Feedback between host galaxy and nuclear activity

One of the main issues concerning Nuclear Activity in galaxies (AGN) is to understand the triggering mechanisms for the onset of non-thermal emission in their nuclei. Both the origin of the gas accreted onto the black hole and the physical mechanisms for the loss of angular momentum required for this funnelling to be eectiv e, have to be elucidated. In other words, the goal is to understand the necesary conditions to switch on the AGN activity. But many aspects of the investigation are still a matter of debate. Among them, the role played by gravitational interactions and the relevance of the host galaxy need to be claried. In this contribution, the different relationships between AGN activity, the morphological type of the host galaxy and the environment are discussed, in order to understand whether the AGN activity is more related to interacting eects or otherwise can be due to the secular evolution in the hosting galaxies.