Focused microwave irradiation-assisted immunohistochemistry to study effects of ketamine on phospho-ERK expression in the mouse brain.

•Focused microwave irradiation-assisted IHC assay used to detect phosphoproteins.•Tissue integrity and cell structure unaffected by focused microwave irradiation.•Ketamine and Ro 25-6981 produced dose and time dependent increase in phospho-ERK.•Mapped distribution pattern of phospho-ERK in response to ketamine and Ro 25-6981.