Medullospinal sympathoexcitatory neurons in normotensive and spontaneously hypertensive rats

1986 ◽  
Vol 250 (5) ◽  
pp. R910-R917 ◽  
Author(s):  
M. K. Sun ◽  
P. G. Guyenet
Keyword(s):  
Spontaneously Hypertensive Rats ◽  
Discharge Rate ◽  
Maximal Activity ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Wky Rats ◽  
Significant Difference ◽  
Wistar Kyoto ◽  
The Relationship ◽  
Nerve Discharge

Aortic depressor nerve discharge (AND), lumbar sympathetic nerve discharge (SND), and single-unit activity of medullospinal pressure-sensitive neurons of nucleus paragigantocellularis lateralis (PGCL neurons) were recorded in halothane-anesthetized 16-wk-old spontaneously hypertensive rats (SHRs) and normotensive Wistar-Kyoto (WKY) rats. The relationship between these variables and mean arterial pressure (MAP) was investigated. The gain of baroreceptor afferents was not significantly different between the strains, but corner MAP (intersection between linear ascending portion of curve and noise) was 38 mmHg higher in SHRs. The relationship between SND and MAP and that between PGCL neuronal activity and MAP were both characterized by a plateau (maximal activity) at low MAP followed by a linear reduction reaching zero at a level called cutoff MAP. The theoretical intersection between the plateau and the linear decremental portion of these curves was defined as a corner MAP. Values of corner MAP determined at the three levels (AND, SND, PGCL) were identical in a given strain and reset by a common value in SHRs (38-40 mmHg). The gain of baroreceptor reflex measured at all three sites as the slope of the linear incremental (AND) or decremental (PGCL and sympathetic chain) portion of the activity-MAP relationship was the same in WKY rats and in SHRs. Cutoff MAP measured in PGCL was identical to that measured in peripheral sympathetic system for a given strain. There was no significant difference in maximal discharge rate of PGCL neurons nor in lumbar SND and no interstrain difference in the proportion of SND that was suppressible by arterial baroreceptor feedback.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibody-Sensitive Renin of Adrenal and Resistance Vessels is Markedly Elevated in Spontaneously Hypertensive Rats

1982 ◽  
Vol 63 (s8) ◽  
pp. 187s-189s ◽  
Author(s):  
Mitsuhide Naruse ◽  
Tadashi Inagami
Keyword(s):  
Spontaneously Hypertensive Rats ◽  
Renin Activity ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Wky Rats ◽  
Resistance Vessels ◽  
Significant Difference ◽  
Mesenteric Vessels ◽  
Wistar Kyoto

1. Three-week-old spontaneously hypertensive rats (SHR) showed markedly elevated specific renin activity in the adrenal and the mesenteric vessels compared with control Wistar-Kyoto (WKY)rats. 2. In 17-week-old SHR with established hypertension, adrenal renin remained markedly elevated over that of WKY rats, whereas no significant difference was observed in renin of the mesenteric vessels. 3. The specific renin activity of the aorta showed no significant difference compared with that of WKY rats at 3 or 17 weeks of age. 4. These results suggest possible involvement of adrenal and vascular renin in the pathogenesis of hypertension in SHR.

scholarly journals Sustained density of neuroendocrine cells with aging precedes development of prostatic hyperplasia in spontaneously hypertensive rats

BMC Urology ◽  
2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Yuki Kyoda ◽  
Koji Ichihara ◽  
Kohei Hashimoto ◽  
Ko Kobayashi ◽  
Fumimasa Fukuta ◽  
...  
Keyword(s):  
Spontaneously Hypertensive Rats ◽  
Prostatic Hyperplasia ◽  
Neuroendocrine Cells ◽  
Initial Growth ◽  
Hypertensive Rats ◽  
Initial Development ◽  
Spontaneously Hypertensive ◽  
Significant Difference ◽  
The Difference ◽  
Wistar Kyoto

Abstract Background Neuroendocrine (NE) cells may have an impact on the development and initial growth of benign prostatic hyperplasia (BPH) according to previous human studies. Methods To explore the relationship of NE cells and BPH development, we compared the density of NE cells and also prostatic weight in spontaneously hypertensive rats (SHR), which develop by aging, and Wistar-Kyoto rats (WKY) as control. The total weights of the epithelium and stroma in the ventral lobes of 8-, 12, 16-, 28- and 56-week-old SHR and WKY were calculated using Image J software. NE cells in the ventral prostatic ducts (VPd) were quantified using immunohistochemical staining for serotonin. Results Although there was no significant difference in the estimated total weight of the epithelium and stroma in the ventral lobes adjusted by body weight (ES weight) between the two groups at 8, 12 and 16 weeks of age, ES weight was significantly greater in the SHR group than in the WKT group at 28 and 56 weeks. The density of NE cells in the VPd decreased with aging in the WKY group, whereas it was sustained until 16 weeks and then decreased with aging in the SHR group. The difference in the density between the two groups was most marked at 16 weeks of age. Conclusion In the natural history of BPH, NE cells may play an important role in the initial development of BPH because sustained density of NE cells in the VPd precedes the development of prostatic hyperplasia.

scholarly journals Exercise changes regional vascular control by commissural NTS in spontaneously hypertensive rats

2010 ◽  
Vol 299 (1) ◽  
pp. R291-R297 ◽  
Author(s):  
Cristiana A. Ogihara ◽  
Gerhardus H. M. Schoorlemmer ◽  
Adriana C. Levada ◽  
Tania C. Pithon-Curi ◽  
Rui Curi ◽  
...  
Keyword(s):  
Arterial Pressure ◽  
Spontaneously Hypertensive Rats ◽  
The Body ◽  
Swimming Exercise ◽  
Exercise Session ◽  
Hypertensive Rats ◽  
Vascular Control ◽  
Spontaneously Hypertensive ◽  
Wky Rats ◽  
Wistar Kyoto

Inhibition of the commissural nucleus of the solitary tract (commNTS) induces a fall in sympathetic nerve activity and blood pressure in spontaneously hypertensive rats (SHR), which suggests that this subnucleus of the NTS is a source of sympathoexcitation. Exercise training reduces sympathetic activity and arterial pressure. The purpose of the present study was to investigate whether the swimming exercise can modify the regional vascular responses evoked by inhibition of the commNTS neurons in SHR and normotensive Wistar-Kyoto (WKY) rats. Exercise consisted of swimming, 1 h/day, 5 days/wk for 6 wks, with a load of 2% of the body weight. The day after the last exercise session, the rats were anesthetized with intravenous α-chloralose, tracheostomized, and artificially ventilated. The femoral artery was cannulated for mean arterial pressure (MAP) and heart rate recordings, and Doppler flow probes were placed around the lower abdominal aorta and superior mesenteric artery. Microinjection of 50 mM GABA into the commNTS caused similar reductions in MAP in swimming and sedentary SHR (−25 ± 6 and −30 ± 5 mmHg, respectively), but hindlimb vascular conductance increased twofold in exercised vs. sedentary SHR (54 ± 8 vs. 24 ± 5%). GABA into the commNTS caused smaller reductions in MAP in swimming and sedentary WKY rats (−20 ± 4 and −16 ± 2 mmHg). Hindlimb conductance increased fourfold in exercised vs. sedentary WKY rats (75 ± 2% vs. 19 ± 3%). Therefore, our data suggest that the swimming exercise induced changes in commNTS neurons, as shown by a greater enhancement of hindlimb vasodilatation in WKY vs. SHR rats in response to GABAergic inhibition of these neurons.

Methionine-enkephalin and vasopressin in SHR: effects of dehydration

1986 ◽  
Vol 250 (6) ◽  
pp. R1007-R1013
Author(s):  
K. Ota ◽  
L. Share ◽  
J. T. Crofton ◽  
D. P. Brooks
Keyword(s):  
Spontaneously Hypertensive Rats ◽  
Posterior Pituitary ◽  
Hypertensive Rats ◽  
Methionine Enkephalin ◽  
Spontaneously Hypertensive ◽  
Wky Rats ◽  
Plasma Vasopressin ◽  
Vasopressin Secretion ◽  
Wistar Kyoto ◽  
Shr And Wky Rats

Enkephalins are found in the posterior pituitary, can alter vasopressin secretion, and have greater pressor effects in spontaneously hypertensive rats (SHR) than in Wistar-Kyoto (WKY) rats. Measurement of the plasma methionine-enkephalin concentration (PMet-Enk) has provided equivocal results in humans and has not been reported in rats. We have developed a highly specific and sensitive Met-Enk radioimmunoassay and determined that Met-Enk circulates in rats but that PMet-Enk is no different between SHR and WKY rats (7.6 +/- 0.8 and 9.2 +/- 0.8 pg/ml, respectively). Water deprivation for 48 h increased the plasma vasopressin concentration (PADH) and 24-h urinary vasopressin excretion (UADHV) in SHR and WKY rats, but PMet-Enk was not altered. There were no differences in PADH and UADHV between SHR and WKY rats in either the euhydrated or dehydrated state. These results suggest that it is unlikely that circulating Met-Enk contributes importantly to the maintenance of hypertension in SHR. There was also no evidence for a greater secretion of vasopressin in SHR than in WKY rats, in contrast to previous reports.

scholarly journals Role of cholinergic receptors in adrenal catecholamine secretion in spontaneously hypertensive rats

1999 ◽  
Vol 277 (4) ◽  
pp. R1057-R1062 ◽  
Author(s):  
Takahiro Nagayama ◽  
Takayuki Matsumoto ◽  
Makoto Yoshida ◽  
Mizue Suzuki-Kusaba ◽  
Hiroaki Hisa ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Muscarinic Receptors ◽  
Nicotinic Receptors ◽  
Spontaneously Hypertensive Rats ◽  
Adrenal Glands ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Wky Rats ◽  
Wistar Kyoto

We investigated the role of nicotinic and muscarinic receptors in secretion of catecholamines induced by transmural electrical stimulation (ES) from isolated perfused adrenal glands of spontaneously hypertensive rats (SHRs) and normotensive Wistar-Kyoto (WKY) rats. ES (1–10 Hz) produced frequency-dependent increases in epinephrine (Epi) and norepinephrine (NE) output as measured in perfusate. The ES-induced increases in NE output, but not Epi output, were significantly greater in adrenal glands of SHRs than in those of WKY rats. Hexamethonium (10–100 μM) markedly inhibited the ES-induced increases in Epi and NE output from adrenal glands of SHRs and WKY rats. Atropine (0.3–3 μM) inhibited the ES-induced increases in Epi and NE output from adrenal glands of SHRs, but not from those of WKY rats. These results suggest that endogenous acetylcholine-induced secretion of adrenal catecholamines is predominantly mediated by nicotinic receptors in SHRs and WKY rats and that the contribution of muscarinic receptors may be different between these two strains.

scholarly journals Effect of a methionine-supplemented diet on the blood pressure of Wistar–Kyoto and spontaneously hypertensive rats

2003 ◽  
Vol 89 (4) ◽  
pp. 539-548 ◽  
Author(s):  
Sophie Robin ◽  
Véronique Maupoil ◽  
Frédérique Groubatch ◽  
Pascal Laurant ◽  
Alain Jacqueson ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Spontaneously Hypertensive Rats ◽  
Plasma Homocysteine ◽  
Shr Rats ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Wky Rats ◽  
Complex Interactions ◽  
Methionine Concentration ◽  
Wistar Kyoto

The objectives of the present work were to evaluate the effect of a methionine-supplemented diet as a model of hyperhomocysteinaemia on the systolic blood pressure (BP) and vasomotor functions of aortic rings in Wistar–Kyoto (WKY) and spontaneously hypertensive rats (SHR). WKY and SHR rats, randomised into four groups, were fed a normal semisynthetic diet or a methionine (8 g/kg)-supplemented diet for 10 weeks. Systolic BP was measured non-invasively. At the end of the experiment, plasma homocysteine, methionine, cysteine and glutathione levels were determined. Vasoconstriction and vasodilatation of aortic rings were measured. The methionine-supplemented diet induced a significant increase in plasma homocysteine and methionine concentration in both WKY and SHR rats, an increase in plasma cysteine concentrations in WKY rats and an increase in the glutathione concentration in SHR. The systolic BP of WKY rats fed the methionine-supplemented diet increased significantly (P<0·01), whereas systolic BP was reduced in SHR. An enhanced aortic responsiveness to noradrenaline and a decreased relaxation induced by acetylcholine and bradykinin were observed in the WKY rats fed the methionine-enriched diet. In SHR, the bradykinin-induced relaxation was reduced, but the sodium nitroprusside response was increased. In conclusion, a methionine-enriched diet induced a moderate hyperhomocysteinaemia and an elevated systolic BP in WKY rats that was consistent with the observed endothelial dysfunction. In SHR, discrepancies between the decreased systolic BP and the vascular alterations suggest more complex interactions of the methionine-enriched diet on the systolic BP. Further investigations are needed to understand the paradoxical effect of a methionine-rich diet on systolic BP.

Intra-Erythrocyte Sodium and (Na+,K+-Activated)-ATPase Concentration and Urinary Aldosterone Excretion in Spontaneously Hypertensive Rats

1981 ◽  
Vol 60 (2) ◽  
pp. 229-232 ◽  
Author(s):  
G. Berglund ◽  
L. Sigström ◽  
S. Lundin ◽  
B. E. Karlberg ◽  
H. Herlitz
Keyword(s):  
Spontaneously Hypertensive Rats ◽  
Sodium Concentration ◽  
Intracellular Sodium ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Wistar Kyoto Rats ◽  
Significant Difference ◽  
Intracellular Sodium Concentration ◽  
Erythrocyte Sodium ◽  
Wistar Kyoto

1. Intra-erythrocyte sodium, potassium, ATP and (Na+,K+-activated)-ATPase concentrations and urinary aldosterone excretion were compared in 3-month-old spontaneously hypertensive rats (n = 11) and normotensive Wistar-Kyoto control rats (n = 11). 2. Spontaneously hypertensive rats exhibited significantly higher intra-erythrocyte sodium concentration (5.5 ± 1.3 vs 4.0 ± 1.1 mmol/l of erythrocytes, P < 0.01). No significant difference was found in intra-erythrocyte potassium, ATP or (Na+,K+-activated)-ATPase concentration. 3. Mean urinary aldosterone excretion was significantly lower in spontaneously hypertensive rats (66.3 ± 6.5 pmol/24 h) than in Wistar-Kyoto rats (90.5 ± 10.6 pmol/24 h, P < 0.01). No significant relationship between urinary aldosterone and intra-erythrocyte sodium concentration was found in spontaneously hypertensive or Wistar-Kyoto rats or in the pooled group. 4. These results are thus consistent with previous findings of an increased intracellular sodium concentration in spontaneously hypertensive rats, but do not support the hypothesis that aldosterone is a dominant regulator of intracellular sodium concentration.

Clonidine fails to reduce pressor responsiveness of conscious spontaneously hypertensive rats to vasopressin

1986 ◽  
Vol 64 (3) ◽  
pp. 284-289 ◽  
Author(s):  
Sunil Datar ◽  
William H. Laverty ◽  
J. Robert McNeill
Keyword(s):  
Heart Rate ◽  
Arterial Pressure ◽  
Spontaneously Hypertensive Rats ◽  
Reflex Activity ◽  
Unexpected Finding ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Wky Rats ◽  
Wistar Kyoto ◽  
Shr And Wky Rats

Pressor responses and heart rate responses to intravenous injections (3.5–50.0 pmol/kg) of arginine vasopressin (AVP) were recorded in saline- and clonidine-treated spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto (WKY) rats. Clonidine (20 μg/kg, i. v.) caused a marked fall of arterial pressure in SHR but not in WKY rats so that, 20 min after the injection of the α2-adrenoceptor agonist, arterial pressure was similar in the two strains of rats. The curve expressing the relationship between the dose of AVP and the increase of arterial pressure for saline-treated SHR was positioned to the left of that for saline-treated WKY rats. This enhanced pressor responsiveness of SHR to AVP may have been related to impaired reflex activity since heart rate fell much less in SHR than in WKY rats for a given elevation in pressure. Pressure responses to AVP were augmented by clonidine in both SHR and WKY rats so that, similar to saline-treated rats, pressor responsiveness to the peptide was still greater in SHR. Heart rate responses to AVP were not altered significantly by clonidine. The results indicate that clonidine fails to enhance reflex activity and reduce pressor responsiveness of SHR to AVP. The increased pressor responsiveness of both SHR and WKY rats to AVP following clonidine was an unexpected finding and may be related to a peripheral interaction between α-adrenergic agonists and AVP.

scholarly journals Physiological and Behavioral Effects of d-threo-methylphenidate Hydrochloride in Male Wistar-Kyoto and Spontaneously Hypertensive Rats

2003 ◽  
Vol 2 (2) ◽  
Author(s):  
Jennifer Sayler ◽  
Linda Tennison ◽  
David Mitchell
Keyword(s):  
Working Memory ◽  
Spontaneously Hypertensive Rats ◽  
Spatial Working Memory ◽  
Membrane Lipids ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Glucose Levels ◽  
Wky Rats ◽  
Physiological Properties ◽  
Wistar Kyoto

Millions of children and adults worldwide are diagnosed with Attention-deficit hyperactivity disorder (ADHD) and yet its very existence, definition, and treatment are surrounded with discord and controversy. ADHD and its treatments are brought together through this investigation into the effects that drug therapy has on Wistar Kyoto rats (WKY) and a strain of Spontaneously Hypertensive rats (SHR) selectively inbred from WKY rats. The effects of the drug d-threo-methylphenidate hydrochloride (d-MPH - the d-isomer of the ADHD drug Ritalin) on spatial working memory abilities, overall growth rate, blood glucose levels, blood pH, and erythrocyte membrane lipids were examined in the two rat strains. Although all four physiological properties remained constant and normal over the course of the experiment, the spatial working memory abilities were inhibited in WKY rats receiving the drug. These results suggest that the d-isomer of this drug may have a significant impact on cognitive function in rats and possibly humans.

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