|Budget Amount *help
¥2,100,000 (Direct Cost : ¥2,100,000)
Fiscal Year 1997 : ¥300,000 (Direct Cost : ¥300,000)
Fiscal Year 1996 : ¥400,000 (Direct Cost : ¥400,000)
Fiscal Year 1995 : ¥1,400,000 (Direct Cost : ¥1,400,000)
Occurrence of sudden cardiac death is considered to connect with arrhythmia. Such arrhythmia is believed to be evoked with exhaustion based on socio^psychological stress. On the other hand, soocio-psychological stress is a harmful factor in cardiovascular disease. However, correlation between occurrence of cardiovascular disease and socio-psychological stress is not unclear. One of the reasons may be that there is no an appropriate animal model of psychological stress-induced cardiovascular disease. The purpose of the present study is clarified wherher larding of psychological stress is capable of induction of cardiac abnormality, or not. Therefore, influence of psychological stress induced by the conditioned fear and the communication box methods on ECG in rats, is examined. Heart rate of rats with conditioned fear stredd kept to increase whenever they were reintroduced into the foot shock chamber. However, abnormal ECG was not found. ON the other hand, heart rate of rats with psychological stress-induced by the conmmunication box method increased whenever they received emotional response from foot shocked rats, and their deviation of R-R intervals enlarged. The enlargement of deviation of R-R intervals may by connected wuth arrhythmia. Then, using SHRSP (stroke-prone spontaneously hypertensive rats), influence of psychological stress induced by the communincation box method on ECG was investigated. The results showed that 19,23 and 34 weeks old SHRSPs showed arrhythmia ion proportion to length of stress-loading. Especially, the 34 weeks old SHRSP showed arrhythmia during the non-stressed period. Therefore, SHRSP may fall into cardiac disease, getting older.A beta_1-selective antagonist atenolol was ameliorated the arrhythmia. Thus, an animal model of spontaneously induced arrhythmia was developed using both SHRSP and psychological stress induced by the communication box method.