Acute hypocapnia blunts natriuretic and diuretic effects of atrial natriuretic factor in rats.
Recent studies suggest that the autonomic nervous system, when activated by respiratory alkalosis, may attenuate the renal effects of atrial natriuretic factor (ANF). We evaluated the renal responses to infusion of ANF during acute exposure to hypocapnia in the presence or absence of the renal nerves in anesthetized rats. In this study, renal function during hypocapnia was assessed and was compared with renal function during normocapnia produced by normal ventilation as well as by hyperventilation. Rats were divided into three experimental groups (n = 8): 1) a normally ventilated normocapnic (NV-N) (control) group; 2) a hyperventilated normocapnic (HV-N) group; and 3) a hyperventilated hypocapnic (HV-H) group. The innervated (Inn) right kidney served as a control for the contralateral denervated (DNX) kidney. In Inn and DNX kidneys of HV-H rats, an infusion of ANF (12 micrograms.kg-1.h-1) produced a smaller increase in urine flow rate (delta V: 9.8 +/- 3.9 and 1.3 +/- 4.2 microliters/min) and in fractional Na excretion (delta FENa: 1.35 +/- 0.52 and 0.73 +/- 0.58%) compared with NV-N rats (delta V: 37.6 +/- 4.9 and 59.9 +/- 9.7 microliters/min; delta FENa: 3.24 +/- 0.37 and 3.88 +/- 0.65%). No differences were observed in delta V and delta FENa in Inn kidney between HV-H and HV-N groups; however, the attenuated natriuretic and diuretic responses to ANF in DNX kidney of HV-H rats were also observed in comparison with HV-N rats (delta V: 27.4 +/- 4.3 microliters/min; delta FENa: 2.94 +/- 0.48%). ANF induced natriuresis in DNX kidney to the same degree in NV-N and HV-N rats.(ABSTRACT TRUNCATED AT 250 WORDS)
Mimura
Y
Y
Department of Physiology and Biophysics, Mayo Clinic and Foundation, Rochester, Minnesota 55905.
Khraibi
A A
AA
Heublein
D M
DM
Knox
F G
FG
D000818:Animals; D009320:Atrial Natriuretic Factor / Q000494:pharmacology*; D001794:Blood Pressure; D002245:Carbon Dioxide / Q000097:blood*; D003714:Denervation; D004231:Diuresis / Q000187:drug effects*; D005919:Glomerular Filtration Rate; D006985:Hyperventilation; D007668:Kidney / Q000187:drug effects / Q000294:innervation / Q000502:physiology*; D008297:Male; D009318:Natriuresis / Q000187:drug effects*; D010100:Oxygen / Q000097:blood; D051381:Rats; D017208:Rats, Wistar
D002245:Carbon Dioxide; D009320:Atrial Natriuretic Factor; D010100:Oxygen