Аннотация:A brief review of the investigation of chemically decoupled galactic nuclei in early-type galaxies performed with the Multipupil spectrograph of the 6 m telescope over the last ten years is presented. A relation of chemically decoupled stellar nuclei to the circumnuclear stellar disks is discussed. Some examples are demonstrated of the inner polar gas rings in morphologically undisturbed spiral galaxies - a phenomenon that we have first discovered and, possibly, connected with the origin of chemically decoupled nuclei. The first attempt has been made to statistically generalize the results of determination of the age and the ratio of magnesium and iron abundances in stellar populations of both chemically decoupled nuclei and bulges surrounding them.