Hypertensive factor: calcium stimulatory activity obtained from different tissues and animal species

1988 ◽  
Vol 66 (10) ◽  
pp. 1278-1281 ◽  
Author(s):  
G. L. Wright ◽  
B. S. Huang ◽  
P. J. Johnson ◽  
W. D. McCumbee
Keyword(s):  
Blood Pressure ◽  
Rat Brain ◽  
Calcium Uptake ◽  
Contractile Response ◽  
Mammalian Species ◽  
Rat Tissues ◽  
Stimulatory Activity ◽  
Significant Stimulation ◽  
Stimulation Of

It was recently shown that a peptide (hypertensive factor, HF) isolated from erythrocyte hemolysates from spontaneously hypertensive rats induced a prolonged elevation of blood pressure in normotensive rats. In addition, the peptide produced a marked stimulation of the in vitro uptake of lanthanum-resistant calcium by the aortae and enhanced the contractile response of aortic rings to constrictor agents. The present report describes findings of calcium stimulatory activity, enhancement of contractile function, or pressor activity in extracts of homogenates from several tissues of the rat and from erythrocyte hemolysates of several mammalian species. Significant stimulation of calcium uptake in aortic rings was obtained with preparations from rat brain, liver, and kidney. The activity per weight of tissue was similar for brain and kidney (approximately 2 units/g), while liver exhibited somewhat higher concentrations (4 units/g). The diffusate of cardiac tissue did not significantly alter in vitro calcium uptake by aortae. The injection of the cardiac and liver diffusates into normotensive Wistar–Kyoto rats produced slight (10 Torr) (1 Torr = 133.3 Pa) and moderate (25 Torr) elevations of blood pressure, respectively. Finally, a peptide purified from homogenates of rat brain by the protocol developed for the purification of HF from erythrocytes was shown to significantly enhance the contractile response of aortic rings to K+ and norepinephrine. Diffusates of erythrocytes from the rat, rabbit, dog, and guinea pig each caused a significant stimulation of calcium uptake and contained approximately the same level of activity (500 units/L of whole blood). Diffusates prepared from outdated human erythrocytes had no significant effect on calcium uptake, whereas those of freshly drawn samples exhibited high levels of activity. Purification of the causal compound from several rat tissues and from erythrocytes of freshly drawn human blood indicated a peptide whose amino acid composition was qualitatively similar to that of the peptide isolated from erythrocytes of rats. The results suggest that a peptide or family of similar compounds may be present in a variety of tissues of the rat and occurs in the erythrocytes of several mammalian species. These peptides influence blood pressure, but we suggest that their principal role is in the regulation of cellular calcium metabolism.

Micturition reflexes in the in vitro neonatal rat brain stem-spinal cord-bladder preparation

1994 ◽  
Vol 266 (3) ◽  
pp. R658-R667 ◽  
Author(s):  
K. Sugaya ◽  
W. C. De Groat
Keyword(s):  
Spinal Cord ◽  
Electrical Stimulation ◽  
Brain Stem ◽  
Rat Brain ◽  
Bladder Wall ◽  
Spinal Reflex ◽  
Neonatal Rat ◽  
Evoked Contractions ◽  
Stimulation Of

An in vitro neonatal (1-7 day) rat brain stem-spinal cord-bladder (BSB) preparation was used to examine the central control of micturition. Isovolumetric bladder contractions occurred spontaneously or were induced by electrical stimulation of the ventrolateral brain stem, spinal cord, bladder wall (ES-BW), or by perineal tactile stimulation (PS). Transection of the spinal cord at the L1 segment increased the amplitude of ES-BW- and PS-evoked contractions, and subsequent removal of the spinal cord further increased spontaneous and ES-BW-evoked contractions but abolished PS-evoked contractions. Hexamethonium (1 mM), a ganglionic blocking agent, mimicked the effect of cord extirpation. Tetrodotoxin (1 microM) blocked ES-BW- and PS-evoked contractions but enhanced spontaneous contractions. Bicuculline methiodide (10-50 microM), a gamma-aminobutyric acid A receptor antagonist, increased the amplitude of spontaneous, ES-BW- and PS-evoked contractions. These results indicate that PS-evoked contractions are mediated by spinal reflex pathways, whereas spontaneous and ES-BW-evoked contractions that are elicited by peripheral mechanisms are subject to a tonic inhibition dependent on an efferent outflow from the spinal cord. PS-evoked micturition is also subject to inhibitory modulation arising from sites rostral to the lumbosacral spinal cord. Although electrical stimulation of bulbospinal excitatory pathways can initiate bladder contractions in the neonatal rat, these pathways do not appear to have an important role in controlling micturition during the first postnatal week.

In vitro effects of toxaphene on mitochondrial calcium ATPase and calcium uptake in selected rat tissues

Life Sciences ◽  
1985 ◽  
Vol 36 (5) ◽  
pp. 427-433 ◽  
Author(s):  
C.H. Trottman ◽  
K.S. Prasada Rao ◽  
W. Morrow ◽  
J.E. Uzodinma ◽  
D. Desaiah
Keyword(s):  
Calcium Uptake ◽  
Calcium Atpase ◽  
Mitochondrial Calcium ◽  
Rat Tissues ◽  
In Vitro Effects

An antihypertensive extract of erythrocytes: effects on 45Ca uptake and efflux

1986 ◽  
Vol 64 (4) ◽  
pp. 424-429
Author(s):  
G. L. Wright ◽  
G. O. Rankin ◽  
W. D. McCumbee
Keyword(s):  
Blood Pressure ◽  
Spontaneously Hypertensive Rats ◽  
Calcium Uptake ◽  
Slow Component ◽  
Present Report ◽  
Calcium Stores ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Washout Curves

The present report describes some aspects of the effects of a recently described antihypertensive extract of erythrocytes (AHF) on calcium uptake and efflux in rat aortae. AHF was found to be present in the erythrocytes of both spontaneously hypertensive rats and normotensive rats. Furthermore, AHF obtained from erythrocytes of SH rats was shown to be equally effective in suppressing lanthanum-resistant calcium uptake in aortae from hypertensive and normotensive rats. AHF treatment prior to incubation of aortae with 45Ca caused an apparent increase in the total 45Ca uptake. The analysis of calcium washout curves obtained for tissue in calcium-free or lanthanum-containing media indicated that AHF had no significant effect on the rate of calcium loss from the slow component of efflux, though this compartment tended to be reduced in size. This indicated that the increase in the 45Ca content of AHF-exposed aortae prior to rinsing was confined to the rapid component of efflux. The loss of calcium from the rapidly exchanging compartment was enhanced in either of the efflux media used. The results suggest that a principal action of AHF involves an increase in the lability and exchangeability of calcium stores. In addition to its effects in resting tissue, AHF abolished the increase in lanthanum-resistant calcium uptake induced in rat aortae by the addition of high K+ or norepinephrine to the incubation media. In a second part of the study, the effect of AHF on blood pressure and in vitro calcium uptake were compared with that of phosphatidylethanolamine (PEA), the probable identity of another endogenous antihypertensive (renin preinhibitor) compound earlier shown to share important functional similarities with AHF. The results reduce the likelihood that the two causal agents are identical. The AHF produced a significant (75 Torr, 1 Torr = 133.32 Pa) fall in the systolic blood pressure (SBP) of spontaneously hypertensive rats within 24 h following injection, whereas PEA had no effect on the SBP in this model. Both AHF and PEA reduced the resting in vitro uptake of "lanthanum-resistant" calcium in rat aortic segments. However, the AHF effect was significantly greater than PEA at each concentration studied.

Stimulation of Plasmin Activity by Aspirin

1991 ◽  
Vol 65 (04) ◽  
pp. 389-393 ◽  
Author(s):  
Ariel Milwidsky ◽  
Zvendana Finci-Yeheskel ◽  
Michael Mayer
Keyword(s):  
Binding Sites ◽  
Plasminogen Activators ◽  
Tissue Type ◽  
Amidolytic Activity ◽  
Antithrombotic Effect ◽  
Plasmin Activity ◽  
Human Control ◽  
Significant Stimulation ◽  
Stimulation Of

SummaryThis study demonstrates an enhancing effect of aspirin on the amidolytic activity of plasmin. The stimulation of plasmin by aspirin was concentration-dependent and was attained at aspirin concentrations above 2 × 10−4 M. Aspirin produced a small, reproducible and statistically significant stimulation of the chromogenic activity of plasmin upon H-D-Valyl-L-Leucyl-L-Lysine-p-nitroanilide (3-2251) or pyro-Glu-Gly-Arg-p-nitroanilide (S-2444). Kinetic analysis demonstrated a slight decrease in the affinity of plasmin for substrate 3-2251 in the presence of aspirin, reflected by a change of the Km from 3.2 × 10-4 M to 3.8 × 10-4 M, and an increase of the Vm. The reciprocal Lineweaver-Burk curve indicated an uncompetitive type of stimulation. The stimulatory effect of aspirin was abolished by the lysine analogue α-aminohexanoic acid (AHA) but not by the α-amino acid glutamic acid. The effect of AHA suggests a specific involvement of lysine binding sites (LBS) on plasmin in the interaction of the enzyme with aspirin. Tlansient acidification of plasmin abolished its response to aspirin, to AHA and to their combination. The addition of aspirin to diluted human control or pregnancy plasma in vitro stimulated the plasma-mediated cleavage of the chromogenic substrate3-2251. In contrast to its effect on plasmin, aspirin failed to change the activity of tissue-type or urokinasetype plasminogen activators. It is conceivable that in addition to the antithrombotic effect of aspirin ascribed to its interaction with the platelets, aspirin also directly stimulates plasmin activity.

Lipoate effect on carbohydrate and lipid metabolism and gastric H+ secretion

1975 ◽  
Vol 228 (3) ◽  
pp. 964-971 ◽  
Author(s):  
JB Harris ◽  
D Alonso ◽  
OH Park ◽  
D Cornfield ◽  
J Chacin
Keyword(s):  
Fatty Acids ◽  
Secretory Process ◽  
Rapid Decline ◽  
Beta Oxidation ◽  
Histamine Stimulation ◽  
Carbohydrate And Lipid Metabolism ◽  
Significant Stimulation ◽  
Rate Of Decline ◽  
Stimulation Of

Acid secretion (QH+) and oxygen consumption (Qo2) by frog gastric mucosae in vitro were sharply stimulated by lipoate. A rapid decline followed stimulation, subsequently falling below control values. Addition of only glucose or lactate had no effect on Qo2 or QH+. Pyruvate caused slight significant stimulation of Qo2. Any one of these compounds added to lipoate-treated mucosae increased the stimulatory effect of lipoate and markedly slowed the rate of decline subsequent to maximum stimulation. Various fatty acids had a moderate-to-high stimulatory effect on Qo2 and QH+. Lipoate added prior to the addition of fatty acids decreased the stimulatory effect of buryrate (minus 56%), decanoate (minus 87%), and palmitate (minus 60%). Propionate became an inhibitor in the presence of lipoate. Lipoate increased (plus 100%) the amount of glycogen oxidized and decreased (minus 69%) the amount of triglycerides oxidized. Lipoate-treated mucosae did not respond to histamine. Addition of glucose restored responsiveness. The results indicate that beta-oxidation of fatty acids plays a major role in the acid secretory process and is centrally involved in cyclic AMP and histamine stimulation of QH+.

scholarly journals cAMP-dependent inhibition is dominant in regulating superoxide production in the bone-resorbing osteoclasts

1998 ◽  
Vol 158 (3) ◽  
pp. 311-318 ◽  
Author(s):  
CE Berger ◽  
BR Horrocks ◽  
HK Datta
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Pertussis Toxin ◽  
Kinase C ◽  
Significant Stimulation ◽  
Dependent Inhibition ◽  
Dependent Protein ◽  
O2 Production ◽  
Stimulation Of

Calciotropic hormones such as parathyroid hormone (PTH) and calcitonin have been shown to have stimulatory and inhibitory effects respectively on superoxide anion (O2-) generation by osteoclasts, but the exact intracellular signalling mediating these pathways has not been investigated. In order to elucidate the intracellular pathways controlling O2- generation, we have carried out a systematic study of the effect of different agents on O2- production in osteoclasts cultured on bovine cortical bone. Dibutyryl cAMP and cholera toxin, while having no effect on the basal level of O2- production in bone-resorbing osteoclasts, were, however, found to completely block the stimulation of free radical production by PTH, pertussis toxin and ionomycin. The stimulation of O2- production was found to be independent of protein kinase C-dependent pathways since the presence of bisindolylmaleimide (GF109203X) (1 microM) did not block stimulation by PTH and pertussis toxin. Interestingly, while exposure to bisindolylmaleimide at this concentration did not have any effect on the basal level of O2- production, exposure to a higher concentration (10 microM), which is known to inhibit both protein kinase C and A, produced significant stimulation. These in vitro findings suggest that in the bone-resorbing cells, cAMP-dependent protein kinases prevent further stimulation of NADPH oxidase by agents such as PTH and pertussis toxin. The increase in cAMP has also been recently demonstrated to be associated with down-regulation of the oxidative burst in adherent neutrophils; and the findings reported here suggest a similar role for cAMP in O2- generation in osteoclasts cultured on bone.

Hypotensive properties of antibodies directed against an endogenous pressor peptide isolated from rat blood

1989 ◽  
Vol 67 (12) ◽  
pp. 1580-1585 ◽  
Author(s):  
Daniel G. Todd ◽  
William D. McCumbee ◽  
Gary L. Wright ◽  
William Kopp ◽  
Vernon E. Reichenbecher
Keyword(s):  
Blood Pressure ◽  
Calcium Uptake ◽  
Rapid Decline ◽  
Aortic Tissue ◽  
Blood Pressure Elevation ◽  
Antibody Preparation ◽  
Spontaneously Hypertensive ◽  
Immunoglobulin Preparations ◽  
Antibody Preparations ◽  
Stimulation Of

Hypertensive factor (HF), a compound isolated from the erythrocytes of rats and tentatively identified as a peptide, has been shown to influence tissue calcium metabolism and induce prolonged blood pressure elevation. In the present study, we investigated the biological properties of antibodies directed against this peptide. Partially purified antibody preparations significantly decreased HF stimulation of lanthanum-resistant calcium uptake in rat aortic tissue in vitro. Infusion of the antibody preparation into spontaneously hypertensive (SH) or normotensive Sprague–Dawley rats resulted in a rapid decline in mean blood pressure of 54 and 34 Torr (1 Torr = 133.332 Pa), respectively. In contrast, infusion of the serum immunoglobulin preparations from controls (unimmunized and ovalbumin-immunized rabbits) had no significant effect on the blood pressure of SH or normotensive rats. The systolic blood pressure of SH rats was reduced for at least 72 h following a single injection of the antibody preparations, whereas the blood pressure of normotensive rats had returned to normal levels within 24 h following antibody injection. The results indicate that the anti-HF antibody preparation antagonizes the stimulation of calcium uptake by the peptide and acutely lowers blood pressure in SH and normotensive rats.Key words: antibodies, blood pressure regulation, hypertensive factor, spontaneously hypertensive rat.

scholarly journals Electrical stimulation of cerebellar fastigial nucleus protects rat brain, in vitro, from staurosporine-induced apoptosis

2008 ◽  
Vol 79 (2) ◽  
pp. 328-338 ◽  
Author(s):  
Ping Zhou ◽  
Liping Qian ◽  
Sara B. Glickstein ◽  
Eugene V. Golanov ◽  
Virginia M. Pickel ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Rat Brain ◽  
Fastigial Nucleus ◽  
Induced Apoptosis ◽  
Stimulation Of

scholarly journals HAPTEN CARRIER RELATIONSHIPS IN THE DNP-PLL·FOREIGN ALBUMIN COMPLEX SYSTEM: INDUCTION OF TOLERANCE AND STIMULATION OF CELLS IN VITRO

1968 ◽  
Vol 127 (1) ◽  
pp. 43-53 ◽  
Author(s):  
Ira Green ◽  
William E. Paul ◽  
Baruj Benacerraf
Keyword(s):  
Lymph Node ◽  
Cell Cultures ◽  
Thymidine Incorporation ◽  
Lymph Node Cell ◽  
Simple Order ◽  
Significant Stimulation ◽  
Lymph Node Cells ◽  
Stimulate Cell Proliferation ◽  
Stimulation Of

Genetic nonresponder guinea pigs made tolerant to BSA and then immunized with DNP-PLL·BSA failed to make anti-DNP-PLL antibodies. Thus, tolerance to a carrier protein renders animals unresponsive to the hapten which it bears. The addition in vitro of DNP-PLL or DNP-GL to lymph node cell cultures derived from genetic responder animals immunized with these materials led to a significant stimulation of 3H-thymidine incorporation into DNA. However, the addition of DNP-PLL or DNP-GL to lymph node cell cultures from nonresponder animals immunized with these materials failed to produce any stimulation of DNA synthesis. Furthermore, the addition of DNP-PLL to lymph node cell cultures from nonresponder animals immunized with DNP-PLL·BSA or DNP-PLL·OVA also failed to stimulate cell proliferation in spite of the fact that the lymph node cells of these animals were producing anti-DNP-PLL antibodies. The above facts suggest that the function of the PLL gene product is to act at an early crucial step in the immune mechanism to form an antigen-inducer complex. The specificity of this early step may be of a simple order and different than that of the antibody which is later produced in the immune response.

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