Dissociation between the effects of P1, P4-diadenosine tetraphosphate (Ap4A) on renal haemodynamics and tubular function in anaesthetized rats.
Previous studies from our laboratory have reported a marked reduction in glomerular filtration rate (GFR) and sodium reabsorption in renal proximal tubule during intravenous infusion of P(1),P(4)-diadenosine tetraphosphate (Ap(4)A) at dose of 1.0 micromol/kg + 10 nmol/kg/min (i.v., injection followed by infusion) in anaesthetized Wistar rats. In the present study, the changes of GFR and urine sodium excretion were investigated in response to systemic infusion of Ap(4)A at different doses. Ap(4)A at dose of 0.1 micromol/kg + 1.0 nmol/kg/min did not change GFR and sodium urinary excretion whereas 2-fold higher dose produced significant (3.4-fold) increase in sodium excretion without changes in GFR. Significant but transient reduction in GFR by approximately 21% was observed during infusion of Ap(4)A at dose of 0.5 micromol/kg + 5.0 nmol/kg/min. Higher doses of Ap(4)A (1.0 micromol/kg + 10 nmol/kg/min and 2.0 micromol/kg + 20 nmol/kg/min) reduction in GFR and marked natriuresis. Our results suggest that tubular sodium transport systems are more sensitive to Ap(4)A than systems involved in GFR regulation.
Jankowski
M
M
Department of Monitoring Therapy and Pharmacogenetics, Medical University of Gdańsk, Poland. majank@amg.gda.pl
Angielski
S
S
Szczepańska-Konkel
M
M
D000818:Animals; D015226:Dinucleoside Phosphates / Q000008:administration & dosage / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005919:Glomerular Filtration Rate / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects*; D007668:Kidney / Q000187:drug effects* / Q000378:metabolism; D007687:Kidney Tubules, Proximal / Q000187:drug effects / Q000378:metabolism; D008297:Male; D009318:Natriuresis / Q000187:drug effects*; D051381:Rats; D017208:Rats, Wistar; D012964:Sodium / Q000378:metabolism
D015226:Dinucleoside Phosphates; C020733:diadenosine tetraphosphate; D012964:Sodium