A Study on the Association between Polymorphism in Dopamine D_4 Receptor Gene and Psychiatric Diseases

1994 Fiscal Year Final Research Report Summary

• Project/Area Number: 05670797
• Research Category: Grant-in-Aid for General Scientific Research (C)
• Allocation Type: Single-year Grants
• Research Field: Psychiatric science
• Research Institution: University of Tokyo
• Principal Investigator: FUKUDA Masato University of Tokyo, Faculty of Medicine, Assistant, 医学部(病), 助手 (20221533)
• Co-Investigator(Kenkyū-buntansha): NIWA Shin-ichi Fukushima Medical College, Faculty of Medine, Professor, 医学部(病), 教授 (30110703) ; HIRAMATSU Ken-ichi University of Tokyo, Faculty of Medicine, Assistant, 医学部(病), 助手 (50218814) ; HONDA Makoto University of Tokyo, Faculty of Medicine, Assistant, 医学部(病), 医員 ; KODAMA Tatsuhiko University of Tokyo, Faculty of Medicine, Assistant, 医学部(病), 助手 (90170266)
• Project Period (FY): 1993 – 1994
• Keywords: dopamine receptor, / D_4 receptor gene, / psychiatric disease, / DNA polymorphism, / polymerase chain reaction (PCR)

Research Abstract

Dopaminergic system are assumed to play an important role in the etiology and the pathophysiology of many psychiatric diseases. Among five types of human dopamine receptors, cDNA polymorphism with repeated sequences has been demonstrated in D_4 receptor gene. The purpose of this syudy is 1) to establish an easy method to determine the polymorphism in D_4 receptor gene using white blood cell DNA,and 2) to investigate the association between the polymorphism and psychiatric diseases.
In 1993, amplification of D_4 receptor gene was conducted with polymerase chain reaction (PCR) method using three sets of primers. Specific amplification of D_4 receptor was unsuccessful because many other genes were amplified simultaneously. Survey of the relevant literatures showed that D_4 receptor gene is one of the most difficult one to be amplified by PCR.
In 1994, single band in the electrophoresis of PCR products was obtained with many technical improvement and PCR condition adjustment. The band probably represent the intended D_4 receptor gene because the band showed the same electrophoretic Pattern as that of D_4 receptor gene when digested by two different restriction enzymes. Therefore, the D_4 receptor gene is easily amplified with PCR method under the condition determined here. Now, the association between D_4 receptor gene polymorphism and psychiatric diseases is being investigated with the above method.