Effect Ofβ-endorphin On Cardiovascular Functions In Chronic Renal Failure

The changes of intenal environment as a result of chronic renal failure(CRF)affect the cardiovascular and neuroendocrine systemwithin the body．Cardiovascular diseases asa consequece of CRF are the leading cause of death in CRF patients．However,The systematic study on the relationship between nemendocrine and CRF is rarelyreported so far．In this study,animal CRF modelwas established atfirst,and then the dynamic changes of β-endorphin(β-EP)levels,one of the important neurohormones,in the plasma,cardiac and renal tissues were observed in CRF rats．Inadition,the changes of plasmaβ-EP levels during hemodialysis and kidney transplantation in CRF patients were investigated as well with the aims of exploring the effect of β-EP on the cardiovascular function In CRF and itsmechanism．The main results are as follows:1．The model of experimental CRF was made by resection of5/6 ofrat kidney．Renalfunction deteriorated 14 weeks after operation with increased plasma uremlc nitrogen and creatlne,which peaked after 13 weeks,In the mean time urine volume(UV/24 hr)and urine sodium xiidischae(UNln)decreased and plasma osmolarlty Increased suggestingthe lmpalrmentofrenal clearance ofnltregen metabolltes,the concentfatinganddlMing劝llltyofthe renaltllbules 18 weeks after operation．2．Pathological examination of＊theation kidney and cardlac sections fromCRFRF rats with figN and electFomlcroscope showedthatthere were e＂largement ofrenal glomerule andprollferatlon of＊thellferatlon measanglumandmatrlx 14 weekspostopeftftlon．The caPlllvessels of＊thes glomerlWe were coensatlvelydlaltCdwlthfibrilatetelmgiomaformationl6 weeks postoperatlon．At 20th week,the local glomerulosclerosls with mesanglum vacuole degeneration was found．Pathological changes ofcardlac sections 20weeks after operation Include vacuole or granule degeneration,masslvemyocardlum Z－band bre,irregular organlzatlon of nuclear chromosome,dlsapearance of shrlnkagC of cellular nuclei一merstltlal edema上ymphocyte and neutfophll infiltration．3．Radiolmmunoassay(AIA)showed that the blood cencentratlon ofp ＝EP was maedly Increased ail6 the week．In addition,p一 EPwas also Increased Intheheartbutdecreased Inthe cones of＊the kidney 18 weeks after operation．4．The effects of Intravenous admlnstration of p—EP andanti－p—EP serum on the mean arterial pressure(MAP),heart rate(HR),left Ventrlcular systollc pressure(LVSP)and the irst derivative of the left ye X互11ntrlcular pressure(dp／dt max)were observed 20 weeks after operation．MAP,LVSIP,HR and dp／dt max were all decreased by p一EP in the control group,while MAP was Increased,LVSP and dp／dt max were decreased In CRFRF rats．Neutralization ofendogenous p一EP withanti－p一EP serum improved cardlac Indications such as dp／dt maxLVSPwith less luctllatlons of一 sugge stingthatthe changesofp一EP in C盯 rats have lmportanteffect on the cardiovascular unotion．5．The plasua levels of p一EP in C肛 patients were also medly Increased．After hemodlalysls,the p一EP concentration,plasma uremlc nitrogen,creatlne andosmolarltywere all decreased although still higher than normal volunteers,After kidney transplantation,日一EPevels were backto normal with improvement ofkldney function．The above results Indicated that the accumulated plasma p一EPduring C盯 as results of abnormal secretion,bredown ofp一EP Is oneof＊the一一 middle molecules with cardiovascularllblting effects．6．In order to urther Investigate the role ofp一EP In the regulation of blood pressure In C patients,p一EP concentrations In highand normal blood pressure patients were observed．In C patients...