRNA levels to a maximum of three and two fold increase respectively, relative to untreated rat brain samples. Mianserin and amitriptyline did not induce significantly elevated kainate mRNA levels compared to untreated specimens, but were elevated compared to vehicle injected controls.