Effect of reserpine treatment on low-density lipoproteins in arterial walland internal organs of rats

The effects were determined in rats of single injections of reserpine at in creasing doses (0.5, 1.58, and 5.0 mg/kg) on low-density lipoprotein (LDL) and cholesterol in aortic wall, heart, liver, kidney, and adrenal gland. Ca techol amine levels in plasma, heart, and liver, arterial blood pressure, a nd heart rate were also monitored. Reserpine was injected intraperitoneally , followed immediately by the administration of [H-3]cholesterol by gavage. Twelve hours later, homologous I-125-tyramine cellobiose-labeled LDL ([I-1 25-TC-LDL) was injected intravenously. Twenty-four hours later, the rats we re killed, and the radioactivities of aortic walls, heart, liver, kidney, a nd adrenal glands were determined. The results showed that after reserpine treatment the accumulation of both the I-125-TC label derived from LDL and total [H-3]cholesterol was significantly reduced in aortic wall and heart, increased in liver, and unchanged in the kidney and adrenal gland. At highe r doses (1.58 and 5.0 mg/kg), reserpine significantly accelerated the plasm a clearance of radiolabelled LDL, Plasma noradrenaline in reserpine-treated animals decreased maximally (86%) by 12 h and by 61-71% at 36 h compared w ith the control. Plasma adrenaline increased transiently after injection of reserpine and then returned to the basal levels. Reserpine greatly decreas ed noradrenaline and adrenaline levels in heart and Liver. Arterial blood p ressure was decreased significantly (0.001 < p < 0.05) at 12 h by the two l ower doses of reserpine and then returned to normal values over the next 24 h. The results indicate that reserpine decreases LDL cholesterol in artery wall and heart and increases it in liver. These findings suggest that rese rpine could find a new use as a cholesterol-lowering drug for the preventio n of atherosclerosis.