A1651 TAURINE IMPROVES REDUCED RENAL MEDULLARY BLOOD FLOW IN SPONTANEOUSLY HYPERTENSIVE RATS

Abstract

Objectives: Present study was carried out to clarify the effect of renal nerve stimulation on renal cortical and medullary blood flow and the effects of chronic treatment of taurine on altered renal cortical and medullary blood flow distribution by renal nerve stimulation in spontaneously hypertensive rats (SHR). Methods: We used 6–7 (young) and 16–17 week old (adult) SHR and divided to taurine treated group and control group. Renal nerve surround left renal artery was stimulated electrically by 2, 5, 10 and 15 Hz under the anesthesia of isoflurane. Renal blood flow was measured using laser tissue flow meter using noncontact prove for cortical blood flow and contact glass-fiber needle type of prove for medullary flow. After a series of electrical stimulation, 1 mg of LNAME was injected and same protocol was repeated. Results: High frequency stimulation caused transient cortical blood flow elevation and which was followed by decrease of blood flow in young and adult WKY. In contrast, blood flow in renal medulla showed no significant changes compared with that in cortex. Young SHR showed a decrease of cortical and medullary blood flow by nerve stimulation. In adult SHP, blood flow reduction was similar to young SHR and medullary blood flow was more reduced than that in young rats. In adult WKY and young SHR, LNAME augmented the reduction of medullary blood flow by electrical stimulation. In adult SHR, LNAME showed no effects on blood flow reduction in medulla. Chronic treatment of taurine blunted the reduction of blood flow by electrical stimulation in medulla but not in cortex of adult SHR. Conclusion: Medullary blood flow is protected through the nitric oxide production in normotensive rats but this mechanism is blunted in SHR. Taurine could improve the reduction of renal medullary blood flow in aged SHR.