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Cardiorenal effects of infusion of uridine adenosine tetraphosphate (Up4A) to conscious rats: hypotension and electrolyte retention
Author(s) -
Bie Peter,
Madsen Ole,
Wolff Helle
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.5.a508-b
Subject(s) - heart rate , vasodilation , medicine , endocrinology , blood pressure , excretion , adenosine , chemistry , bolus (digestion) , anesthesia
When injected as a bolus into the circulation of isolated, perfused kidneys or into anesthetised rats, Up4A elicits vasoconstriction (Jankowski V. et al. Nature Med . 11 :, 2005). We have investigated the cardiorenal effects of intravenous infusion of Up4A in conscious rats provided with chronic catheters in both femoral vessels and the bladder. The rats were trained to stay in a plastic retainer for the duration of the experiment. Up4A in isotonic glucose was given as step‐up infusion at rates of 8 – 32 and 128 nmol/min per kg body mass for 30 min per rate. The lower doses had no effect on mean blood pressure, heart rate or renal functions. The highest dose caused a small, but highly consistent decrease in arterial pressure (114±3 to 108±3 mmHg, p<0.001, n=6) together with an increase in heart rate (461±17 to 489±13 bpm, p<0.001); both rebounded immediately after the infusion to 119±3 mmHg and 436±20 bpm, respectively. Concomitantly, sodium excretion decreased by >75% (1.11±0.52 to 0.24±0.07 μmol/min, p<0.05), and potassium excretion fell by some 60% (1.85±0.62 to 0.65±15 μmol/min, p<0.05). Urine flow was not significantly affected. It is concluded that in the conscious rat, a step‐up infusion of Up4A causes vasodilatation and electrolyte retention.