This work proposes a Metascheduler for GRID platforms based on the Interaction Protocols of the Multiagent Systems. These protocols use the paradigm of economic models to define the coordination mechanisms in agent communities. Specifically, in this work we use auction and tender economical models. We propose an adaptive Metascheduler for GRID platforms using these ideas. According to the number of available resources one of these models is used to coordinate the assignment of resources.