SB 258585 hydrochloride is primarily used in neuroscience research as a potent and selective antagonist for the 5-HT6 receptor. Its main application lies in studying the role of serotonin receptors in cognitive functions and neurodegenerative diseases. Due to its high selectivity, it is employed in experimental models to investigate potential treatments for conditions such as Alzheimer's disease, schizophrenia, and other cognitive impairments. It has also been used to examine the effects of 5-HT6 receptor blockade on memory, learning, and behavior in preclinical studies. Its ability to cross the blood-brain barrier makes it particularly valuable in central nervous system research.