Combined Infusion Of Dopamine Research Articles

Role of renal dopamine D1 receptors in natriuresis induced by calcium channel blockers

The direct tubular natriuretic effect of calcium channel blockers (CCBs) may be due to an interaction between CCBs and a renal tubular dopamine receptor. We therefore studied the effects of two chemically unrelated CCBs, diltiazem and isradipine, infused into the right renal artery of 5% saline-loaded anesthetized rats alone or in the presence of a D1 antagonist, SKF-83742. Isradipine (0.03 microgram.kg-1.min-1) or diltiazem (20 but not 10 micrograms.kg-1.min-1) alone produced an increase in urine flow and an approximate doubling of absolute and fractional sodium excretion, which was not seen in the left kidney or in the control animals (analysis of variance, Scheffé's test, P < 0.05). SKF-83742 alone given systemically or into the right renal artery did not affect these parameters but did block the actions of diltiazem or isradipine. There was no change in mean arterial pressure, renal blood flow, or glomerular filtration rate in any of the experiments. In additional studies, we found that a combined infusion of dopamine (0.1 microgram.kg-1.min-1) and diltiazem (10 micrograms.kg-1.min-1) (doses that by themselves did not alter renal function) produced a twofold or greater increase in urine flow and absolute and fractional sodium excretion; glomerular filtration rate was not significantly changed. Intrarenal arterial CCBs, without a change in renal hemodynamics, produce a natriuresis that is blocked by a D1 antagonist. Concomitant administration of diltiazem and dopamine (each in subeffective doses when used alone) produces a synergistic effect.(ABSTRACT TRUNCATED AT 250 WORDS)

Impact of donor age on living related donor kidney transplantation.

Two comparable groups of kidney transplant recipients were identified according to the age of their kidney donors. The first group (A) comprised 42 recipients of donors aged < 40 years, and the second group (B) comprised 48 recipients of donors aged > 50 years. The patients were followed for a mean period of 26 months (range 13-50 months). Post-transplant renal function and graft survival were assessed together with the frequency of post-transplant proteinuria and hypertension. Moreover, the functional reserve of the grafts was determined by comparing the clearance values, obtained by both isotope and chemical means, before and after a combined infusion of dopamine and an amino acids preparation. The graft function was significantly better in group A according to the serum creatinine levels (micromol/l) at 1 month (107+/-4.5 vs. 134+/-10.7, P < 0.01), 12 months (119+/-5.3 vs. 181+/-88, P < 0.05) and at last follow-up visit (118+/-6.2 vs. 223+/-63, P < 0.03) for groups A and B, respectively. The graft survival in group A was significantly higher than that in group B (100% vs. 87% at 1 year, P < 0.05). The graft functional reserve was significantly better in group A than in group B. Post-transplant proteinuria was significantly more frequent in group B recipients (70% vs. 40%, P < 0.03). The age of the donors had no impact on the incidence of post-transplant hypertension. These observations suggest that the transplantation of a kidney from an older live kidney donor is associated with an inferior post-transplant outcome.

Impact of donor age on living related donor kidney transplantation

Two comparable groups of kidney transplant recipients were identified according to the age of their kidney donors. The first group (A) comprised 42 recipients of donors aged < 40 years, and the second group (B) comprised 48 recipients of donors aged > 50 years. The patients were followed for a mean period of 26 months (range 13–50 months). Post-transplant renal function and graft survival were assessed together with the frequency of post-transplant proteinuria and hypertension. More-over, the functional reserve of the grafts was determined by comparing the clearance values, obtained by both isotope and chemical means, before and after a combined infusion of dopamine and an amino acids preparation. The graft function was significantly better in group A according to the serum creatinine levels (µmol/l) at 1 month (107 ± 4.5 vs. 134 ± 10.7, P < 0.01), 12 months (119 ± 5.3 vs. 181 ± 88, P < 0.05) and at last follow-up visit (118 ± 6.2 vs. 223 ± 63, P < 0.03) for groups A and B, respectively. The graft survival in group A was significantly higher than that in group B (100 % vs. 87 % at 1 year, P < 0.05). The graft functional reserve was significantly better in group A than in group B. Post-transplant proteinuria was significantly more frequent in group B recipients (70 % vs. 40 %, P < 0.03). The age of the donors had no impact on the incidence of post-transplant hypertension. These observations suggest that the transplantation of a kidney from an older live kidney donor is associated with an inferior post-transplant outcome.

Renal reserve filtration capacity before and after kidney donation

Renal reserve filtration capacity (RRFC) was investigated in 20 kidney donors before and within 3 months after uninephrectomy. Glomerular filtration rate (GFR) was measured by the clearance of 125I-iothalamate, and effective renal plasma flow (ERPF) was determined by the clearance of 131I-hippurate. RRFC was tested by infusion of a low dose of dopamine, by intravenous administration of an amino acid solution and, finally, by combined infusion of amino acids and low-dose dopamine. After kidney donation, the median value of the GFR was 65% of its initial value. The median value of the ERPF was 69% of its value before uninephrectomy. The filtration fraction declined significantly from 0.251 to 0.238 (medians; P less than 0.02). Median values for dopamine-induced increases in GFR were 13.8% before and 5.3% after kidney donation (P less than 0.005). Infusion of amino acids led to an increase in GFR of 11.2% before and 9.6% after donation (NS). During combined infusion, the median values for the increases in GFR were 20.0% before and 12.6% after uninephrectomy (P less than 0.02). Median changes in ERPF before and after kidney donation were 33.4 vs. 23.0% during dopamine infusion (P less than 0.005), 10.0 vs. 8.3% during amino acid infusion (NS), and 36.2 vs. 24.3% during the combined infusion of dopamine and amino acids (P less than 0.02). Infusion of dopamine induces a decrease in renal vascular resistance, resulting in a rise in glomerular blood flow. Since RRFC tested by means of dopamine infusion was significantly decreased after kidney donation, it is concluded that glomerular hyperfiltration after kidney donation is at least partially due to a rise in glomerular blood flow.

Dopamine and saralasin antagonism of renal vasoconstriction and oliguria caused by amphotericin B in dogs.

Amphotericin B (2.5 mg/kg, administered intravenously) increased vascular resistance (renal more than pulmonary more than systemic) and decreased glomerular filtration and urine flow 94% in 16 anesthetized female mongrel dogs. Dopamine decreased renal vascular resistance 31% in 14 dogs; when amphotericin B was given with dopamine, there was partial antagonism of amphotericin B-induced renal vasoconstriction. Saralasin partially antagonized amphotericin B-induced renal vasoconstriction in seven dogs. When amphotericin B was given during combined infusion of dopamine and saralasin in eight dogs, renal blood flow remained at initial control levels, urine flow increased above initial levels, and glomerular filtration decreased only 21% from initial values. Amphotericin B increased renal vascular resistance 296% when given alone but only 41% in dogs during injection of both dopamine and saralasin (P = 0.002). The antagonism of amphotericin B-induced renal effects by the combination of dopamine and saralasin was significant and specific for the renal vascular bed.

Haemodynamic effects of dopamine, epinephrine and orciprenaline (Alupent®) in patients early after cardiac surgery

The haemodynamic effects of Dopamine (100, 250 and 500 mcg/min), Epinephrine (4 and 8 mcg/min), Orciprenaline (4 and 8 mcg/min) and two combinations of Dopamine 250 mcg/min with Epinephrine and Orciprenaline 4 mcg/min respectively at constant infusion rates were studied in 21 patients after cardiac surgery. Special attention was payed to four types of catecholamine infusions during which the highest cardiac index (CI), 161-168% of control, was seen: Dopamine 500 mcg/min (D 500), Epinephrine 8 mcg/min (E 8), Dopamine 250 mcg/min combined with Epinephrine 4 mcg/min (D 250 + E4) and Dopamine 250 mcg/min combined with Orciprenaline 4 mcg/min (D 250 + Or 4). At the same time mean arterial pressure (MAP) was highest with D 500 (137%) and lowest during both combined infusions (120 and 125%). Total peripheral resistance (TPR) was lowest during the combined infusions (80 and 81% of control) and highest during D 500 (89%). The relative increase of stroke index (SVI) and heart rate (HR) in favor of SVI, given as a quotient SVI/HR, was highest with D 250 + E4(3.7), followed by E 8 (1.9), D 500 (1.6) and D 250 + Or 4 (1.3). It was concluded that a combined infusion of Dopamine and Epinephrine, both in low doses, is preferable to a high dose of Dopamine, or Epinephrine alone, producing the same increase of cardiac output with less afterload and less chronotropic effect than high doses of either drug alone.