All issues > Volume 38(7); 1995

Original Article

J Korean Pediatr Soc. 1995;38(7):955-962. Published online July 15, 1995.

Effects of Cyclosporine on the Renal Sympathetic Nerve Activity and Baroreflex Function in Rabbits

Chan Uhng CU Joo¹, Tae Hee TH Park¹, Moon Hwan MH Lee¹, Jung Soo JS Kim¹

¹Department of Pediatrics, School of Medicine, Institute for Medical Science Chonbuk National University, Chonju, Korea

Abstract

Purpose
: The immunosuppresive drug cyclosporine(CS) is a novel agent that has greatly enhanced long-term survival after organ transplantation and has proved beneficial in the treat-ment of many autoimmune diseases. However, CS has emerged as a new cause of hypertens-ion. Although the causes of the hypertension are undoubtedly multifactorial, there are evidenc-es to suggest that sympathetic overactivity is involved. We postulate that hypertension associa-ted with CS is due to an upward resetting in sympathetic nerve activity which is seen in angio-tensin II induced hypertension. The purpose of this study is to evaluate the effects of cyclosp-orine on the renal sympathetic nerve activity and baroreflex function.
Methods
: Studies were performed in conscious rabbits(n=12) previously instrumented with arterial and venous catheters and renal nerve electrodes. Arterial baroreflex curves relating renal sympathetic nerve activity (RSNA) and heart rate(HR) to mean arterial pressure(MAP) were determined by producing ramp increased(i.v. phenylephrine) and decreases(i.v. nitroglyc-erin)in MAP.
Results
: In rabbits, CS(20 mg/kg i.v. 30 mm) produced significant increases in RSNA(100 to 181.3 10.3%, p<0.05), but did not increase MAP or HR. CS treatment produced a shift of the mid-range of the baroreflex control of RSNA(78.91 4.14 to 92.5 3.67) and of HR(80.18 3.9 to 95.4 13.9). CS had no effect on the maximum value of RSNA, or maximum gains of the these reflexes.
Conclusion
: These data suggests that the sympathoexcitatory response to CS involves an upward resetting of the arterial baroreflex function.

Keywords :Cyclosporine, Sympathetic nervous system, Baroreflex