Synchronization and signaling are two common approaches used for coordination in duty-cycling wireless sensor networks. In this paper we analyze the trade off between these two approaches used for energy-efficient communication. Finally, we present Neighborhood-based Power Management (NPM), a hybrid MAC protocol that minimizes signaling overhead throughopportunistically gained knowledge about neighbor wakeup schedules. Unlike the synchronization-based MAC protocols, NPM does not require a priori knowledge of the wakeup schedules. Using only a minimal exchange of schedule information, NPM reduces the signaling overhead by combining adaptive preambling with its neighborhood wakeup mechanism. Our simulations show that NPM outperforms popular B-MAC , X-MAC  and SCP  protocols under all network conditions.