Methoctramine hydrate is primarily used in pharmacological research as a selective antagonist for muscarinic acetylcholine receptors, particularly the M2 subtype. It is instrumental in studying the role of these receptors in various physiological processes, such as heart rate regulation and smooth muscle contraction. Researchers utilize it to explore the therapeutic potential of modulating muscarinic receptors in conditions like cardiovascular diseases, asthma, and gastrointestinal disorders. Its specificity makes it a valuable tool for dissecting the functions of different receptor subtypes in experimental models.