Abstract
We give in this paper indications about the dynamical impact coming from the main sources of perturbation in biological regulatory networks. First, we define the boundary of the interaction graph expressing the regulations between the main elements of the network . Then, we search what changes in the state values on the boundary could cause some changes of states in the core of the system . After, we analyse the role of the mode of updating on the asymptotics of the network, essentially on the occurrence of limit cycles . Finally, we show the influence of some topological changes on the dynamical behaviour of the system