Ouabain octahydrate is primarily used in biological and medical research due to its ability to inhibit the sodium-potassium ATPase pump. This inhibition disrupts ion transport across cell membranes, making it a valuable tool for studying cellular processes, ion channel functions, and the role of the Na+/K+ pump in various physiological conditions. It is also employed in experimental models to investigate cardiac physiology, as it can affect heart muscle contraction and electrical activity. Additionally, ouabain octahydrate has been explored in studies related to cancer research, where its effects on cell signaling pathways and apoptosis are of interest. Its application extends to neurobiology, where it helps in understanding the mechanisms of neurotransmitter regulation and neuronal excitability.