Biomaterial Database

Role of calcium ions in the pressure control of renin secretion from the kidneys. 1994

H Scholz, and M Hamann, and K H Götz, and A Kurtz

Institut für Physiologie I, Universität Regensburg, Germany.

In this study we examined the role of calcium ions in the control of renin release by the renal artery pressure. For this purpose renin secretion rates (RSR) were measured in isolated rat kidneys perfused at pressures of 140, 100, 80 and 40 mmHg (19, 13, 11, 5 kPa) with media containing either 1.5 mmol/l ("normal") or zero calcium concentrations (calcium-free perfusate with 0.5 mmol/l EGTA). At normal calcium the RSR was inversely related to the renal artery pressure, whereas calcium withdrawal resulted in an almost linear and proportional relationship between RSR and perfusion pressure. As a consequence, RSR at 140 mm Hg (19 kPa) with a calcium-free medium was similar to renin release at 40 mm Hg (5 kPa) with normal calcium. The nitric oxide (NO) donor sodium nitroprusside (1 mumol/l) stimulated RSR in a pressure-dependent fashion at a calcium concentration of 1.5 mmol/l. With a calcium-free perfusate, sodium nitroprusside did not restore the inverse pressure dependence of RSR seen with normal calcium but almost doubled the RSR across the whole pressure range. Whilst RSR was significantly reduced by angiotensin II (1 nmol/l) in the range between 40 mmHg and 140 mmHg (5-19 kPa) with normal calcium, withdrawal of extracellular calcium ions practically abolished the inhibitory action of angiotensin II. Since angiotensin II attenuated RSR especially at low renal perfusion pressure, our results indicate that renin release in this pressure range is still inhibitable by calcium mobilization in renal juxtaglomerular cells. Thus, the enhancement of renin secretion at lower pressures cannot be explained by a decreased sensitivity of renin release towards calcium ions.(ABSTRACT TRUNCATED AT 250 WORDS)

UI	MeSH Term	Description	Entries
D007606	Juxtaglomerular Apparatus	A complex of cells consisting of juxtaglomerular cells, extraglomerular mesangium lacis cells, the macula densa of the distal convoluted tubule, and granular epithelial peripolar cells. Juxtaglomerular cells are modified SMOOTH MUSCLE CELLS found in the walls of afferent glomerular arterioles and sometimes the efferent arterioles. Extraglomerular mesangium lacis cells are located in the angle between the afferent and efferent glomerular arterioles. Granular epithelial peripolar cells are located at the angle of reflection of the parietal to visceral angle of the renal corpuscle.	Apparatus, Juxtaglomerular
D007668	Kidney	Body organ that filters blood for the secretion of URINE and that regulates ion concentrations.	Kidneys
D008297	Male		Males
D009131	Muscle, Smooth, Vascular	The nonstriated involuntary muscle tissue of blood vessels.	Vascular Smooth Muscle,Muscle, Vascular Smooth,Muscles, Vascular Smooth,Smooth Muscle, Vascular,Smooth Muscles, Vascular,Vascular Smooth Muscles
D009599	Nitroprusside	A powerful vasodilator used in emergencies to lower blood pressure or to improve cardiac function. It is also an indicator for free sulfhydryl groups in proteins.	Nitroferricyanide,Sodium Nitroprusside,Cyanonitrosylferrate,Ketostix,Naniprus,Nipride,Nipruton,Nitriate,Nitropress,Nitroprussiat Fides,Nitroprusside, Disodium Salt,Nitroprusside, Disodium Salt, Dihydrate,Disodium Salt Nitroprusside,Nitroprusside, Sodium
D010477	Perfusion	Treatment process involving the injection of fluid into an organ or tissue.	Perfusions
D011311	Pressoreceptors	Receptors in the vascular system, particularly the aorta and carotid sinus, which are sensitive to stretch of the vessel walls.	Baroreceptors,Receptors, Stretch, Arterial,Receptors, Stretch, Vascular,Stretch Receptors, Arterial,Stretch Receptors, Vascular,Arterial Stretch Receptor,Arterial Stretch Receptors,Baroreceptor,Pressoreceptor,Receptor, Arterial Stretch,Receptor, Vascular Stretch,Receptors, Arterial Stretch,Receptors, Vascular Stretch,Stretch Receptor, Arterial,Stretch Receptor, Vascular,Vascular Stretch Receptor,Vascular Stretch Receptors
D012077	Renal Artery	A branch of the abdominal aorta which supplies the kidneys, adrenal glands and ureters.	Arteries, Renal,Artery, Renal,Renal Arteries
D012083	Renin	A highly specific (Leu-Leu) endopeptidase that generates ANGIOTENSIN I from its precursor ANGIOTENSINOGEN, leading to a cascade of reactions which elevate BLOOD PRESSURE and increase sodium retention by the kidney in the RENIN-ANGIOTENSIN SYSTEM. The enzyme was formerly listed as EC 3.4.99.19.	Angiotensin-Forming Enzyme,Angiotensinogenase,Big Renin,Cryorenin,Inactive Renin,Pre-Prorenin,Preprorenin,Prorenin,Angiotensin Forming Enzyme,Pre Prorenin,Renin, Big,Renin, Inactive
D001794	Blood Pressure	PRESSURE of the BLOOD on the ARTERIES and other BLOOD VESSELS.	Systolic Pressure,Diastolic Pressure,Pulse Pressure,Pressure, Blood,Pressure, Diastolic,Pressure, Pulse,Pressure, Systolic,Pressures, Systolic