Effects of Sinoaortic Baroreceptor Denervation on Blood Pressure and PNMT Activity in Medulla Oblongata and Spinal Cord of Normotensive and Genetically Hypertensive Rats

Several indirect evidences of alterations in the central catecholaminergic structures were obtained in genetically hypertensive rats. Because they could be of pathogenetic value, we measured, in the present work, the in vivo turnover (TO) of norepinephrine (NE) in brain areas of 5- and 22-wk-old genetically hypertensive (LH) rats of the Lyon strain, and their simultaneously selected normotensive (LN) and low blood pressure (LL) controls. Among the changes observed, the increased TO of NE in the A2 and A6 regions of 5-wk-old LH rats and its decrease in the posteroventral hypothalamic nucleus of 22-wk-old LH animals appeared likely to compensate for hypertension. On the contrary, the decreased TO of NE in the anterior hypothalamic nucleus observed at 5 wk and in the A6 and A1 areas at 22 wk of age in LH rats could participate in the development or the maintenance of hypertension. Above all, it was postulated that the increased TO of NE found in the A7 region of 5-wk-old LH rats could play a primary role in the pathogenesis of hypertension in the Lyon model.

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Renal eicosanoids and blood pressure in genetically hypertensive rats of the lyon strain

Journal of Biomedical Science ◽

10.1007/bf02253302 ◽

1994 ◽

Vol 1 (4) ◽

pp. 201-203 ◽

Cited By ~ 2

Author(s):

Jean Sassard ◽

Daniel Benzoni

Keyword(s):

Blood Pressure ◽

Hypertensive Rats ◽

Genetically Hypertensive Rats ◽

Genetically Hypertensive

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

Clinical Science ◽

10.1042/cs061219s ◽

1981 ◽

Vol 61 (s7) ◽

pp. 219s-221s ◽

Cited By ~ 4

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.

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Development of elevated blood pressure in young genetically hypertensive rats

Life Sciences ◽

10.1016/0024-3205(70)90025-1 ◽

1970 ◽

Vol 9 (5) ◽

pp. 247-250 ◽

Cited By ~ 17

Author(s):

D.R. Jones ◽

D.A. Dowd

Keyword(s):

Blood Pressure ◽

Elevated Blood Pressure ◽

Elevated Blood ◽

Hypertensive Rats ◽

Genetically Hypertensive Rats ◽

Genetically Hypertensive

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High blood pressure maintenance in transgenic mRen-2 vs. Lyon genetically hypertensive rats

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.1993.265.1.r180 ◽

1993 ◽

Vol 265 (1) ◽

pp. R180-R186 ◽

Cited By ~ 2

Author(s):

M. Lo ◽

I. A. Medeiros ◽

J. J. Mullins ◽

D. Ganten ◽

C. Barres ◽

...

Keyword(s):

Blood Pressure ◽

Renin Angiotensin System ◽

Renal Perfusion ◽

Sodium Reabsorption ◽

Sprague Dawley ◽

Hypertensive Rats ◽

Renal Handling ◽

Genetically Hypertensive Rats ◽

Pressure Natriuresis ◽

Genetically Hypertensive

The present work was aimed to assess the factors involved in the maintenance of hypertension in adult transgenic mRen-2 (TG) rats. Special attention was paid to the renal handling of sodium, the sympathetic, and the renin-angiotensin system (RAS) activity. TG rats were compared with age-matched Lyon genetically hypertensive rats (LH), as both are of Sprague-Dawley origin. Blood pressure (BP), heart rate, and renal sympathetic nerve activity (RSNA) were recorded in conscious freely moving animals. Kidneys were isolated and single-pass perfused at different pressure levels. It was observed that the peripheral sympathetic drive was identical in TG and LH rats as indicated by their similar 24-h urinary excretion of catecholamines and methoxylated metabolites, baseline RSNA and its control by the baroreflex, and hypotensive response to ganglion-blockade. On the contrary, TG rats differed from LH rats by a more rapid excretion of an oral isotonic sodium load, a greater hypotensive and natriuretic response to furosemide, and a more marked BP response to acute RAS blockade. The TG kidney responses to stepwise changes in renal perfusion pressure (RPP) differed from those of LH rats by significantly higher perfusate flow and glomerular filtration rate. However, the pressure natriuresis curve of TG kidneys did not differ from that of LH rats because of an elevated tubular sodium reabsorption rate. These results suggest that adult TG rats, compared with LH rats, exhibit a tendency toward sodium and water retention, which may explain that despite low renal and circulating renin levels, the RAS remains involved in the maintenance of high BP in that model.

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