Psychoneuroendocrine profile associated with hypertension or hyperactivity in spontaneously hypertensive rats

1993 ◽  
Vol 265 (6) ◽  
pp. R1304-R1310 ◽  
Author(s):  
N. Castanon ◽  
E. D. Hendley ◽  
X. M. Fan ◽  
P. Mormede
Keyword(s):  
Open Field ◽  
Spontaneously Hypertensive Rats ◽  
Inbred Strains ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Corticosterone Response ◽  
Wistar Kyoto Rat ◽  
Old Rats ◽  
Wistar Kyoto ◽  
Prolactin Response

The behavioral and neuroendocrine reactivity to a novel environment (open field) and the adrenocorticotropic hormone (ACTH)/corticosterone response to a corticotropin-releasing factor (CRF) challenge were measured in 2-mo-old rats from four inbred strains derived from the Wistar-Kyoto rat: spontaneously hypertensive rats (SHRs), hypertensive and behaviorally hyperactive to novelty; WKY, neither hypertensive nor hyperactive; WKHA, hyperactive but normotensive; and WKHT, only hypertensive. The ACTH response to CRF was much lower in SHRs than WKYs, this reduced reactivity being clearly associated with the hyperactivity trait, since it was present in the WKHA and absent in the WKHT strain. On the other hand, the ACTH/corticosterone response to a psychological stimulus (open field) could not clearly discriminate the four strains. The largest difference was found in the prolactin response. Post-open-field levels were much lower in the WKHA (27.11 +/- 4.69 ng/ml) than in the parent WKY strain (83.65 +/- 6.84 ng/ml), the hypertensive strains having intermediate levels (WKHT: 58.05 +/- 7.65 ng/ml; SHR: 64.13 +/- 7.19 ng/ml). Other differences were also found in the levels of aldosterone and renin activity. These results indicate that these strains are an excellent model to study neuroendocrine correlates of hypertension and hyperactivity, which are associated in the SHR strain and may be of interest for the study of the association between neuroendocrine and behavioral characteristics.

scholarly journals Perindoprilat Changes ANG (1-9) Production in Renal Arteries Isolated From Young Spontaneously Hypertensive Rats After ANG I Incubation

2016 ◽  
pp. 561-570
Author(s):  
P. P. WOŁKOW ◽  
B. BUJAK-GIŻYCKA ◽  
J. JAWIEŃ ◽  
R. OLSZANECKI ◽  
J. MADEJ ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Renal Artery ◽  
Spontaneously Hypertensive Rats ◽  
Renal Arteries ◽  
Ang Ii ◽  
Shr Rats ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Old Rats ◽  
Wistar Kyoto

We used mass spectrometry to quantitate production of angiotensinogen metabolites in renal artery of 3- and 7-month-old Wistar-Kyoto (WKY) and Spontaneously Hypertensive Rats (SHR). Tissue fragments were incubated for 15 min in oxygenated buffer, with added angiotensin I. Concentrations of angiotensins I (ANG I), II (ANG II), III (ANG III), IV (ANG IV), angiotensin (1-9) [ANG (1-9)], angiotensin (1-7) [ANG (1-7)], and angiotensin (1-5) [ANG (1-5)], excreted into the buffer during experiment, were measured using liquid chromatography-mass spectrometry (LC/MS) and expressed per mg of dry tissue. Effects of pretreatment with 10 μM perindoprilat on the production of ANG I metabolites were quantitated. Background production of any of ANG I metabolites differed neither between WKY and SHR rats nor between 3- and 7-month-old rats. Perindoprilat pretreatment of renal arteries resulted, as expected, in decrease of ANG II production. However, renal arteries of 7-month-old SHR rats were resistant to ACE inhibitor and did not change ANG II production in response to perindoprilat. In renal arteries, taken from 3-month-old rats, pretreated with perindoprilat, incubation with ANG I, resulted in the level of ANG (1-9) significantly higher in SHR than WKY rats. Our conclusion is that in SHR rats, sensitivity of renal artery ACE to perindoprilat inhibition changes with age.

Vasopressin and renin response to plasma volume loss in spontaneously hypertensive rats

1986 ◽  
Vol 250 (3) ◽  
pp. H443-H452 ◽  
Author(s):  
C. D. Sladek ◽  
M. L. Blair ◽  
Y. H. Chen ◽  
R. W. Rockhold
Keyword(s):  
Plasma Volume ◽  
Spontaneously Hypertensive Rats ◽  
Renin Angiotensin System ◽  
Hypertensive Rats ◽  
Angiotensin System ◽  
Spontaneously Hypertensive ◽  
Renin Angiotensin ◽  
Old Rats ◽  
Wistar Kyoto ◽  
Renin Content

Abnormalities in the vasopressin (VP) and renin-angiotensin systems have been described in spontaneously hypertensive rats (SHR). Responsiveness of these systems to a decrease in plasma volume was examined in the SHR at 6, 8, and 18 wk of age and compared with responses in age-matched normotensive Wistar and Wistar Kyoto rats (WKY). Trunk blood was collected 3 h after administration of 2 ml/100 g body wt of 0.9% saline, 15 or 30% polyethylene glycol (PEG), and in one group of conscious 8- and 18-wk-old rats, mean arterial pressure was monitored following PEG administration. Hematocrit and serum VP increased significantly in both strains at all ages following PEG. At 6 and 8 wk of age, the VP response to the PEG injection was significantly greater in SHR compared with WKY (P less than 0.005), but at 18 wk the response was comparable in the two strains. Serum renin activity (SRA) also increased in both strains receiving PEG at 6 and 8 wk of age, but the response was suppressed in the SHR relative to the WKY (P less than 0.001). At 18 wk of age, SRA increased in WKY, but the response was totally suppressed in SHR. Renal renin content in a separate group of rats was reduced in 19-wk-old SHR compared with WKY (P less than 0.001) but was not different in 5- and 8-wk-old rats. Thus there appears to be a hyperresponsiveness in the VP system in young SHRs that is not present in the renin-angiotensin system. The divergence in the responsiveness of the renin and VP systems and the attenuation of responsiveness in the VP system in 18-wk SHRs indicate a differential effect of the hypertensive process on the VP and renin systems in the SHR.

Excess oxygen delivery during muscle contractions in spontaneously hypertensive rats

1995 ◽  
Vol 78 (1) ◽  
pp. 101-111 ◽  
Author(s):  
J. M. Lash ◽  
H. G. Bohlen
Keyword(s):  
Blood Flow ◽  
Oxygen Saturation ◽  
Oxygen Delivery ◽  
Spontaneously Hypertensive Rats ◽  
Muscle Contractions ◽  
Hypertensive Rats ◽  
Hemoglobin Oxygen Saturation ◽  
Spontaneously Hypertensive ◽  
Tissue Po2 ◽  
Wistar Kyoto

These experiments determined whether a deficit in oxygen supply relative to demand could account for the sustained decrease in tissue PO2 observed during contractions of the spinotrapezius muscle in spontaneously hypertensive rats (SHR). Relative changes in blood flow were determined from measurements of vessel diameter and red blood cell velocity. Venular hemoglobin oxygen saturation measurements were performed by using in vivo spectrophotometric techniques. The relative dilation [times control (xCT)] of arteriolar vessels during contractions was as large or greater in SHR than in normotensive rats (Wistar-Kyoto), as were the increases in blood flow (2 Hz, 3.50 +/- 0.69 vs. 3.00 +/- 1.05 xCT; 4 Hz, 10.20 +/- 3.06 vs. 9.00 +/- 1.48 xCT; 8 Hz, 16.40 +/- 3.95 vs. 10.70 +/- 2.48 xCT). Venular hemoglobin oxygen saturation was lower in the resting muscle of SHR than of Wistar-Kyoto rats (31.0 +/= 3.0 vs. 43.0 +/- 1.9%) but was higher in SHR after 4- and 8-Hz contractions (4 Hz, 52.0 +/- 4.8 vs. 43.0 +/- 3.6%; 8 Hz, 51.0 +/- 4.6 vs. 41.0 +/- 3.6%). Therefore, an excess in oxygen delivery occurs relative to oxygen use during muscle contractions in SHR. The previous and current results can be reconciled by considering the possibility that oxygen exchange is limited in SHR by a decrease in anatomic or perfused capillary density, arteriovenular shunting of blood, or decreased transit time of red blood cells through exchange vessels.

scholarly journals Aging Additively Influences Insulin- and Insulin-Like Growth Factor-1-Mediated Endothelial Dysfunction and Antioxidant Deficiency in Spontaneously Hypertensive Rats

Biomedicines ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 676
Author(s):  
Kunanya Masodsai ◽  
Yi-Yuan Lin ◽  
Sih-Yin Lin ◽  
Chia-Ting Su ◽  
Shin-Da Lee ◽  
...  
Keyword(s):  
Growth Factor ◽  
Endothelial Dysfunction ◽  
Spontaneously Hypertensive Rats ◽  
No Production ◽  
Organ Bath ◽  
Insulin Like Growth Factor ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Nos Inhibitors ◽  
Wistar Kyoto

This study aimed to investigate the aging-related endothelial dysfunction mediated by insulin and insulin-like growth factor-1 (IGF-1) and antioxidant deficiency in hypertension. Male spontaneously hypertensive rats (SHRs) and age-matched normotensive Wistar–Kyoto rats (WKYs) were randomly divided into 24-week-old (younger) and 48-week-old (older) groups, respectively. The endothelial function was evaluated by the insulin- and IGF-1-mediated vasorelaxation of aortic rings via the organ bath system. Serum levels of nitric oxide (NO), malondialdehyde (MDA), catalase, and total antioxidant capacity (TAC) were examined. The insulin- and IGF-1-mediated vasorelaxation was significantly impaired in both 24- and 48-week-old SHRs compared with age-matched WKYs and was significantly worse in the 48-week-old SHR than the 24-week-old SHR. After pretreatments of phosphoinositide 3-kinase (PI3K) or NO synthase (NOS) inhibitors, the insulin- and IGF-1-mediated vasorelaxation became similar among four groups. The serum level of MDA was significantly increased, while the NO, catalase, and TAC were significantly reduced in the 48-week-old SHR compared with the 24-week-old SHR. This study demonstrated that the process of aging additively affected insulin- and IGF-1-mediated endothelial dysfunction in SHRs, which could be partly attributed to the reduced NO production and antioxidant deficiency.

Effects of dietary Ca2+ on erythrocyte Na+-transport systems in spontaneously hypertensive rats

1991 ◽  
Vol 81 (1) ◽  
pp. 107-112 ◽  
Author(s):  
K. Fujito ◽  
M. Yokomatsu ◽  
N. Ishiguro ◽  
H. Numahata ◽  
Y. Tomino ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Spontaneously Hypertensive Rats ◽  
Transport Systems ◽  
Hypertensive Rats ◽  
Na Transport ◽  
Spontaneously Hypertensive ◽  
Na Pump ◽  
Wistar Kyoto ◽  
Increased Activity ◽  
Regulation Of Blood Pressure

1. The purpose of this study was to determine the effect of dietary Ca2+ intake on blood pressure and erythrocyte Na+ transport in spontaneously hypertensive rats. 2. Spontaneously hypertensive rats and Wistar-Kyoto rats were fed diets with three different Ca2+ contents, 0.1% (low-Ca2+ diet), 0.6% (normal-Ca2+ diet) and 4.0% (high-Ca2+ diet), between 6 and 20 weeks of age. At 20 weeks of age, the levels of erythrocyte Na+ efflux, as well as Na+ and K+ contents in erythrocytes, were measured. 3. On the low-Ca2+ diet, spontaneously hypertensive rats showed an enhancement of hypertension. Conversely, on the high-Ca2+ diet, they showed an attenuation of the increase in blood pressure. Spontaneously hypertensive rats had a lower erythrocyte Na+ content and increased activity of the Na+ pump at higher levels of dietary Ca2+. Passive Na+ permeability and Na+-K+ co-transport were similar in spontaneously hypertensive rats on the low-, normal- and high-Ca2+ diets. There were no significant differences in blood pressure and in Na+ pump activity in WKY on the three different diets. 4. It is concluded that dietary Ca2+ might affect the regulation of blood pressure in spontaneously hypertensive rats by changing the activity of Na+ pump in the cell membrane.

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