The effect of indomethacin on pelvic pressurre during ureteral obstruction in dogs induced plasma hyperosmolality and plasma hypoosmolality

Abstract

This investigation was performed to study the effects of indomethacin on pelvic pressure after unilateral ureteral obstruction in dogs induced different plasma osmolality. Twenty anesthetized dogs weighing between 10-15 kg. were divided into four groups. Animals in group I were induced plasma hyper osmolality by injection of 3% NaCl intravenously. In group II, animals were induced plasma hypo osmolality by 2.5% D/W, intravenous injection. Animals in group III were induced acute dehydration by furosemide 5 rag/kg.bw., intravenous injection. Animals in group IV were induced high level of ADH in plasma by Arginine vasopressin 1 unit administration intramuscularly. After unilateral ureteral obstruction, the solutions were given in each group before indomethacin administration. The results showed that after unilateral ureteral obstruction in each group, the pelvic pressure (pp) was elevated to 53 mm. Hg. There was no significant change in the general hemodynamics. In the study of contralateral renal function, it was found that renal vascular resistance (RVR) decreased 10% while urine flow rate (V) increased 19%. After hypertonic solution was administrated in group I, there was no effect on general circulation. It was found that RVR of the contralateral kidney was slightly decreased. increased approximately 78% and renal fraction (RF) increased 63%. In group II after hypotonic solution administration, the rate of urine flow of the contralateral control kidney and pelvic pressure of the experimental kidney did not change. Group III after furosemide injection, it was found that cardiac output (CO) decreased slightly. The rate of urine flow increased from 21.4±15.7 to 175.5±90 µl/min/kg.bw (p<0.05). RVR decreased 26% whereas RF increased 9%. In group IV after administration of ADH, CO and BV increased 31% and 9% respectively. Pelvic pressure of the experimental kidney did not change. The rate of urine flow of the contralateral control kidney decreased approximately 10%, RVR increased and RF decreased 33% after indomethacin (5 mg/kg.bw) was injected intravenously. The results of administration of indomethacin showed no significant changes in the general circulation in all groups as compared with pre-treated period. On the renal function study, urine flow rate of contralateral kidney decreased kb% in all groups. In group I and RF decreased slightly with a slight elevation of RVR. In group 1 II and IV there was no significant change in RVR. During administration of indomethacin, pelvic pressure of the experimental kidney in group I, III and IV decreased 43%, 22%, 17% and 8% respectively when compared with the period before indomethacin. These results interpret to conclude that unilateral ureteral obstruction enhanced prostaglandin activity, it caused the elevation of pelvic pressure and changed in the contralateral renal functions. During treatment with different solutions after ureteral obstruction. The balance of intracranial vasodilator hormones (e.g. prostaglandin) and vasoconstrictor hormone may be involved. Plasma hyper osmolality status may enhanced prostaglandin activity. When the inhibition of prostaglandin by indomethacin was used, a marked decrease in pelvic pressure was found. The other conditions, as plasma hypo osmolality, acute dehydration from furosemide and hydration status from ADH might not stimulate prostaglandin and renin-angiotensin activities, the great decrease in pelvic pressure was not shown.