Acute environmental stress overrides cardiac volume receptor reflex in borderline hypertensive rats.
OBJECTIVE
To examine whether acute environmental stress (air-jet stress) modulates the exaggerated natriuresis to volume expansion in conscious borderline hypertensive rats.


METHODS
Intravenous isotonic saline volume expansion was performed with and without superimposed acute air-jet stress in conscious borderline hypertensive rats which had consumed a 1% NaCl diet (normotensive) or an 8% NaCl diet (hypertensive) for 12 weeks.


METHODS
Conscious rats were instrumented for measurement of arterial pressure, renal sympathetic nerve activity and collection of bladder urine.


RESULTS
Arterial pressure was greater in the 8% NaCl borderline hypertensive rats than in the 1% NaCl borderline hypertensive rats. In the absence of acute air-jet stress the 8% NaCl borderline hypertensive rats exhibited exaggerated natriuresis and exaggerated inhibition of renal sympathetic nerve activity compared with the 1% NaCl borderline hypertensive rats. Acute air-jet stress increased both arterial pressure and renal sympathetic nerve activity reversibly, and attenuated natriuresis in the 8% NaCl but not in the 1% NaCl borderline hypertensive rats.


CONCLUSIONS
Acute environmental stress (air-jet stress) attenuates exaggerated natriuresis in hypertensive but not in normotensive borderline hypertensive rats via increased renal sympathetic nerve activity.
DiBona
G F
GF
Department of Internal Medicine, University of Iowa College of Medicine, Iowa City 52242, USA.
Jones
S Y
SY
D000208:Acute Disease; D000388:Air; D000818:Animals; D017704:Baroreflex / Q000187:drug effects / Q000502:physiology*; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology; D004525:Efferent Pathways / Q000503:physiopathology; D004777:Environment; D006321:Heart / Q000503:physiopathology*; D006973:Hypertension / Q000503:physiopathology* / Q000652:urine; D007262:Infusions, Intravenous; D007668:Kidney / Q000294:innervation / Q000378:metabolism / Q000503:physiopathology; D008297:Male; D009318:Natriuresis / Q000502:physiology*; D051381:Rats; D012965:Sodium Chloride / Q000009:adverse effects; D013312:Stress, Physiological / Q000503:physiopathology* / Q000652:urine; D013564:Sympathetic Nervous System / Q000503:physiopathology
D012965:Sodium Chloride