Background: Serotonin activity has been shown to be increased in the basal ganglia of patients with progressive supranuclear palsy (PSP), and may be responsible for its extrapyramidal features that do not respond to 1-dopa.
Objective: To investigate clinical effectiveness of 5-HT1A agonist, tandospirone citrate (TC), on various clinical features of PSP.
Method: Clinical signs of eight patients (2 women and 6 men) who fulfilled NINDS-SPSP criteria of PSP were studied before and after administration of TC. Each of vertical gaze palsy, apraxia of eyelid opening, neck dystonia, bradykinesia, postural instability, gait disturbances, dysarthria, dysphagia, and bladder disturbances was graded, and evaluated before, and two and four weeks after oral administration of TC 30 mg/day.
Results: TC was well tolerated in six patients for four weeks. The other two patients developed dizziness or liver dysfunction in the second week, and dropped out. Neck dystonia, postural instability, and bradykinesia were improved significantly in the fourth week. On the contrary, vertical gaze palsy, dysarthria, and dysphagia responded poorly to TC. Apraxia of eyelid opening was present in three patients, and was improved in two. Bladder disturbances were present in three patients, and did not respond to TC.
Conclusion: Among various clinical features in PSP, TC was effective preferentially on extrapyramidal ones. Suppression of serotonergic activities in the basal ganglia of PSP may be underlying in the effectiveness of this 5-HT1A agonist.