This chapter will review the basic pharmacology of the canonical cannabinoid receptors. The endocannabinoid system is a complex signalling network involved in a wide range of physiological processes, including pain modulation, appetite regulation, and synaptic plasticity. The canonical cannabinoid receptors, CB1 and CB2, are central in orchestrating this system. CB1 is highly enriched in the central nervous system (CNS), where it plays a crucial role in modulating neurotransmitter release and synaptic plasticity. In contrast, CB2 is predominantly expressed in peripheral tissues and immune cells, participating in anti-inflammatory processes. Here, we focus on cannabinoid receptor distribution, intracellular signalling, and receptor regulation. We describe the intracellular signalling pathways activated by CB1, including the modulation of ion channels, second messengers, and protein kinases. Overall, this chapter provides an overview of the canonical cannabinoid receptors and their role in the regulation of neuronal signalling and plasticity, highlighting the molecular and cellular mechanisms underlying their effects in the CNS.