Kronik diabetik sıçanların kan basıncı ve damar yanıtları üzerinde L-arjinin tedavisinin geri döndürücü etkileri

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Thesis Type: Postgraduate

Institution Of The Thesis: Ankara University, Sağlık Bilimleri Enstitüsü, FARMAKOLOJİ ANABİLİM DALI, Turkey

Approval Date: 1999

Thesis Language: Turkish

Student: VOLKAN TAŞYARAN

Supervisor: ARİF TANJU ÖZÇELİKAY

Abstract:

61 SUMMARY Reversal Effects of L-arginine Treatment on Blood Pressure and Vascular Responsiveness of Chronic Diabetic Rats. In the present study, we examined the reversal effects of L-arginine treatment in vivo on blood pressure and on vascular responsiveness of chronic diabetic rats. 12 weeks after streptozotocin (STZ) injection, systolic plood pressures (SBP) of diabetic groups have been found to be significantly higher when compared with those of control group. L-arginine treatment for 4 weeks, begun 12 weeks after the onset of diabetes, induced a significant fall in SBP of diabetic rats. Maximal contractile response and sensitivity (pÜ2 value) of the aortae to phenylephrine (PE) were significantly enhanced in diabetic rats compared with controls. Treatment of diabetic rats with L-arginine completely reversed the increases in responsiveness and sensitivity of aorta to PE. Relaxation response to acethylcholine, but not to sodiumnitroprusside (SNP), in diabetic rat aorta has been found to be significantly decreased as compared with controls. The treatment with in vivo L-arginine reversed the decreased acethylcholine responses to the control level. Plasma malondialdehyde (MDA) level of diabetic rats was also significantly higher than controls. However, L- arginine treatment normalized the increase in MDA plasma level of diabetic rats. All of the effects of L-arginine treatment were found to be spesific for diabetic rats. These results show that in vivo L-arginine treatment has reversal effects on impaired vascular responses and increased oxidative stress. The present findings also suggest that arginine deficiency and oxidative stress occured in diabetes might cause or contribute to devolopment of hypertension by affecting vascular reactivity. On the other hand, lipid peroxidation lowering effect of L-arginine may account for its beneficial effect on SBP and vascular responsiveness of diabetic rats. Key Words: Aorta, Diabetic Rat, Hypertension, L-arginine, Lipid peroxidation, Vascular responses.