Stimulation of steroid secretion by adrenocorticotropin injections and by arginine vasopressin infusions: no evidence for a direct stimulation of the human adrenal by arginine vasopressin

1991 ◽  
Vol 125 (4) ◽  
pp. 348-353 ◽  
Author(s):  
V. Bähr ◽  
J. Hensen ◽  
O. Hader ◽  
T. Bölke ◽  
W. Oelkers
Keyword(s):  
Arginine Vasopressin ◽  
Plasma Aldosterone ◽  
Regression Coefficients ◽  
Minor Importance ◽  
Cortisol Secretion ◽  
Plasma Acth ◽  
Direct Stimulation ◽  
Stimulatory Action ◽  
Stimulation Of

Abstract. Arginine vasopressin stimulates the secretion of adrenocorticotropin. A direct stimulatory effect of AVP on cortisol as well as aldosteron secretion has been postulated by several investigators. To study the possible role of a direct stimulatory action of AVP on the adrenal cortex, normal volunteers were treated with incremental injections of ACTH or with incremental infusions of AVP which raised plasma AVP levels to a maximum of 256±16 pmol/l. In both situations, a significant (p<0.001) linear correlation between plasma ACTH and plasma cortisol was observed. The regression coefficients were not different (p>0.5). Plasma aldosterone was stimulated by both treatments, but the weakly positive correlation between plasma ACTH and plasma aldosterone was not significant for either stimulus. Thus, in man, a direct stimulatory effect of AVP on cortisol secretion cannot be demonstrated. A direct effect of AVP on aldosterone cannot be definitely excluded, but is certainly of minor importance.

scholarly journals The Role of BMP Signaling in Osteoclast Regulation

2021 ◽  
Vol 9 (3) ◽  
pp. 24
Author(s):  
Brian Heubel ◽  
Anja Nohe
Keyword(s):  
Bone Formation ◽  
Bone Morphogenetic Proteins ◽  
Bone Diseases ◽  
Bmp Signaling ◽  
Bone Homeostasis ◽  
Direct Stimulation ◽  
Federal Drug Administration ◽  
Bmp Pathway ◽  
Stimulation Of

The osteogenic effects of Bone Morphogenetic Proteins (BMPs) were delineated in 1965 when Urist et al. showed that BMPs could induce ectopic bone formation. In subsequent decades, the effects of BMPs on bone formation and maintenance were established. BMPs induce proliferation in osteoprogenitor cells and increase mineralization activity in osteoblasts. The role of BMPs in bone homeostasis and repair led to the approval of BMP2 by the Federal Drug Administration (FDA) for anterior lumbar interbody fusion (ALIF) to increase the bone formation in the treated area. However, the use of BMP2 for treatment of degenerative bone diseases such as osteoporosis is still uncertain as patients treated with BMP2 results in the stimulation of not only osteoblast mineralization, but also osteoclast absorption, leading to early bone graft subsidence. The increase in absorption activity is the result of direct stimulation of osteoclasts by BMP2 working synergistically with the RANK signaling pathway. The dual effect of BMPs on bone resorption and mineralization highlights the essential role of BMP-signaling in bone homeostasis, making it a putative therapeutic target for diseases like osteoporosis. Before the BMP pathway can be utilized in the treatment of osteoporosis a better understanding of how BMP-signaling regulates osteoclasts must be established.

Replicating the Role of the Human Retina for a Cortical Visual Neuroprosthesis

2013 ◽  
pp. 1532-1551
Author(s):  
Samuel Romero ◽  
Christian Morillas ◽  
Antonio Martínez ◽  
Begoña del Pino ◽  
Francisco Pelayo ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Significant Degree ◽  
Research Field ◽  
Human Retina ◽  
Direct Stimulation ◽  
Biologically Inspired ◽  
Visual Inputs ◽  
Response Modeling ◽  
Stimulation Of

Neuroengineering is an emerging research field combining the latest findings from neuroscience with developments in a variety of engineering disciplines to create artificial devices, mainly for therapeutical purposes. In this chapter, an application of this field to the development of a visual neuroprosthesis for the blind is described. Electrical stimulation of the visual cortex in blind subjects elicits the perception of visual sensations called phosphenes, a finding that encourages the development of future electronic visual prostheses. However, direct stimulation of the visual cortex would miss a significant degree of image processing that is carried out by the retina. The authors describe a biologically-inspired retina-like processor designed to drive the implanted stimulator using visual inputs from one or two cameras. This includes dynamic response modeling with minimal latency. The outputs of the retina-like processor are comparable to those recorded in biological retinas that are exposed to the same stimuli and allow estimation of the original scene.

Stimulation of aldosterone biosynthesis by sodium sequestration: role of angiotensin II

1982 ◽  
Vol 243 (6) ◽  
pp. E450-E457
Author(s):  
J. Muller ◽  
E. G. Lund ◽  
L. Hofstetter ◽  
D. B. Brunner ◽  
P. Haldy
Keyword(s):  
Angiotensin Ii ◽  
Enzyme Inhibitor ◽  
Zona Glomerulosa ◽  
High Dose ◽  
Converting Enzyme ◽  
Bilateral Nephrectomy ◽  
Stimulatory Action ◽  
Sodium Sequestration ◽  
Stimulation Of

The role of angiotensin II in the stimulation of aldosterone biosynthesis by sodium sequestration in potassium-deficient rats was assessed by experiments involving 1-day angiotensin II infusion, converting enzyme inhibition, and bilateral nephrectomy. In intact rats, only an extremely high dose of exogenous angiotensin II imitated the stimulatory effects of polyethylene glycol-induced edema on the conversions of deoxycorticosterone and corticosterone to 18-hydroxycorticosterone and aldosterone. Treatment with the converting enzyme inhibitor captopril as well as bilateral nephrectomy blocked the aldosterone-stimulating action of edema. This inhibition was prevented by the simultaneous infusion of angiotensin II in captopril-treated rats but not in nephrectomized animals. According to these results, angiotensin II is an essential mediator in the stimulation of aldosterone biosynthesis by sodium sequestration. However, the role of the kidneys appears to be twofold. First, they act through the secretion of renin. In addition, a second yet unknown kidney factor is necessary for a full response of the zona glomerulosa to the stimulatory action of angiotensin II.

Stimulation of Na+/K+-ATPase activity by polyamines in the rat renal medullary cells of the thick ascending limb of Henle's loop

1990 ◽  
Vol 127 (3) ◽  
pp. 377-382 ◽  
Author(s):  
J. A. Charlton ◽  
P. H. Baylis
Keyword(s):  
Atpase Activity ◽  
Arginine Vasopressin ◽  
Thick Ascending Limb ◽  
Stimulus Response ◽  
Spermine Synthase ◽  
Medullary Thick Ascending Limb ◽  
Henle's Loop ◽  
Specific Inhibitors ◽  
Stimulation Of

ABSTRACT Previous studies have indicated that ornithine decarboxylase (ODC) may be involved in the stimulation of Na+/K+-ATPase activity by arginine vasopressin (AVP) in the rat renal medullary thick ascending limb of Henle's loop. The present study was aimed at establishing the role of the polyamines, the conversion products of ODC activity, in the stimulation of Na+/K+-ATPase by AVP. Using cytochemical methods, we have demonstrated an increase in Na+/K+-ATPase activity after stimulation with putrescine, spermidine and spermine (each 1 mmol/l) for 2·5,2 and 1·5 min respectively. The specific inhibitors of spermidine and spermine synthase, bis-cyclohexylammonium sulphate and N-alkylated-1,3-diaminopropane respectively, inhibited the stimulation of Na+/K+-ATPase by AVP, this inhibition being reversed by spermine. These findings suggest that polyamines are involved in the stimulus-response coupling of the hormone-mediated response. Journal of Endocrinology (1990) 127, 377–382

scholarly journals ARF6 stimulates clathrin/AP-2 recruitment to synaptic membranes by activating phosphatidylinositol phosphate kinase type Iγ

2003 ◽  
Vol 162 (1) ◽  
pp. 113-124 ◽  
Author(s):  
Michael Krauss ◽  
Masahiro Kinuta ◽  
Markus R. Wenk ◽  
Pietro De Camilli ◽  
Kohji Takei ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Synaptic Membranes ◽  
Direct Stimulation ◽  
Vesicle Membranes ◽  
Phosphatidylinositol Phosphate ◽  
Presynaptic Plasma Membrane ◽  
Phosphatidylinositol 4 ◽  
Adp Ribosylation Factor ◽  
Stimulation Of

Clathrin-mediated endocytosis of synaptic vesicle membranes involves the recruitment of clathrin and AP-2 adaptor complexes to the presynaptic plasma membrane. Phosphoinositides have been implicated in nucleating coat assembly by directly binding to several endocytotic proteins including AP-2 and AP180. Here, we show that the stimulatory effect of ATP and GTPγS on clathrin coat recruitment is mediated at least in part by increased levels of PIP2. We also provide evidence for a role of ADP-ribosylation factor 6 (ARF6) via direct stimulation of a synaptically enriched phosphatidylinositol 4-phosphate 5-kinase type Iγ (PIPKIγ), in this effect. These data suggest a model according to which activation of PIPKIγ by ARF6-GTP facilitates clathrin-coated pit assembly at the synapse.

Vagal regulation of gastric prostaglandin E2 release by central TRH in rats

1993 ◽  
Vol 264 (2) ◽  
pp. G231-G236 ◽  
Author(s):  
M. Yoneda ◽  
Y. Tache
Keyword(s):  
Prostaglandin E2 ◽  
Acid Output ◽  
Biologically Active ◽  
Central Action ◽  
Stimulatory Action ◽  
Pge2 Release ◽  
Cervical Vagotomy ◽  
The Brain ◽  
Stimulation Of

The central action of the stable thyrotropin-releasing hormone (TRH) analogue, RX 77368, to induce vagal release of gastric prostaglandin E2 (PGE2) was investigated in urethan-anesthetized rats. Intracisternal RX 77368 (1.5-1,000 ng) dose dependently increased gastric PGE2 levels measured for 3 h in the perfusate of dialysis fibers implanted into the corpus submucosa. RX 77368 injected intravenously (1,000 ng) had no effect. The stimulatory action of RX 77368 (1.5 ng) on gastric PGE2 release was blocked by indomethacin and bilateral cervical vagotomy. Omeprazole did not alter the PGE2 response to 3 ng of RX 77368 and reduced by 39% PGE2 release induced by the 1,000-ng dose. RX 77368 (1.5 ng) by itself did not influence acid secretion but increased acid output to 117 +/- 18 mumol/2 h in indomethacin-pretreated rats. Indomethacin also increased by 97% the acid response to the 3-ng dose of RX 77368, but the effect of a maximal effective dose of RX 77368 was not modified. These results indicate that RX 77368 acts in the brain to induce a vagal-dependent stimulation of gastric PGE2 secretion which is biologically active to reduce the acid response to submaximal doses of TRH analogue. These data suggest a possible role of medullary TRH in the central vagal regulation of gastric PGE2 release.

Replicating the Role of the Human Retina for a Cortical Visual Neuroprosthesis

2012 ◽  
pp. 346-365
Author(s):  
Samuel Romero ◽  
Christian Morillas ◽  
Antonio Martínez ◽  
Begoña del Pino ◽  
Francisco Pelayo ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Significant Degree ◽  
Research Field ◽  
Human Retina ◽  
Direct Stimulation ◽  
Biologically Inspired ◽  
Visual Inputs ◽  
Response Modeling ◽  
Stimulation Of

Neuroengineering is an emerging research field combining the latest findings from neuroscience with developments in a variety of engineering disciplines to create artificial devices, mainly for therapeutical purposes. In this chapter, an application of this field to the development of a visual neuroprosthesis for the blind is described. Electrical stimulation of the visual cortex in blind subjects elicits the perception of visual sensations called phosphenes, a finding that encourages the development of future electronic visual prostheses. However, direct stimulation of the visual cortex would miss a significant degree of image processing that is carried out by the retina. The authors describe a biologically-inspired retina-like processor designed to drive the implanted stimulator using visual inputs from one or two cameras. This includes dynamic response modeling with minimal latency. The outputs of the retina-like processor are comparable to those recorded in biological retinas that are exposed to the same stimuli and allow estimation of the original scene

scholarly journals Neuropeptide S Stimulates the Hypothalamo-Pituitary-Adrenal Axis and Inhibits Food Intake

Endocrinology ◽  
2006 ◽  
Vol 147 (7) ◽  
pp. 3510-3518 ◽  
Author(s):  
Kirsty L. Smith ◽  
Michael Patterson ◽  
Waljit S. Dhillo ◽  
Sejal R. Patel ◽  
Nina M. Semjonous ◽  
...  
Keyword(s):  
Food Intake ◽  
Hpa Axis ◽  
Paraventricular Nucleus ◽  
Arginine Vasopressin ◽  
Lateral Ventricle ◽  
Neuropeptide S ◽  
Plasma Acth ◽  
Vasopressin Release ◽  
Pituitary Adrenal Axis ◽  
Stimulation Of

Neuropeptide S (NPS) is a recently discovered peptide shown to be involved in the modulation of arousal and fear responses. It has also been shown that lateral ventricle administration of NPS causes a significant decrease in food intake. Neuropeptides involved in the modulation of arousal have been shown to be involved in the regulation of the hypothalamo-pituitary adrenal (HPA) axis and food intake. In this study, we have examined the effect of intracerebroventricular (ICV) administration of NPS on behavior, regulation of the HPA axis, and food intake. ICV NPS significantly increased plasma ACTH and corticosterone 10 and 40 min after injection, respectively. A single ICV injection of NPS caused a significant increase in rearing activity as well as ambulatory movement for up to 45 min after injection. We then studied the effect of paraventricular nucleus (PVN) administration of NPS on the regulation of the HPA axis, behavior, and food intake. There was a significant increase in plasma ACTH and corticosterone after a single NPS PVN injection. Incubation of hypothalamic explants with increasing concentrations of NPS caused a significant increase in CRH and arginine vasopressin release. In addition, PVN administration of NPS dose-dependently inhibited food intake in the first hour after injection, although no effect on food intake was seen after this time. PVN administration of NPS caused a significant increase in rearing activity. These data demonstrate a novel role for NPS in the stimulation of the HPA axis.

Role of calcium in osmotic and nonosmotic release of vasopressin from rat organ culture

1983 ◽  
Vol 244 (5) ◽  
pp. R703-R708
Author(s):  
S. Ishikawa ◽  
R. W. Schrier
Keyword(s):  
Angiotensin Ii ◽  
Organ Culture ◽  
Arginine Vasopressin ◽  
Ionophore A23187 ◽  
Ang Ii ◽  
Ca Uptake ◽  
High Concentrations ◽  
Cellular Ca ◽  
Stimulation Of

In the present study the role of calcium (Ca) in the stimulation of arginine vasopressin (AVP) release from the cultured rat hypothalamoneurohypophyseal complex (HNC) was examined in response to three different stimuli, 56 mM potassium chloride, an increase in medium osmolality from 290 to 310 mosmol/kg H2O, or 1 X 10(-6) M angiotensin II (ANG II). With all three stimuli AVP release from rat HNC explants was enhanced by increasing Ca concentration in the medium from 0 to 1.8 mM Ca. However, high concentrations of Ca (8 mM) inhibited the response of AVP release to either hyperosmolality or angiotensin II. Chemically dissimilar blockers of cellular Ca uptake, verapamil (5.2 X 10(-6) or 5.2 X 10(-5) M) or nifedipine (5.8 X 10(-6) or 5.8 X 10(-5) M), completely abolished AVP release from rat HNC explants in response to the three different stimuli in 1.8 mM Ca. In a normal concentration of medium Ca (1.8 mM) a Ca ionophore, A23187 (3.8 X 10(-5) M), significantly enhanced the osmotic and nonosmotic (ANG II-stimulated) release of AVP from rat HNC explants compared with controls without Ca ionophore. This effect of Ca ionophore to enhance AVP release was more evident in a lower Ca medium (0.9 mM Ca in the hyperosmolality study and 0.3 mM Ca in the ANG II study). These results therefore indicate that cellular Ca uptake is an important modulator of osmotic and nonosmotic AVP release from the intact rat hypothalamoneurohypophyseal system. The influence of extracellular Ca on the osmotic and nonosmotic release of AVP is also demonstrated.

Sign in / Sign up

Export Citation Format

Share Document