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.

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.

Decreased tyrosine hydroxylase activity in the adrenals of spontaneously hypertensive rats

Life Sciences ◽  
2005 ◽  
Vol 76 (25) ◽  
pp. 2953-2964 ◽  
Author(s):  
Eduardo Moura ◽  
Paulo M. Pinho Costa ◽  
Daniel Moura ◽  
Serafim Guimarães ◽  
Maria A. Vieira-Coelho
Keyword(s):  
Tyrosine Hydroxylase ◽  
Spontaneously Hypertensive Rats ◽  
Hypertensive Rats ◽  
Hydroxylase Activity ◽  
Spontaneously Hypertensive ◽  
Tyrosine Hydroxylase Activity

Adrenaline Neurons and PNMT Activity in the Brain and Spinal Cord of Genetically Hypertensive Rats and Rats with DOCA—salt Hypertension

1981 ◽  
Vol 61 (s7) ◽  
pp. 219s-221s ◽  
Author(s):  
J. P. Chalmers ◽  
P. R. C. Howe ◽  
Y. Wallmann ◽  
I. Tumuls
Keyword(s):  
Spinal Cord ◽  
Spontaneously Hypertensive Rat ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Hypertensive Rat ◽  
Genetically Hypertensive Rats ◽  
Salt Hypertension ◽  
Old Rats ◽  
Wistar Kyoto ◽  
Genetically Hypertensive

1. We have studied the number of phenylethanolamine-N-methyltransferase (PNMT)-containing nerve cells in the medulla and the activity of PNMT in the medulla, spinal cord and hypothalamus of the rat. 2. At 4 weeks of age there was an increase in the number of PNMT cells counted in the medulla of the spontaneously hypertensive rat (SHR; 21%, P < 0.01) and the stroke-prone spontaneously hypertensive rat (SHR-SP; 22%, P < 0.01) compared with the Wistar-Kyoto (WKY) control rat. 3. At 4 months of age there were no significant differences in the number of medullary PNMT cells in two normotensive strains (WKY and Fisher rats), two genetically hypertensive strains (SHR and SHR-SP) and in DOCA-salt hypertensive rats. 4. In four week old rats the activity of PNMT was increased by about 50% in the spinal cord and medulla of the SHR and SHR-SP compared with the WKY rats, and immunotitration experiments suggest that this is due to an increased concentration of enzyme. 5. At 4 months of age there were no increases in PNMT activity of either genetically hypertensive rats or DOCA-salt hypertensive rats.

Central cardiovascular effects of joining peptide in genetically hypertensive rats

1993 ◽  
Vol 265 (5) ◽  
pp. R1184-R1190
Author(s):  
T. Hamakubo ◽  
M. Yoshida ◽  
K. Nakajima ◽  
T. X. Watanabe ◽  
R. Mosqueda-Garcia ◽  
...  
Keyword(s):  
Specific Binding ◽  
Cardiovascular Effects ◽  
Cardiovascular Regulation ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Specific Binding Sites ◽  
Physiological Relevance ◽  
Wistar Kyoto ◽  
Intermediate Part ◽  
Genetically Hypertensive

Joining peptide (JP) is one of the major products of proopiomelanocortin (POMC). The biological function of this peptide has not been clarified despite its relative abundance in the pituitary and the hypothalamus. Recently we demonstrated that JP, which was isolated from bovine posterior pituitary, possesses Na pump inhibitor activity. The purpose of this study is to explore the physiological relevance of JP in cardiovascular regulation. For these investigations, we used the synthetic peptides bovine JP (bJP) and COOH-terminally amidated rat JP (rJP), since JP is known to have sequence variability among species. Intracisternal administration of both bJP and rJP in urethan-anesthetized rats evoked similar hypertensive and tachycardia effects. The effects of both peptides were markedly greater in the spontaneously hypertensive rats (SHR) compared with the normotensive Wistar Kyoto rats (WKY). Intravenous bolus injections of rJP at the same doses were without effect. Autoradiography, using 125I-labeled [0Tyr]-rJP as a ligand, revealed specific binding sites for rJP in the dorsal medulla in areas corresponding to the nucleus tractus solitarii (NTS) (extending from approximately 0.4 mm caudal to 1.8 mm rostral to the obex). Microinjections of rJP into the caudal part of the NTS of anesthetized SHR produced dose-related pressor and tachycardic responses. The pressor and tachycardic responses were also observed at the rostral part of the NTS, whereas the injections into the intermediate part of the NTS evoked depressor and bradycardic responses in SHR. These results suggest that at doses tested, the site of JP action resides in the central nervous system, and that JP is a potent neuropeptide in medullary sites known to be pivotal in central cardiovascular regulation. The effect of JP is especially prominent in the genetically hypertensive rat.

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.

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