Pericyte regulation of renal medullary blood flow.
Pericytes are contractile smooth muscle-like cells that surround descending vasa recta (DVR) and provide their capability for vasomotion. The importance of the medullary pericyte derives from the role of DVR to distribute most or all of the blood flow from juxtamedullary cortex to the renal inner and outer medulla. Physiological processes that are likely to be influenced by pericyte constriction of DVR include the urinary concentrating mechanism and pressure natriuresis. Oxygen tensions in the medulla are low, so that subtle variation of pericyte vasomotion might play a role to abrogate hypoxia and prevent insult to the medullary thick ascending limb of Henle. Known vasoconstrictors of DVR include angiotensin II, endothelins, norepinephrine, acetylcholine, and adenosine. Vasodilators include prostaglandin E2, adenosine, acetylcholine, bradykinin, and nitric oxide.
Pallone
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Division of Nephrology, University of Maryland School of Medicine, Baltimore, Md 21201-1595, USA. tpallone@medicine.umaryland.edu
Silldorff
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D000818:Animals; D005544:Forecasting; D006801:Humans; D007671:Kidney Concentrating Ability; D007672:Kidney Cortex / Q000098:blood supply; D007679:Kidney Medulla / Q000033:anatomy & histology / Q000098:blood supply* / Q000378:metabolism; D008833:Microcirculation / Q000033:anatomy & histology / Q000187:drug effects; D010100:Oxygen / Q000378:metabolism; D020286:Pericytes / Q000187:drug effects / Q000502:physiology* / Q000648:ultrastructure; D012079:Renal Circulation / Q000187:drug effects; D014662:Vasoconstrictor Agents / Q000097:blood / Q000494:pharmacology; D014665:Vasodilator Agents / Q000097:blood / Q000494:pharmacology; D014666:Vasomotor System / Q000033:anatomy & histology* / Q000187:drug effects
D014662:Vasoconstrictor Agents; D014665:Vasodilator Agents; D010100:Oxygen