Seyfert galaxies with linear nuclear radio structures have been studied with long-slit spectroscopy. Very extended, narrow [OIll] emission is detected in several of the objects, highly elongated along the radio source axis. This Extended Narrow Line Region would be consistent with interstellar gas that is photoionized by collimated energetic radiation from the nucleus. Within the Narrow Line Region detailed correspondences between [Olll] emission features and individual radio components have been found in a number of Seyfert galaxies. Velocities and positions of these [OIll] features suggest that they may be produced when ambient gas has been compressed by an outmoving radio component, subsequently cools down behind the bow shock and then is photoionized by the nuclear continuum source.