Age variation in the increase of hypothalamic and brain stem contents of phenylethanolamine m-octopamine and p-octopamine in spontaneously hypertensive rats (SH kyoto)

Summary Phenylethanolamine, m=octopamine and p-octopamine contents were determined as a function of age in the hypothalamus and brain stem of spontaneously hypertensive rats and controls Wistar Kyoto. In hypothalamus, the content of the 3 amines was 2–4-fold greater for the SH rats. In the brain stem, the phenylethanolamine and p-octopamine contents were 2–3-fold greater in SH rats but 5–6-fold higher in the case of m-octopamine. The difference appears at 3 weeks and correlates the blood pressure with the increase of age. The significance of these findings is discussed.This work has been completed at the Tokyo University. The author is grateful to Professor Z. Tamura, Dr K. Imai and A. Ooshima as well as to the French Foreign Office and the Japanese Society for the Promotion of Sciences.     

Increased contents of phenylethanolamine, m-octopamine and p-octopamine in the hypothalamus and brain stem of spontanously hypertensive rats (S.H.R. Kyoto)]

Phenylethanolamine, p-octopamine and m-octopamine contents were determined in the hypothalamus and the brain stem of spontaneously hypertensive Rats (S.H.R. Kyto) and the corresponding controls (Wistar Kyoto). In three-week-old Rats, phenylethanolamine and p-octopamine are found to be present in S.H.R. hypothalamus and brain stem at concentrations twice as high as compared to Wistar Kyoto Rats. The amount of m-octopamine is 5-fold higher in the brain stem of S.H.R. Rats as compared to Wistar Kyoto Rats.     

Acid excretion in young and adult Wistar Kyoto and spontaneously hypertensive rats

Summary Wistar Kyoto rats (WKy), the most widely accepted control for SH rats, show an inability to excrete acid appropriately when compared to another normotensive strain, SD. Coupled with the fact that KWy also develops sodium-sensitive hypertension, this makes them a more complex control than realized. At very young ages (<10-week-old), neither SH nor WKy show any deficiency in acid excretion.Acknowledgments. Supported by AHA grant 76 1019 and NIH grant AM 15458. The excellent secretarial help of Susan Dreux and Betty Mendelson is acknowledged.     

Acid excretion in young and adult Wistar Kyoto and spontaneously hypertensive rats.

Wistar Kyoto rats (WKy), the most widely accepted control for SH rats, show an inability to excrete acid appropriately when compared to another normotensive strain, SD. Coupled with the fact than KWy also develops 'sodium-sensitive' hypertension, this makes them a more complex control than realized. At very young ages (less than 10-week-old), neither SH nor WKy show any deficiency in acid excretion.     

Decrease in [3H]ouabain binding sites in heart and brain from spontaneously hypertensive rats

Summary A decrease in the number of binding sites (B_max) for [³H]ouabain was observed in the heart (37%) and the brain (22%) of spontaneously hypertensive rats (SHR) when compared with age-matched control Wistar Kyoto rats. No variation was detected in the affinity constant (K_D).     

Blood pressure and impairment of endothelium-dependent relaxation in spontaneously hypertensive rats

Summary Correlation between hypertension and impairment of endothelium-dependent relaxation was demonstrated using aortae from certain strains of rats with various levels of spontaneous hypertension. It was also observed that the impairment of endothelium-dependent relaxation is the secondary change due to hypertension, and the level and duration of hypertension is the determinant factor of the impairment.     

Lower limit of cerebral autoregulation in normotensive and spontaneously hypertensive rats

Summary Cerebral autoregulation was examined in NTR and SHR. The lower blood pressure limit of autoregulation being 95 mm Hg in SHR was shifted upwards from 62 mm Hg in NTR.     

Adrenal enzymes of catecholamine biosynthesis and metabolism in spontaneously hypertensive rats

Zusammenfassung Es wird gezeigt, dass Dopa-Decarboxylase und Phenylethanolamin-N-methyl-transferase bei spontan hypertonischen Ratten im Vergleich zu normotonen Kontrollen leicht erhöht sind; hingegen wurde keine Veränderung der Catecholamin-abbauenden Enzyme festgestellt.     

Blood pressure and impairment of endothelium-dependent relaxation in spontaneously hypertensive rats

Correlation between hypertension and impairment of endothelium-dependent relaxation was demonstrated using aortae from certain strains of rats with various levels of spontaneous hypertension. It was also observed that the impairment of endothelium-dependent relaxation is the secondary change due to hypertension, and the level and duration of hypertension is the determinant factor of the impairment.     

Structural basis for resetting of baroreceptor regulation in spontaneously hypertensive rats (SHR)

Zusammenfassung Nachweis, dass in Ratten mit genetischem Hochdruck und normalem Herzrhythmus Verdickungen des Endotheliums im Karotissinus und im Aortabogen beobachtet werden. Eine Hypertrophie der Gefässmuskulatur war nachweisbar, was zu einer Abschwächung des Drucksignals zur Stelle der Pressorezeptoren führte. Diese dürften teilweise verantwortlich sein für die Verschiebung der Pressorezeptor-Steuerung bei genetisch hypertensiven Ratten.

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This study is partly supported by I.W.O.N.L.     

Features of intracellular calcium distribution in the adipose tissue of spontaneously hypertensive rats (SHR)

The in vitro study of the kinetics of 45Ca efflux from adipose tissue of rats reveals 3 pools of exchangeable calcium. Calcium content in the intracellular pools of adipose tissue of spontaneously hypertensive rats is increased as compared to that in normotensive controls.     

Features on intracellular calcium distribution in the adipose tissue of spontaneously hypertensive rats (SHR)

Summar The in vitro study of the kinetics of⁴⁵Ca effux from adipose tissue of rats reveale 3 pools of exchangeable calcium. Calcium content in the intracellular pools of adipose tissue of spontaneously hypertensive rats is increased as compared to that in normotensive controls.     

Isoprotenerol induction of pineal serotonin N-acetyltransferase in normotensive and spontaneously hypertensive rats

Zusammenfassung Verabreichung von Isoprotenerol, eines -adrenergen Agonisten, induziert einen signifikant höheren Anstieg der Aktivität der Serotonin-N-Acetyltransferase in der Epiphyse von spontan hypertensiven, im Vergleich mit normotensiven, Rattenmännchen. Derselbe Unterschied wurde auch bei Weibchen beobachtet, jedoch liegen die Aktivitätswerte bei spontan hypertensiven Männchen allgemein höher. Die durch Isoprotenerol erhöhte Induktion der Serotonin-N-Acetyltransferase erzeugt hinsichtlich der Catecholamine in den Pinealozyten von spontan hypertensiven Ratten eine veränderte Reaktivität der Achse -Rezeptor-Adenylzyklasesystem-Serotonin-N-Acetyl transferase.     

Central influence of vasopressin on baroreceptor reflex in normotensive rats and its lack in spontaneously hypertensive rats (SHR)

Summary In normotensive Wistar rats intracerebroventricular (i.c.v.) injection of 30 mU of lysine⁸-vasopressin enhances significantly the cardiovagal reflex bradycardia induced by a blood pressure rise. This effect is absent in spontaneously hypertensive rats (SHR) of the Okamoto strain.     

Quantitative immunofluorescence of tyrosine hydroxylase in the adrenal medulla of spontaneously hypertensive rats

The amount of tyrosine hydroxylase protein in the adrenal medulla, which was estimated by a quantitative immunofluorescence method, was higher in spontaneously hypertensive rats than in normotensive control Wistar-Kyoto rats at 4 and 16 weeks of age before and after the development of hypertension.     

Quantitative immunofluorescence of tyrosine hydroxylase in the adrenal medulla of spontaneously hypertensive rats

Summary The amount of tyrosine hydroxylase protein in the adrenal medulla, which was estimated by a quantitative immunofluorescence method, was higher in spontaneously hypertensive rats than in normotensive control Wistar-Kyoto rats at 4 and 16 weeks of age before and after the development of hypertension.This study was supported by grants from the Ministry of Education, Science and Culture, Japan (No. 59570018). Reprint requests to I.N., Department of Anatomy, School of Medicine, Fujita-Gakuen Health University, Toyoake, Aichi 470-11 (Japan).