Enhanced Phospholipase A2 Activity in Cultured Cardiomyocytes from Newborn Spontaneously Hypertensive Rat

1996 ◽  
Vol 90 (5) ◽  
pp. 403-407
Author(s):  
Elisabeth Millanvoye-Van Brussel ◽  
Marie-Aude Devynck
Keyword(s):  
Phospholipase A2 ◽  
Spontaneously Hypertensive Rat ◽  
Hypertensive Rats ◽  
Rat Cardiomyocytes ◽  
Spontaneously Hypertensive ◽  
Hypertensive Rat ◽  
Wistar Kyoto Rat ◽  
Wistar Kyoto ◽  
Phospholipase A2 Activity ◽  
Cultured Cardiomyocytes

1. Changes in membrane lipid composition and metabolism could participate in myocardial membrane dysfunction in essential or experimental hypertension. Phospholipid-bound fatty acid profile and metabolism are altered in cultured heart myocytes of newborn genetically hypertensive rats. The present study was designed to investigate the participation of phospholipase A2 in these modifications. 2. Phospholipase A2 activity of cultured cardiomyocytes of neonate spontaneously hypertensive rats and normotensive control Wistar—Kyoto rats was compared. The enzyme activity was measured using 2-[1-14C]arachidonyl-phosphatidylethanolamine as substrate. In both strains, Ca2+-dependent and independent phospholipase A2 activities were present. Only the Ca2+-dependent enzyme activity was altered in spontaneously hypertensive rat cardiomyocytes. With 0.2 mmol/l substrate and 5 mmol/l Ca2+, the phospholipase A2 activities were 79.0 ± 13.4 and 26.0 ± 3.6 nmol h−1 mg−1 of protein in spontaneously hypertensive and Wistar—Kyoto rat cardiomyocytes respectively (n = 10 in both cases, P = 0.001). The maximum velocity of the enzyme was three times higher in spontaneously hypertensive rat than in Wistar—Kyoto rat, without changes in the apparent affinity of the enzyme for its substrate. 3. The present results demonstrate an enhanced phospholipase A2 activity in cultured heart muscle cells of spontaneously hypertensive rats, which could be genetically determined.

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.

Hypothalamic angiotensin receptor subtypes in normotensive and hypertensive rats

1998 ◽  
Vol 275 (2) ◽  
pp. H703-H709 ◽  
Author(s):  
N. L. Han ◽  
M. K. Sim
Keyword(s):  
Angiotensin Ii ◽  
Spontaneously Hypertensive Rat ◽  
Renin Angiotensin System ◽  
Receptor Subtypes ◽  
Spontaneously Hypertensive ◽  
Hypertensive Rat ◽  
Angiotensin Iii ◽  
Displacement Experiments ◽  
Wistar Kyoto Rat ◽  
Wistar Kyoto

The binding of125I-labeled [Sar1,Ile8]angiotensin II to the hypothalamic membranes of the normotensive Wistar-Kyoto rat (WKY) and the spontaneously hypertensive rat (SHR) was studied. Displacement experiments with four centrally active angiotensins, losartan, and PD-123319 confirm the known existence of angiotensin AT1 and AT2 receptors in the rat hypothalamus. The values of the inhibitory constants for angiotensin II and PD-123319 in the SHR were significantly lower than the corresponding values in the WKY, indicating the possible existence of high-affinity hypothalamic AT1 and AT2 receptors for the two ligands in the SHR. The angiotensin AT1receptor was further separated into a 5′-guanylyl imidodiphosphate-sensitive and -nonsensitive subtype, indicating that one of the subtypes is G protein coupled. The SHR has significantly higher numbers of measurable AT1-receptor subtypes as well as AT2 receptor subtypes. The former data support the findings of other investigators showing that the hypothalamus of the SHR expressed more AT1A and AT1B mRNAs than that of the normotensive rat. Des-Asp1-angiotensin I, which is known to attenuate the central pressor action of angiotensin II and angiotensin III, acts on both the AT1 and AT2 receptors, although it has a higher affinity for the AT1receptors. The overall increase in the number of AT1 and AT2 receptors in the SHR is in line with the contention that the brain of the hypertensive rat, compared with that of the WKY, has a hyperactive renin-angiotensin system.

Effect of Sodium-Potassium-Dependent ATPase Inhibition on Noradrenaline-Activated Calcium Sensitivity of Mesenteric Resistance Vessels in Adult Spontaneously Hypertensive Rats

1980 ◽  
Vol 59 (s6) ◽  
pp. 203s-205s ◽  
Author(s):  
M. J. Mulvany ◽  
N. Nyborg ◽  
H. Nilsson
Keyword(s):  
Blood Vessels ◽  
Spontaneously Hypertensive Rat ◽  
Calcium Sensitivity ◽  
Sodium Potassium ◽  
Spontaneously Hypertensive ◽  
Rat Blood ◽  
Dependent Atpase ◽  
Hypertensive Rat ◽  
Wistar Kyoto Rat ◽  
Wistar Kyoto

1. We have investigated the noradrenaline-activated calcium sensitivity of 150 μm mesenteric resistance blood vessels from spontaneously hypertensive and control Wistar-Kyoto rats. 2. Under control conditions the spontaneously hypertensive rat blood vessels had a greater calcium sensitivity than the Wistar-Kyoto rat vessels. 3. In the presence of 1 mmol of ouabain/l, a treatment known to inhibit the sodium-potassium-dependent ATPase, the responses of the spontaneously hypertensive rat blood vessels were reduced more than those of the Wistar-Kyoto rat blood vessels, so that the responses of spontaneously hypertensive rat and Wistar-Kyoto rat blood vessels were then similar. 4. Similar results were obtained by removing external potassium, a procedure which should also inhibit the sodium-potassium-ATPase. 5. The results suggest that the greater noradrenaline-activated calcium sensitivity of spontaneously hypertensive rat blood vessels may be associated with an increased sodium-potassium-ATPase activity.

A morphological study of platelets from stroke-prone spontaneously hypertensive rat and Wistar Kyoto rat

1998 ◽  
Vol 5 (2) ◽  
pp. 119-124
Author(s):  
Masahiko Ikeda ◽  
James G White ◽  
Hideya Mizuno ◽  
Masaki Tabuchi ◽  
Takako Tomita
Keyword(s):  
Morphological Study ◽  
Spontaneously Hypertensive Rat ◽  
Spontaneously Hypertensive ◽  
Hypertensive Rat ◽  
Wistar Kyoto Rat ◽  
Wistar Kyoto
Sign in / Sign up

Export Citation Format

Share Document