Abstract: The present invention relates to compounds expected to be useful in the prevention and/or treatment of diseases such as amyotrophic lateral sclerosis, frontotemporal dementia, chronic traumatic encephalopathy, Alzheimer's disease, frontotemporal lobar degeneration, multisystem proteinopathy and the like, a method for preventing or treating such diseases, and the like.

Abstract: The present invention provides a compound having a glucosylceramide lowering action (e.g., promoting glucosylceramide metabolism, inhibition of glucosylceramide synthesis, promoting glucosylceramide catabolism, etc.), which is expected to be useful as an agent for the prophylaxis or treatment of lysosome diseases (e.g., Gaucher's disease), neurodegenerative diseases (e.g., Parkinson's disease, Lewy body dementia, multiple-system atrophy) and the like. The present invention relates to a compound represented by the formula (I): wherein each symbol is as described in the specification, or a salt thereof.

Abstract: The present invention provides a compound having a glucosylceramide synthase inhibitory action, which is expected to be useful as an agent for the prophylaxis or treatment of lysosomal storage diseases (e.g., Gaucher's disease, Fabry's disease, GM1-gangliosidosis, GM2 activator deficiency, Tay-Sachs disease, Sandhoffs disease), neurodegenerative diseases (e.g., Parkinson's disease, Lewy body dementia, multiple-system atrophy) and the like. The present invention relates to a compound represented by the formula (I): wherein each symbol is as described in the description, or a salt thereof.

Abstract: The present invention provides a compound having a glucosylceramide synthase inhibitory action, which is expected to be useful as an agent for the prophylaxis or treatment of lysosomal storage diseases (e.g., Gaucher's disease, Fabry's disease, GM1-gangliosidosis, GM2 activator deficiency, Tay-Sachs disease, Sandhoffs disease), neurodegenerative diseases (e.g., Parkinson's disease, Lewy body dementia, multiple-system atrophy) and the like. The present invention relates to a compound represented by the formula (I): wherein each symbol is as described in the description, or a salt thereof.

Abstract: A heterocyclic compound that can have an antagonistic action on an NMDA receptor containing the NR2B subunit, and is expected to be useful as a prophylactic or therapeutic agent for depression, bipolar disorder, migraine, pain, peripheral symptoms of dementia and the like is provided. A compound represented by the formula (I): wherein each symbol is as described in the DESCRIPTION, or a salt thereof.

Abstract: The present invention provides a compound having a glucosylceramide lowering action (e.g., promoting glucosylceramide metabolism, inhibition of glucosylceramide synthesis, promoting glucosylceramide catabolism, etc.), which is expected to be useful as an agent for the prophylaxis or treatment of lysosome diseases (e.g., Gaucher's disease), neurodegenerative diseases (e.g., Parkinson's disease, Lewy body dementia, multiple-system atrophy) and the like. The present invention relates to a compound represented by the formula (I) wherein each symbol is as described in the specification, or a salt thereof.