Peripheral and Central Catecholaminergic Neurons in Genetic and Experimental Hypertension in Rats

1976 ◽  
Vol 51 (s3) ◽  
pp. 377s-380s ◽  
Author(s):  
H. Grobecker ◽  
J. M. Saavedra ◽  
M. F. Roizen ◽  
V. Weise ◽  
I. J. Kopin ◽  
...  
Keyword(s):  
Tyrosine Hydroxylase ◽  
Adrenal Glands ◽  
Experimental Hypertension ◽  
Hypertensive Rats ◽  
Hydroxylase Activity ◽  
Methyl Transferase ◽  
Spontaneously Hypertensive ◽  
Catecholaminergic Neurons ◽  
Wistar Kyoto ◽  
The Brain

1. Activity of peripheral and central catecholaminergic neurons was studied in spontaneously hypertensive rats (SHR) and deoxycorticosterone (DOCA)—salt hypertensive rats. 2. In young SHR (4 weeks) the plasma values of both noradrenaline and dopamine-β-hydroxylase activity were increased compared with those of normotensive rats of the Wistar/Kyoto strain. Total catecholamines (mostly adrenaline) were not significantly different. 3. In the adrenal glands of 2-weeks-old and 4-weeks-old SHR activities of tyrosine hydroxylase, dopamine-β-hydroxylase, phenylethanolamine-N-methyl transferase were decreased, compared to Wistar/Kyoto rats. 4. The adrenaline-forming enzyme was elevated in the A1 and A2 regions of the brain stem of 4-weeks-old SHR and in the A1 region of adult DOCA—salt hypertensive rats. 5. In the adrenal glands of adult DOCA—salt hypertensive rats tyrosine hydroxylase activity was increased. 6. These results implicate peripheral noradrenaline-containing neurons and central adrenaline-containing neurons in the development of genetic and experimental hypertension in rats.

Biosynthetic Enzyme Activities and Catecholamines in Adrenal Glands of Genetic and Experimental Hypertensive Rats

1982 ◽  
Vol 63 (s8) ◽  
pp. 113s-116s ◽  
Author(s):  
Horst Grobecker ◽  
Juan Saavedra ◽  
Virginia Weise
Keyword(s):  
Tyrosine Hydroxylase ◽  
Adrenal Glands ◽  
Experimental Hypertension ◽  
Hypertensive Rats ◽  
Hydroxylase Activity ◽  
Spontaneously Hypertensive ◽  
Tyrosine Hydroxylase Activity ◽  
Catecholamine Synthesizing Enzymes ◽  
Wistar Kyoto ◽  
Genetically Hypertensive

1. There was a significant decrease in the activity of tryosine hydroxylase, dopamine-β-hydroxylase and phenylethanolamine-N-methyltransferase in young spontaneously hypertensive rats (SHR) at the age of 2 and 4 weeks, compared with the activity in adrenals of the Wistar-Kyoto rat substrain. Tyrosine hydroxylase activity was not different in normotensive and hypertensive animals at 8 weeks of age but was increased in adult SHR. 2. Both dopamine-β-hydroxylase and phenylethanolamine-N-methyltransferase activities were still decreased at the age of 8 weeks in SHR, but were not significantly different from the controls at the age of 14 weeks. Blood pressures in SHR were slightly but significantly higher at 4 weeks of age and steadily rose during maturation. 3. In DOCA-saline hypertensive rats, tyrosine hydroxylase activity in adrenals was increased after only 1 week of treatment and remained increased after 2 and 4 weeks of treatment. Adrenal adrenaline was increased after 4 weeks of treatment, whereas dopamine-β-hydroxylase and phenylethanolamine-N-methyltransferase activities and noradrenaline levels were unchanged. 4. Our findings of increased tyrosine hydroxylase in adrenal glands of adult genetically hypertensive and chronic experimentally hypertensive rats indicate a sympathoadrenal activation during the established phase of the hypertension in both models. Whereas in DOCA-saline hypertensive rats catecholamine synthesis in adrenals parallels the development of high blood pressure, in genetically hypertensive rats the activity of the catecholamine-synthesizing enzymes is decreased early in development. These results suggest the existence of different mechanisms regulating the participation of adrenal catecholamines in both models of experimental hypertension.

Calmodulin levels in hypertensive rats

1985 ◽  
Vol 68 (4) ◽  
pp. 407-410 ◽  
Author(s):  
J. Higaki ◽  
T. Ogihara ◽  
Y. Kumahara ◽  
E. L. Bravo
Keyword(s):  
Intracellular Calcium ◽  
Spontaneously Hypertensive Rats ◽  
Hypertensive Rats ◽  
Deoxycorticosterone Acetate ◽  
Spontaneously Hypertensive ◽  
Calcium Dependent ◽  
Wistar Kyoto Rats ◽  
Regulatory Systems ◽  
Wistar Kyoto ◽  
The Brain

1. Intracellular calmodulin levels were measured by direct radioimmunoassay in spontaneously hypertensive rats (SHR) and Wistar—Kyoto rats (WKY). 2. Decreased calmodulin levels were demonstrated in the brain, heart, aorta and kidney of spontaneously hypertensive rats compared with those in Wistar—Kyoto rats. 3. Calmodulin levels in the brain were also decreased in deoxycorticosterone acetate (DOCA)-salt rats, but not changed significantly in the heart, aorta and kidney compared with those in Wistar—Kyoto rats. 4. These findings suggest that intracellular calcium-dependent regulatory systems are genetically disrupted in spontaneously hypertensive rats, but this is probably not an important factor in the development of hypertension.

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.

Vasopressin in brain of spontaneously hypertensive rats

1982 ◽  
Vol 242 (4) ◽  
pp. H496-H499 ◽  
Author(s):  
W. Rascher ◽  
R. E. Lang ◽  
T. Unger ◽  
D. Ganten ◽  
F. Gross
Keyword(s):  
Blood Pressure ◽  
Plasma Concentration ◽  
Brain Stem ◽  
Spontaneously Hypertensive Rats ◽  
Age Groups ◽  
Plasma Osmolality ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Wistar Kyoto ◽  
The Brain

In stroke-prone spontaneously hypertensive rats (SHRSP) and in normotensive Wistar-Kyoto rats (WKY), arginine vasopressin (AVP) was measured by means of a radioimmunoassay in the plasma, the pituitary gland, the hypothalamus, and the brain stem. In 6- and 14-wk-old SHRSP, the plasma concentration of AVP was lower than in age-matched WKY (P less than 0.01), whereas it was elevated at 28 wk of age (P less than 0.01). In the pituitary of 6-wk-old SHRSP, AVP was higher than in WKY (P less than 0.05), but no such difference was found in older rats. In the hypothalamus and the brain stem, AVP content was reduced in all age groups of SHRSP. Plasma osmolality was diminished in 28-wk-old SHRSP only (P less than 0.01), whereas hematocrit in all age groups was higher in SHRSP than in WKY. It is concluded that the secretion of AVP and possibly its synthesis in the hypothalamus are reduced in SHRSP. Whether the reduced AVP content in the brain stem is related to the sustained elevation of blood pressure has to be studied further.

scholarly journals Tyrosine hydroxylase immunoreactivity as indicator of sympathetic activity: simultaneous evaluation in different tissues of hypertensive rats

2011 ◽  
Vol 300 (2) ◽  
pp. R264-R271 ◽  
Author(s):  
Katia Burgi ◽  
Marina T. Cavalleri ◽  
Adilson S. Alves ◽  
Luiz R. G. Britto ◽  
Vagner R. Antunes ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Tyrosine Hydroxylase ◽  
Sympathetic Activity ◽  
High Performance ◽  
Hypertensive Rats ◽  
Regional Patterns ◽  
Spontaneously Hypertensive ◽  
Direct Recording ◽  
Wistar Kyoto ◽  
Different Tissues

Vasomotor control by the sympathetic nervous system presents substantial heterogeneity within different tissues, providing appropriate homeostatic responses to maintain basal/stimulated cardiovascular function both at normal and pathological conditions. The availability of a reproducible technique for simultaneous measurement of sympathetic drive to different tissues is of great interest to uncover regional patterns of sympathetic nerve activity (SNA). We propose the association of tyrosine hydroxylase immunoreactivity (THir) with image analysis to quantify norepinephrine (NE) content within nerve terminals in arteries/arterioles as a good index for regional sympathetic outflow. THir was measured in fixed arterioles of kidney, heart, and skeletal muscle of Wistar-Kyoto rats (WKY) and spontaneously hypertensive rats (SHR) (123 ± 2 and 181 ± 4 mmHg, 300 ± 8 and 352 ± 8 beats/min, respectively). There was a differential THir distribution in both groups: higher THir was observed in the kidney and skeletal muscle (∼3–4-fold vs. heart arterioles) of WKY; in SHR, THir was increased in the kidney and heart (2.4- and 5.3-fold vs. WKY, respectively) with no change in the skeletal muscle arterioles. Observed THir changes were confirmed by either: 1) determination of NE content (high-performance liquid chromatography) in fresh tissues (SHR vs. WKY): +34% and +17% in kidney and heart, respectively, with no change in the skeletal muscle; 2) direct recording of renal (RSNA) and lumbar SNA (LSNA) in anesthetized rats, showing increased RSNA but unchanged LSNA in SHR vs. WKY. THir in skeletal muscle arterioles, NE content in femoral artery, and LSNA were simultaneously reduced by exercise training in the WKY group. Results indicate that THir is a valuable technique to simultaneously evaluate regional patterns of sympathetic activity.

scholarly journals Effect of cytisine on some brain and hepatic biochemical parameters in spontaneously hypertensive rats

2010 ◽  
Vol 3 (1) ◽  
pp. 21-25 ◽  
Author(s):  
Rumyana Simeonova ◽  
Vessela Vitcheva ◽  
Mitka Mitcheva
Keyword(s):  
Biochemical Parameters ◽  
Spontaneously Hypertensive Rats ◽  
Vascular Diseases ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Alkaloid Cytisine ◽  
Wistar Kyoto ◽  
Cardio Vascular ◽  
Cytochrome P 450 ◽  
The Brain

Effect of cytisine on some brain and hepatic biochemical parameters in spontaneously hypertensive ratsTobacco smoking is a risk factor for variety of cardio-vascular diseases, such as hypertension, myocardial infarction, stroke and many others. It is of great importance for hypertensive patients to stop smoking. One of the medicines widely used for smoking cessation in Bulgaria is the original Bulgarian product Tabex®, which is developed on the basis of natural plant alkaloid cytisine. The aim of the following study was to ivestigate the effects of cytisine on some brain and hepatic biochemical parameters in spontaneously hypertensive rats (SHR), an widely used rodent model for human essential hypertension, and to compare the obtained results with their age-matched normotensive controls Wistar Kyoto (WKY). Multiple cytisine administration did not affect the activity of ethylmorphine-N-demethylase (EMND) and anylinehydroxylase (AH), as well as the quantity of cytochrome P 450, nor in WKY neither in SHR In the liver cytisine increased the MDA quantity both in SHR and in WKY, by 25% (p<0.05) and by 29% (p<0.05) respectively, while the GSH level was not significantly changed by the compound in both strains. In contrast, on the brain level, cytisine administration to SHR caused more prominent toxicity, resulted in GSH depletion and increased MDA quantity, while in WKY strain did not exert any toxicity. Cytisine did not significantly affect ALAT and ASAT activity in both strains. In conclusion, the results of our study suggest higher brain toxicity of cytisine in spontaneously hypertensive rats, that might be due to their pathophysiological characteristics.

The Ratio between Thickness of Media and Internal Radius in Cerebral, Mesenteric and Renal Arterial Vessels in Spontaneously Hypertensive Rats

1979 ◽  
Vol 57 (s5) ◽  
pp. 27s-29s ◽  
Author(s):  
C. Nordborg ◽  
B. B. Johansson
Keyword(s):  
Cerebral Arteries ◽  
Radius Ratio ◽  
Mesenteric Arteries ◽  
Hypertensive Rats ◽  
Vascular Abnormality ◽  
Spontaneously Hypertensive ◽  
Internal Radius ◽  
Vascular Beds ◽  
Wistar Kyoto ◽  
The Brain

1. Larger arterial vessels of 15-day-old spontaneously hypertensive (SH) rats showed significantly greater media/internal radius ratio than those of Wistar—Kyoto rats in the brain, kidney and mesentery. 2. Since larger cerebral and renal arteries of adult SH rats did not differ from controls the above results indicate the presence of a non-pressure-dependent vascular abnormality in young SH rats. 3. There were marked differences between the vascular beds of adult SH rats in the increase of media/radius ratio. Thus the changes were evident in all sizes of mesenteric arteries but only in the smallest cerebral arteries.

Upregulation of endothelin-1 binding in tissues of salt-loaded stroke-prone spontaneously hypertensive rats

2002 ◽  
Vol 80 (5) ◽  
pp. 470-474 ◽  
Author(s):  
Paula Savage ◽  
Arco Y Jeng
Keyword(s):  
Spontaneously Hypertensive Rats ◽  
Spontaneously Hypertensive Rat ◽  
Similar Proportion ◽  
Receptor Subtypes ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Endothelin 1 ◽  
Wistar Kyoto ◽  
Kidney Liver ◽  
The Brain

Upon maintained on a 1% NaCl drinking solution beginning at 7 weeks of age, the stroke-prone spontaneously hypertensive rat (SHRsp) developed severe hypertension and stroke; most died by 16 weeks. The mechanism by which these diseases evolve remains unclear. Endothelin-1 (ET-1) is a potent, peptidic vasoconstrictor and is implicated in the pathogenesis of various cardiovascular, renal, and central nervous system diseases. The purpose of the present study was to compare the binding of [125I]ET-1 to the brain, heart, kidney, liver, and spleen membrane preparations of 16-week-old SHRsp and age-matched normotensive Wistar–Kyoto rats (WKY). The KD values for [125I]ET-1 binding to the corresponding tissues of the two strains were not significantly different, except in the brain (SHRsp: 17 ± 1 pM; WKY: 24 ± 1 pM). In contrast, the Bmax values measured in the brain, heart, kidney, and liver of SHRsp were 1.5- to 2.1-fold greater than those of their WKY counterparts. Competition of [125I]ET-1 binding to the membrane preparations by the specific ETA receptor antagonist BQ-123 or the specific ETB receptor agonist sarafotoxin S6c revealed a similar proportion of ETA and ETB receptor subtypes in the corresponding tissues of the two rat strains. These results indicate that ET-1 binding is upregulated in SHRsp and suggest that ET-1 may play a pathophysiological role in this animal model of genetic hypertension.Key words: ETA receptor, ETB receptor, BQ-123, sarafotoxin 6C, stroke-prone spontaneously hypertensive rats.

Reduced Synthesis of [Arginine]Vasopressin in Spontaneously Hypertensive Rats

1982 ◽  
Vol 63 (s8) ◽  
pp. 117s-119s ◽  
Author(s):  
W. Rascher ◽  
R. E. Lang ◽  
B. Fink ◽  
D. Ganten ◽  
TH. Unger ◽  
...  
Keyword(s):  
Brain Stem ◽  
Arginine Vasopressin ◽  
Spontaneously Hypertensive Rats ◽  
Severe Dehydration ◽  
Hypertensive Rats ◽  
Brain Areas ◽  
Spontaneously Hypertensive ◽  
Wky Rats ◽  
Wistar Kyoto ◽  
The Brain

1. In 12 week-old stroke-prone spontaneously hypertensive (SPSH) rats and in normotensive Wistar-Kyoto (WKY) rats plasma concentration of [arginine]vasopressin (AVP) and the AVP content in various brain areas were measured by radioimmunoassay. 2. In hydrated SPSH rats plasma AVP was lower than in WKY rats. In the hypothalamus and in the brain stem, but not in the pituitary, the content of AVP was reduced. 3. After a dehydration period of 48 h plasma AVP rose similarly in both SPSH and WKY rats. However, in the pituitary the AVP content was significantly lower in SPSH than in WKY rats. In the hypothalamus and in the brain stem, AVP content was not significantly influenced by dehydration. 4. It is concluded that in the hydrated stage the secretion of AVP and its synthesis in the hypothalamus are reduced in SPSH rats. However, the SPSH rats still respond satisfactorily to the strong stimulus of severe dehydration.

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