Tonic and phasic influences of nitric oxide on renal blood flow autoregulation in conscious dogs
| Autor: | Armin Just, Uwe Wittmann, Heimo Ehmke, Hartmut R. Kirchheim |
|---|---|
| Rok vydání: | 1999 |
| Předmět: |
medicine.medical_specialty
Physiology Myogenic contraction Hemodynamics Blood Pressure S-Nitroso-N-Acetylpenicillamine Nitric Oxide Renal Circulation Nitric oxide Tonic (physiology) chemistry.chemical_compound Dogs Heart Rate Oscillometry Internal medicine medicine Animals Homeostasis Autoregulation Enzyme Inhibitors Tubuloglomerular feedback Penicillamine Snap Electrophysiology NG-Nitroarginine Methyl Ester Endocrinology chemistry Renal blood flow |
| Zdroj: | American Journal of Physiology-Renal Physiology. 276:F442-F449 |
| ISSN: | 1522-1466 1931-857X |
| DOI: | 10.1152/ajprenal.1999.276.3.f442 |
| Popis: | The aim of this study was to investigate the influence of the mean level and phasic modulation of NO on the dynamic autoregulation of renal blood flow (RBF). Transfer functions were calculated from spontaneous fluctuations of RBF and arterial pressure (AP) in conscious resting dogs for 2 h under control conditions, after NO synthase (NOS) inhibition [ NG-nitro-l-arginine methyl ester hydrochloride (l-NAME)] and afterl-NAME followed by a continuous infusion of an NO donor [ S-nitroso- N-acetyl-dl-penicillamine (SNAP)]. After l-NAME ( n = 7) AP was elevated, heart rate (HR) and RBF were reduced. The gain of the transfer function above 0.08 Hz was increased, compatible with enhanced resonance of the myogenic response. A peak of high gain around 0.03 Hz, reflecting oscillations of the tubuloglomerular feedback (TGF), was not affected. The gain below 0.01 Hz, was elevated, but still less than 0 dB, indicating diminished but not abolished autoregulation. Afterl-NAME and SNAP ( n = 5), mean AP and RBF were not changed, but HR was slightly elevated. The gain above 0.08 Hz and the peak of high gain at 0.03 Hz were not affected. The gain below 0.01 Hz was elevated, but smaller than 0 dB. It is concluded that NO may help to prevent resonance of the myogenic response depending on the mean level of NO. The feedback oscillations of the TGF are not affected by NO. NO contributes to the autoregulation below 0.01 Hz due to phasic modulation independent of its mean level. |
| Databáze: | OpenAIRE |
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