Dihydropyridine derivatives

The present invention relates to new dihydropyridine derivatives and the use of the dihydropyridine derivatives as medicines. The activation of N-type calcium channel is concerned with various diseases, for example, acute stage of ischemic cerebrovascular disorders caused by cerebral infarction or intracerebral bleeding (including subarachnoidal hemorrhage); progressive neurodegenerative diseases such as Alzheimer's disease, AIDS related dementia and Parkinson's disease, dementia due to cerebrovascular disorder and ALS; neuropathy caused by head injury; various pains such as pain caused by spinal injury, diabetes or thromboangiitis obliterans, postoperative pain, migraine and visceral pain; various diseases associated with psychogenic stress such as bronchial asthma, unstable angina and irritable colitis; emotional disorder and withdrawal symptoms after addiction to drugs such as ethanol addiction withdrawal symptoms. The compounds of the present invention can inhibit the activation of the N-type calcium channel and, therefore usable as therapeutic agents for these diseases. Dihydropyridine derivatives represented by the following formula: analogs thereof and pharmaceutically acceptable salts thereof have an activity of selectively inhibiting the action of N-type calcium channel, and they are used as therapeutic agents for various diseases relating to N-type calcium channel.