scholarly journals Involvement of Cytochrome P450 Metabolites in the Vascular Action of Angiotensin II on the Afferent Arterioles.

2001 ◽  
Vol 24 (5) ◽  
pp. 551-557 ◽  
Author(s):  
Kentaro KOHAGURA ◽  
Shuji ARIMA ◽  
Yoshimi ENDO ◽  
Yoshiroh CHIBA ◽  
Osamu ITO ◽  
...  
Keyword(s):  
Cytochrome P450 ◽  
Angiotensin Ii ◽  
Afferent Arterioles

Angiotensin II effects on microvascular diameters of in vitro blood-perfused juxtamedullary nephrons

1986 ◽  
Vol 251 (4) ◽  
pp. F610-F618 ◽  
Author(s):  
P. K. Carmines ◽  
T. K. Morrison ◽  
L. G. Navar
Keyword(s):  
Angiotensin Ii ◽  
Constant Pressure ◽  
Ang Ii ◽  
Experimental Conditions ◽  
Vasoactive Hormones ◽  
Juxtamedullary Nephron ◽  
Single Nephron ◽  
Afferent Arterioles ◽  
Dose Dependent

The purpose of this study was to determine the specific renal microvascular segments that are functionally responsive to angiotensin II (ANG II) and other vasoactive hormones. Experiments were performed on juxtamedullary tissue from captopril-treated rats during perfusion with blood at a constant pressure of 110 mmHg. Epifluorescence videomicroscopy was utilized to measure diameters of arcuate and interlobular arteries (ART), mid- (MA) and late- (LA) afferent arterioles, and efferent arterioles (EA). Norepinephrine (700 nM) significantly decreased, and sodium nitroprusside (380 nM) increased, inside diameters of all segments. Topical application of ANG II (0.01 to 1 nM) induced significant reductions in diameters of all vessel segments: ART, 17.5 +/- 2.0%; MA, 19.6 +/- 2.5%; LA, 13.5 +/- 1.5%; and EA, 16.9 +/- 2.7%. The preglomerular response to ANG II was blocked by saralasin (10 microM) and, in most cases, was dose dependent; however, an initial hypersensitivity to low ANG II doses (30% decrease in diameter) was exhibited by 38% of the preglomerular vessels studied. Under these experimental conditions, single-nephron glomerular filtration rate decreased significantly in response to 0.01 nM ANG II exposure. These observations demonstrate that physiological concentrations of ANG II can elicit receptor-dependent and reversible vasoconstriction of the juxtamedullary nephron microvasculature at both pre- and postglomerular sites.

scholarly journals Cytochrome P450 1B1 Contributes to Renal Dysfunction and Damage Caused by Angiotensin II in Mice

Hypertension ◽  
2012 ◽  
Vol 59 (2) ◽  
pp. 348-354 ◽  
Author(s):  
Brett L. Jennings ◽  
Larry J. Anderson ◽  
Anne M. Estes ◽  
Fariborz A. Yaghini ◽  
Xiao R. Fang ◽  
...  
Keyword(s):  
Cytochrome P450 ◽  
Angiotensin Ii ◽  
Renal Dysfunction ◽  
Cytochrome P450 1B1

Direct evaluation of the microvascular actions of ANP in juxtamedullary nephrons

1988 ◽  
Vol 254 (3) ◽  
pp. F440-F444 ◽  
Author(s):  
P. J. Veldkamp ◽  
P. K. Carmines ◽  
E. W. Inscho ◽  
L. G. Navar
Keyword(s):  
Angiotensin Ii ◽  
Topical Administration ◽  
Normal Kidney ◽  
Arterial Diameter ◽  
Direct Evaluation ◽  
Juxtamedullary Nephron ◽  
Afferent Arterioles ◽  
Renal Vascular ◽  
Arteriolar Diameter

The renal vascular actions of atrial natriuretic peptide (ANP) remain incompletely understood. The purpose of this study is to evaluate the effects of ANP on microvascular structures of the normal kidney. The in vitro blood-perfused juxtamedullary nephron technique was utilized to allow visualization of arcuate arteries and afferent and efferent arterioles. Donor rats were pretreated with captopril to eliminate possible interactions between angiotensin II and atriopeptin III (AP III). The effects of topical administration of 3 nM AP III were determined by videometric analysis of vessel inside diameters. Under control conditions, arcuate arterial diameter averaged 83 +/- 14 microns (n = 7), afferent arteriolar diameter was 20 +/- 4 microns (n = 7), and efferent arteriolar diameter was 16 +/- 2 microns (n = 7). During superfusion with AP III, arcuate arteries and afferent arterioles dilated 73 +/- 9 and 23 +/- 5%, respectively. Both returned to their control values when AP III was removed from the superfusate. Further experiments on arcuate arteries (n = 5) revealed that 0.3 nM AP III also vasodilated these vessels (26 +/- 9%); however, no significant effect was elicited by 0.03 nM AP III. In contrast to the vasodilator influence of AP III on preglomerular vessels, efferent arteriolar diameter was not altered by AP III exposure. These observations reveal that AP III can induce selective preglomerular vasodilation involving arcuate arteries as well as afferent arterioles, while efferent arteriolar diameter is not perceptibly influenced.

Blockade of chloride channels by DIDS stimulates renin release and inhibits contraction of afferent arterioles

1996 ◽  
Vol 270 (5) ◽  
pp. F718-F727 ◽  
Author(s):  
B. L. Jensen ◽  
O. Skott
Keyword(s):  
Angiotensin Ii ◽  
Chloride Channels ◽  
Channel Blocker ◽  
Inhibitory Effect ◽  
Renin Release ◽  
Disulfonic Acid ◽  
Basal Diameter ◽  
Chloride Channel Blocker ◽  
Afferent Arterioles ◽  
Dose Dependent

Calcium-activated chloride channels have been proposed to control renin release from juxtaglomerular cells and to be involved in the excitation-contraction coupling of the renal afferent arteriole. The hypothesis was tested on renin release from rat glomeruli and in microperfused rabbit afferent arterioles with the chloride channel blocker 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS). Renin secretion was equally enhanced by omission of extracellular calcium and by addition of 0.5 mM DIDS. The inhibitory effect of calcium was blocked by DIDS. The stimulatory effects of low calcium [with or without ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid] and DIDS were not additive. In the absence of chloride, basal renin release was suppressed and the stimulatory effect of DIDS was abolished. The DIDS-induced enhancement of renin release was not dependent on bicarbonate. Norepinephrine (5 x 10(-7)-1 x 10(-6) M) and angiotensin II (1 x 10(-8)-10(-6) M) evoked reversible and dose-dependent contractions of microperfused rabbit afferent arterioles. DIDS (0.5 mM) did not affect the basal diameter of the arterioles but strongly inhibited the response to angiotensin II and attenuated the duration of the contractile response to norepinephrine. The results support the hypothesis that DIDS-sensitive calcium-activated chloride channels are involved in regulation of renin release and in the afferent arteriolar contraction after angiotensin II but do not play a pivotal role in the response to norepinephrine.

scholarly journals Effects of Angiotensin II on Isolated Rabbit Afferent Arterioles

1994 ◽  
Vol 66 (4) ◽  
pp. 457-464 ◽  
Author(s):  
Hiroyuki Yoshida ◽  
Toshiaki Tamaki ◽  
Yasuharu Aki ◽  
Shoji Kimura ◽  
Ikumasa Takenaka ◽  
...  
Keyword(s):  
Angiotensin Ii ◽  
Afferent Arterioles
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