scholarly journals A primitive type of renin-expressing lymphocyte protects the organism against infections

2019 ◽  
Author(s):  
Brian C. Belyea ◽  
Araceli E. Santiago ◽  
Wilson A. Vasconez ◽  
Vidya K. Nagalakshmi ◽  
Theodore C. Mehalic ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Extracellular Fluid ◽  
Myoepithelial Cells ◽  
Endocrine Control ◽  
Unique Type ◽  
Electrolyte Homeostasis ◽  
Low Blood Pressure ◽  
And Control ◽  
Regulation Of Blood Pressure

ABSTRACTThe hormone renin plays a crucial role in the regulation of blood pressure and fluid-electrolyte homeostasis. Normally, renin is synthesized by juxtaglomerular (JG) cells, a specialized group of myoepithelial cells located near the entrance to the kidney glomeruli. In response to low blood pressure and/or a decrease in extracellular fluid volume (as it occurs during dehydration, hypotension, or septic shock) JG cells respond by releasing renin to the circulation to reestablish homeostasis. Interestingly, renin-expressing cells also exist outside of the kidney, where their function has remained a mystery. We discovered a unique type of renin-expressing B-1 lymphocytes that may have unrecognized roles in defending the organism against infections. These cells synthesize and release renin, entrap and phagocyte bacteria and control bacterial growth. The ability of renin-bearing lymphocytes to control infections – which is enhanced by the presence of renin – adds a novel, previously unsuspected dimension to the defense role of renin-expressing cells, linking the endocrine control of circulatory homeostasis with the immune control of infections to ensure survival.

scholarly journals A primitive type of renin-expressing lymphocyte protects the organism against infections

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Brian C. Belyea ◽  
Araceli E. Santiago ◽  
Wilson A. Vasconez ◽  
Vidya K. Nagalakshmi ◽  
Fang Xu ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Extracellular Fluid ◽  
Myoepithelial Cells ◽  
Endocrine Control ◽  
Unique Type ◽  
Electrolyte Homeostasis ◽  
Low Blood Pressure ◽  
And Control ◽  
Regulation Of Blood Pressure

AbstractThe hormone renin plays a crucial role in the regulation of blood pressure and fluid-electrolyte homeostasis. Normally, renin is synthesized by juxtaglomerular (JG) cells, a specialized group of myoepithelial cells located near the entrance to the kidney glomeruli. In response to low blood pressure and/or a decrease in extracellular fluid volume (as it occurs during dehydration, hypotension, or septic shock) JG cells respond by releasing renin to the circulation to reestablish homeostasis. Interestingly, renin-expressing cells also exist outside of the kidney, where their function has remained a mystery. We discovered a unique type of renin-expressing B-1 lymphocyte that may have unrecognized roles in defending the organism against infections. These cells synthesize renin, entrap and phagocyte bacteria and control bacterial growth. The ability of renin-bearing lymphocytes to control infections—which is enhanced by the presence of renin—adds a novel, previously unsuspected dimension to the defense role of renin-expressing cells, linking the endocrine control of circulatory homeostasis with the immune control of infections to ensure survival.

Influence of GABA in the nucleus of the solitary tract on blood pressure in baroreceptor-denervated rats

1997 ◽  
Vol 273 (5) ◽  
pp. R1657-R1662 ◽  
Author(s):  
Satoru Ito ◽  
Alan F. Sved
Keyword(s):  
Blood Pressure ◽  
Excitatory Input ◽  
Aminobutyric Acid ◽  
Solitary Tract ◽  
Direct Excitation ◽  
Gaba Antagonist ◽  
And Control ◽  
Regulation Of Blood Pressure ◽  
Intact Rats

We have previously reported that inhibition of the nucleus of the solitary tract (NTS) in chronically sinoaortic baroreceptor-denervated (SAD) rats has no effect on blood pressure in contrast to the marked increase in blood pressure it elicits in baroreceptor-intact rats. This could result either from a lack of tonic excitatory input to this region or from overriding inhibition of NTS neurons involved in the control of blood pressure. The present study aimed to distinguish between these two possibilities by examining the changes in blood pressure elicited by injection of bicuculline (Bic), a γ-aminobutyric acid (GABA) antagonist, into the NTS of SAD and control rats. In chloralose-anesthetized baroreceptor-intact rats or acutely SAD rats, injection of 10 pmol Bic into the NTS elicited minimal changes in blood pressure. In contrast, in chronic SAD rats injection of Bic into the NTS elicited a large decrease in blood pressure. The maximal decrease in blood pressure elicited by Bic in chronic SAD rats was equivalent to the maximal decrease in blood pressure that could be evoked by direct excitation of the NTS withl-glutamate. These results suggest that the lack of a tonic role of the NTS in the regulation of blood pressure in chronic SAD rats is a result of maximal GABA-mediated inhibition of relevant NTS neurons.

scholarly journals Regulation of Blood Pressure and Salt Homeostasis by Endothelin

2011 ◽  
Vol 91 (1) ◽  
pp. 1-77 ◽  
Author(s):  
Donald E. Kohan ◽  
Noreen F. Rossi ◽  
Edward W. Inscho ◽  
David M. Pollock
Keyword(s):  
Blood Pressure ◽  
Extracellular Fluid ◽  
Systemic Blood Pressure ◽  
Physiological Control ◽  
Water Excretion ◽  
Venous Capacitance ◽  
Physiological Regulation ◽  
Regulation Of Blood Pressure ◽  
Salt Homeostasis

Endothelin (ET) peptides and their receptors are intimately involved in the physiological control of systemic blood pressure and body Na homeostasis, exerting these effects through alterations in a host of circulating and local factors. Hormonal systems affected by ET include natriuretic peptides, aldosterone, catecholamines, and angiotensin. ET also directly regulates cardiac output, central and peripheral nervous system activity, renal Na and water excretion, systemic vascular resistance, and venous capacitance. ET regulation of these systems is often complex, sometimes involving opposing actions depending on which receptor isoform is activated, which cells are affected, and what other prevailing factors exist. A detailed understanding of this system is important; disordered regulation of the ET system is strongly associated with hypertension and dysregulated extracellular fluid volume homeostasis. In addition, ET receptor antagonists are being increasingly used for the treatment of a variety of diseases; while demonstrating benefit, these agents also have adverse effects on fluid retention that may substantially limit their clinical utility. This review provides a detailed analysis of how the ET system is involved in the control of blood pressure and Na homeostasis, focusing primarily on physiological regulation with some discussion of the role of the ET system in hypertension.

scholarly journals Nitric oxide synthase-mediated blood pressure regulation in obese melanocortin-4 receptor-deficient pregnant rats

2016 ◽  
Vol 311 (5) ◽  
pp. R851-R857 ◽  
Author(s):  
Frank T. Spradley ◽  
Jennifer M. Sasser ◽  
Jacqueline B. Musall ◽  
Jennifer C. Sullivan ◽  
Joey P. Granger
Keyword(s):  
Nitric Oxide ◽  
Blood Pressure ◽  
Mesenteric Arteries ◽  
Elevated Blood Pressure ◽  
Pressure Regulation ◽  
Elevated Blood ◽  
Pregnant Rats ◽  
Melanocortin 4 Receptor ◽  
Regulation Of Blood Pressure

Although obesity increases the risk for hypertension in pregnancy, the mechanisms responsible are unknown. Increased nitric oxide (NO) production results in vasodilation and reduced blood pressure during normal pregnancy in lean rats; however, the role of NO is less clear during obese pregnancies. We examined the impact of obesity on NO synthase (NOS)-mediated regulation of blood pressure during pregnancy by testing the hypothesis that NOS activity, expression, and regulation of vascular tone and blood pressure are reduced in obese pregnant rats. At gestational day 19, melanocortin-4 receptor (MC4R)-deficient obese rats (MC4R) had greater body weight and fat mass with elevated blood pressure and circulating sFlt-1 levels compared with MC4R pregnant rats. MC4R pregnant rats also had less circulating cGMP levels and reduced total NOS enzymatic activity and expression in mesenteric arteries. Despite decreased biochemical measures of NO/NOS in MC4R rats, NOS inhibition enhanced vasoconstriction only in mesenteric arteries from MC4R rats, suggesting greater NOS-mediated tone. To examine the role of NOS on blood pressure regulation in obese pregnant rats, MC4R and MC4R pregnant rats were administered the nonselective NOS inhibitor NG-nitro-l-arginine methyl ester (l-NAME, 100 mg/l) from gestational day 14 to 19 in drinking water. The degree by which l-NAME raised blood pressure was similar between obese and lean pregnant rats. Although MC4R obese pregnant rats had elevated blood pressure associated with reduced total NOS activity and expression, they had enhanced NOS-mediated attenuation of vasoconstriction, with no evidence of alterations in NOS-mediated regulation of blood pressure.

Nucleus tractus solitarius and control of blood pressure in chronic sinoaortic denervated rats

1992 ◽  
Vol 263 (2) ◽  
pp. R258-R266 ◽  
Author(s):  
A. M. Schreihofer ◽  
A. F. Sved
Keyword(s):  
Blood Pressure ◽  
Plasma Levels ◽  
Nucleus Tractus Solitarius ◽  
Inhibitory Influence ◽  
Baroreceptor Reflexes ◽  
Alpha Chloralose ◽  
And Control ◽  
Bilateral Destruction ◽  
Conscious Control

To determine the role of the nucleus tractus solitarius (NTS) in the tonic maintenance of arterial pressure (AP) following chronic baroreceptor denervation, the present study examined the effect of inhibition of the NTS on AP in chronic sinoaortic denervated (SAD) and control rats. One to two weeks after complete SAD (no residual arterial baroreceptor reflexes) mean AP was not significantly different from that of control rats. Bilateral microinjections of muscimol and lidocaine into the NTS markedly increased AP in alpha-chloralose-anesthetized control rats. However, microinjections of these neuroinhibitory drugs had no effect on AP in SAD rats. Similarly, 1 h after bilateral destruction of the NTS conscious control rats were hypertensive, while AP in SAD rats was not changed. Plasma levels of vasopressin (VP), which were also elevated in control rats 1 h after NTS lesions, were not significantly altered in SAD rats. These results demonstrate that inhibition of the NTS has no effect on AP or plasma levels of VP in chronic SAD rats. This suggests neither the NTS nor afferents to the NTS supply a tonic inhibitory influence on AP after chronic baroreceptor denervation.

Low blood pressure in vegetarians: the possible role of potassium

1983 ◽  
Vol 37 (5) ◽  
pp. 755-762 ◽  
Author(s):  
O Ophir ◽  
G Peer ◽  
J Gilad ◽  
M Blum ◽  
A Aviram
Keyword(s):  
Blood Pressure ◽  
Low Blood Pressure
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