Renal hemodynamic responses to dynamic exercise in rabbits.
Cardiovascular hemodynamics, including renal blood flow, were measured in rabbits with one intact and one denervated kidney during various intensities of treadmill exercise. Within the first 10 s of exercise, there was rapid vasoconstriction in the innervated kidney associated with decreases in renal blood flow (range -10 to -17%). The vasoconstriction in the innervated kidney was evident at all workloads and was intensity dependent. There was no significant vasoconstriction or change in renal blood flow (range 0.5 to -3.1%) in the denervated kidney at the onset of exercise. However, a slowly developing vasoconstriction occurred in the denervated kidney as exercise progressed to 2 min at all workloads. Examination of responses to exercise performed under alpha-adrenergic blockade with phentolamine (5 mg/kg iv) revealed that the vasoconstriction in the innervated kidney at the onset of exercise and the delayed vasoconstriction in the denervated kidney were due primarily to activation of alpha-adrenergic receptors. In addition, a residual vasoconstriction was also present in the innervated kidney after alpha-adrenergic blockade, suggesting that, during exercise, activation of other renal vasoconstrictor mechanisms occurs which is dependent on the presence of renal nerves.
Mueller
P J
PJ
Departments of Anesthesiology and Physiology, Medical College of Wisconsin and Veterans Affairs Medical Center, Milwaukee, Wisconsin 53295, USA.
O'Hagan
K P
KP
Skogg
K A
KA
Buckwalter
J B
JB
Clifford
P S
PS
D000316:Adrenergic alpha-Agonists / Q000494:pharmacology; D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000818:Animals; D001794:Blood Pressure / Q000502:physiology; D003714:Denervation; D005260:Female; D005557:Formaldehyde / Q000494:pharmacology; D006339:Heart Rate / Q000187:drug effects / Q000502:physiology; D007668:Kidney / Q000294:innervation; D009638:Norepinephrine / Q000378:metabolism; D010656:Phenylephrine / Q000494:pharmacology; D005082:Physical Exertion / Q000502:physiology*; D011817:Rabbits; D011942:Receptors, Adrenergic, alpha / Q000187:drug effects / Q000502:physiology; D012018:Reflex / Q000502:physiology; D012079:Renal Circulation / Q000187:drug effects / Q000502:physiology*; D014661:Vasoconstriction / Q000187:drug effects / Q000502:physiology
D000316:Adrenergic alpha-Agonists; D000317:Adrenergic alpha-Antagonists; D011942:Receptors, Adrenergic, alpha; D005557:Formaldehyde; D010656:Phenylephrine; D009638:Norepinephrine