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Kopp UC, Cicha MZ, Smith LA. Impaired Interaction Between Efferent and Afferent Renal Nerve Activity in SHR Involves Increased Activation of α
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-Adrenoceptors. Hypertension 2011; 57:640-7. [DOI: 10.1161/hypertensionaha.110.166595] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Ulla C. Kopp
- From the Departments of Internal Medicine (U.C.K., M.Z.C., L.A.S.) and Pharmacology (U.C.K.), University of Iowa Carver College of Medicine, and Department of Veterans Affairs Medical Center (U.C.K., M.Z.C., L.A.S.), Iowa City, IA
| | - Michael Z. Cicha
- From the Departments of Internal Medicine (U.C.K., M.Z.C., L.A.S.) and Pharmacology (U.C.K.), University of Iowa Carver College of Medicine, and Department of Veterans Affairs Medical Center (U.C.K., M.Z.C., L.A.S.), Iowa City, IA
| | - Lori A. Smith
- From the Departments of Internal Medicine (U.C.K., M.Z.C., L.A.S.) and Pharmacology (U.C.K.), University of Iowa Carver College of Medicine, and Department of Veterans Affairs Medical Center (U.C.K., M.Z.C., L.A.S.), Iowa City, IA
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Kopp UC, Cicha MZ. Impaired substance P release from renal sensory nerves in SHR involves a pertussis toxin-sensitive mechanism. Am J Physiol Regul Integr Comp Physiol 2004; 286:R326-33. [PMID: 14578115 DOI: 10.1152/ajpregu.00493.2003] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Stretching the renal pelvic wall activates renal mechanosensory nerves by a PGE2-mediated release of substance P via activation of the cAMP-PKA pathway. Renal pelvic ANG II modulates the responsiveness of renal sensory nerves by suppressing the PGE2-mediated activation of adenylyl cyclase via a pertussis toxin (PTX)-sensitive mechanism. In SHR, activation of renal mechanosensory nerves is impaired. This is due to suppressed release of substance P in response to increased pelvic pressure. The present study was performed to investigate whether the PGE2-mediated release of substance P was suppressed in SHR vs. WKY and, if so, whether the impaired PGE2-mediated release of substance P was due to ANG II activating a PTX-sensitive mechanism. In an isolated renal pelvic wall preparation, PGE2, 0.14 μM, increased substance P release from 9 ± 3 to 22 ± 3 pg/min ( P < 0.01) in Wistar-Kyoto rats (WKY), but had no effect in spontaneously hypertensive rats (SHR). A tenfold higher concentration of PGE2, 1.4 μM, was required to increase substance P release in SHR, from 7 ± 1 to 22 ± 3 pg/min ( P < 0.01). In SHR, treating renal pelvises with losartan enhanced the release of substance P produced by subthreshold concentration of PGE2, 0.3 μM, from 16 ± 2 to 26 ± 3 pg/min ( P < 0.01). Likewise, treating renal pelvises with PTX enhanced the PGE2-mediated release of substance P from 10 ± 1 to 33 ± 3 pg/min ( P < 0.01) in SHR. In WKY, neither losartan nor PTX had an effect on the release of substance P produced by subthreshold concentrations of PGE2, 0.03 μM. In conclusion, the impaired responsiveness of renal sensory nerves in SHR involves endogenous ANG II suppressing the PGE2-mediated release of substance P via a PTX-sensitive mechanism.
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Affiliation(s)
- Ulla C Kopp
- Dept. of Internal Medicine, VA Medical Center, Bldg. 3, Rm 226, Highway 6W, Iowa City, IA 52246, USA.
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