Dopamine D2 Receptor효능제인 TNPA의 신장작용

Renal Action of TNPA, a Dopamine D2 Receptor Agonist, in Dog

The dopaminergic receptors were considered of two distinct subtypes, D1 and D2, each having different fuction. The present study was attempted to investigate the effects of R(-)-2,10,11-trihydroxy-N-n-propylnoraphine(TNPA), a dopamine D2 against, on renal function in dog. TNPA decrease in osmolar clearance(Cosm) and urinary excretion of sodium and potassium(ENa and EK. It also increased reabsorption rates of sodium and potassium in renal tubules(RNa, RK) without any changes in glomerular filtration rate(GFR), renal plasma flow(RPF) and free water clearance(CH2O). TNPA(0.5~1.5 mcg/kg/min) infused into a renal artery decrease urine flow both in the experimental and control kidneys. TNPA(1.5-5.0mcg/kg) administered via the carotid artery also greately exhibitied antidiuresis even at intraveously ineffective doses. Changes of renal function by TNPA given into both renal artery and the carotid artery were almost the same aspect to those induced by intraveonous TNPA. These results obtained from the present study suggest that TNPA produces antidiuresis by increasing the reabsorption rates of electrolytes ub renal tubules, mainly distal tubule, through changing of central fuction.