| Objective: Dopamine possesses the contribution of right inotropism and variability. It affects fast and the half life short. The contribution of relaxation to arteria renalis of dopamine have been demonstrated to be dose dependent. The administration of renal dose dopamine(RDA)for the improving of renal function became widespread with the 1964 publication of"Dopamine: Clinical Uses of an Endogenous Catecholamine"by Leon Goldberg. Schwartz report that low-dose dopamine can increase glomerular filtration rate, renal blood flow and to produce diuresis but dose not cause right inotropic effect in 1997.so-called RDA possesses the specificity effect of improving renal function. But recently, with dopamine use become widely and people study it become deeply. The use of RDA especially its mechanism of action on kidney, has become a controversial issue. Many studies sign that the effect of dopamine on kidney can not to be separated from hemodynamic. The experiment result in vivo show that RDA also quicken the heart rate when improving the renal function and renal blood flow .It cue that the effect of RDA improving renal function and renal blood flow with the effect of whole body effect. It need more study that the mechanism of action of RDA on renal. We approach the relationship of RDA on renal function and haemodynamic, through the different effection of RDA and dobutamine on kidney in vivo; we observe the unfold and shorten effect of renal vessel and the effection on kidney after administration of RDA, through the technology of IPK. So that we can get more detail information about RDA on kidney, to offer experimental evidence for clinical.Methods: The entrance standard for this study was healthy male rabbits who came from experimental animal center of He Bei Medical University. The rabbit(1.52.5kg)were randomized into two big groups and seven small groups with 6 rabbits in each group. In vivo:Intra-venous dopamine(the treatment groups 10μg·kg-1·min-1), Intra-venous dobutamine (the treatment groups 10μg·kg-1·min-1)and saline(the control group)were administrated after anesthesia. To study the effecion of haemodynamics in kidney In exvivo:norepinephrine(NE)( the treatment groups, perfused different density of norepinephrine), RDA(the treatment groups, perfused both RDA and NE), haloperidol(the treatment groups perfused all NE, renal dose dopamine and haloperidol)and saline(the control group ) were administrated after anesthesia. The establishment of animal model in vivo: all experimental animals are anesthetized by urethane, through intravenous by ear.The concentration of inulin in the fluid were 1.0g/L Carotid artery catheter was used to monitor mean heart rate, and performed continuous measurement of these indexes in experimental stage. The pin was detained in the ear to transfuse and the demeure was cathetered to collect urine aliquot. We also sampled urine for the measurement of inulin clearance and others at preset intervals. Renal Glomerular filtration rate(GFR)was calculated as inulin clearance. The dates were corrected by weight level. Colorimetric assay was used for determination of inulin clearance. Blood Na+ and urine Na+ were measured by biochemical analyzer of BeckmanCx-7. fractional Excretion of sodium(FENa)were calculated by formula. The establishment of animal model in exvivo: liberate the left ureter, arteroa renalis and renal vein then leave the kidney in the rabbit belly to keep temperature. To perfuse from the arteroa renalis ane the demeure was cathetered to collect urine aliquot. after anesthesia. The data were analyzed with SPSS for windows 11.5 statistic software and presented by mean and standard difference. The difference between groups were analyzed by analysis of variance (ANOVA).The correlation-ship was analyzed by Pearson method.Results:1 The effection of RDA and DOB on rabbit kidneyStatistical results showed that there are significant differences between control group and the test(P<0.05)in heart rate. Significant increment of FENa and urine volume were observed after the intravenous administration of dopamine(P<0.05, compared to dobutamine group).There are no significant differences between dobutamine group and the RDA (P<0.05) on glomerular filtration rate.2 The responsibility of vessels of kidney to NE in IPK.Vessel of kidney has fan responsibility, and keep steady in 180min. RDA has a evident relaxation on renal vessel, and it can be block up by haloperidol3 The effect of RDA on urine volume in IPK of rabbitThe urine volume keeps stable in the control group. Urine volume increased gradually, rised peak value at 60min after administration of RDA(P<0.05).4 The effect of RDA on FENa in IPK of rabbitFractional excretion of sodium rised immediately, and had statistics difference with before administration(P<0.05).5 The correlation of urine volum, and FENaThere is significant positive correlation between FENa and urine volum.(P<0.01).The result implys FENa is gradual increasing with increasing urine volum.6 After administration the change of IPK, PP, GFR and RA in isolated perfused rabbit kidney following the time, perfusion pressure were descend significantly than before administration(P<0.05).Both GFR and renin activity were similar in before and after administration(P<0.05)Conclusions:RDA can decreased significantly sodium reabsorption but rise urine flow. RDA had no effect on GFR or renin activity Thus indicate that RDA can increase urinary production through decreasing FENa But can not increase GFR through improving renal blood flow. The effect of RDA on kidney are concerned with allover the body.
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