Juxtamedullary afferent arteriolar responses to P1 and P2 purinergic stimulation

Edward W. Inscho, Pamela K Carmines, L. Gabriel Navar

Research output: Contribution to journalArticle

46 Citations (Scopus)

Abstract

We assessed the responsiveness of rat juxtamedullary afferent arterioles to purinergic stimulation using the in vitro blood-perfused juxtamedullary nephron technique combined with videomicroscopy to allow direct measurement of arteriolar inside diameter. To minimize the contribution of endogenously formed angiotensin II, all rats were pretreated with enalaprilat (2 mg i.v.) for 30 minutes before the right kidney was isolated and prepared for study. Renal perfusion pressure was set at 110 mm Hg and held constant. Afferent arteriolar diameter averaged 20.9±0.8 μm (n=41) under control conditions. Exposure to 1.0 μM 2-chloroadenosine induced a significant (11.1±3.2%) reduction in vessel diameter, whereas a 100 μM concentration induced an afferent vasodilation (7.6±1.5%; p<0.05). These data are consistent with the preferential stimulation of high affinity constrictor adenosine receptors (A1) at lower concentrations and activation of lower affinity vasodilator adenosine receptors (A2) at higher concentrations. In contrast, ATP elicited a significant afferent vasoconstriction of approximately 9.2%, 12.9%, and 10.0% at concentrations in the range of 1-100 μM (p<0.05). Treatment with ADP, at concentrations up to 100 μM, failed to alter vessel caliber significantly. Furthermore, the nonhydrolyzable ATP analogue α,β-methylene ATP produced a rapid and potent vasoconstriction, which mimicked the response to ATP. These data reveal the presence of both adenosine-sensitive P1 and ATP-sensitive P2 purinergic receptors on rat juxtamedullary afferent arterioles and demonstrate that ATP can induce afferent arteriolar vasoconstriction directly without first requiring hydrolysis to adenosine.

Original languageEnglish (US)
Pages (from-to)1033-1037
Number of pages5
JournalHypertension
Volume17
Issue number6 SUPPL. 2
StatePublished - Jan 1 1991

Fingerprint

Adenosine Triphosphate
Vasoconstriction
Arterioles
Adenosine
Adenosine A2 Receptors
2-Chloroadenosine
Enalaprilat
Purinergic P2 Receptors
Kidney
Adenosine A1 Receptors
Video Microscopy
Nephrons
Vasodilator Agents
Vasodilation
Angiotensin II
Adenosine Diphosphate
Hydrolysis
Perfusion
Pressure

Keywords

  • Arterioles
  • Purinergic receptors
  • Vasoconstriction

ASJC Scopus subject areas

  • Internal Medicine

Cite this

Juxtamedullary afferent arteriolar responses to P1 and P2 purinergic stimulation. / Inscho, Edward W.; Carmines, Pamela K; Navar, L. Gabriel.

In: Hypertension, Vol. 17, No. 6 SUPPL. 2, 01.01.1991, p. 1033-1037.

Research output: Contribution to journalArticle

Inscho, EW, Carmines, PK & Navar, LG 1991, 'Juxtamedullary afferent arteriolar responses to P1 and P2 purinergic stimulation', Hypertension, vol. 17, no. 6 SUPPL. 2, pp. 1033-1037.
Inscho, Edward W. ; Carmines, Pamela K ; Navar, L. Gabriel. / Juxtamedullary afferent arteriolar responses to P1 and P2 purinergic stimulation. In: Hypertension. 1991 ; Vol. 17, No. 6 SUPPL. 2. pp. 1033-1037.
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