Catecholamine Release Modulation by Adenosine Through A2a Receptors in Mouse Chromaffin Cells in Culture
Magda M. SantanaJoana Rosmaninho‐SalgadoManuella P. KasterVera CortezRodrigo A. CunhaCláudia Cavadas
0
Citation
2
Reference
10
Related Paper
In the last three decades, numerous articles on plasma catecholamine concentrations in various settings have been published in the medical literature. Despite this abundance of information, no summary article has analyzed the species variations in circulating catecholamine concentrations. In this paper, the plasma catecholamine responses to various stresses in 31 animal groups have been compiled from 200 publications (with > 5000 animal subjects). Primitive cartilaginous fish such as the shark and the lamprey have the highest reported basal plasma catecholamine concentrations. Birds, mammals, and teleost fish have the lowest concentrations. The lower circulating catecholamine concentrations parallel anatomical changes in the development of the adrenal medulla and the development of the nervous system. Decapitation, hypoxia, hemorrhage, and hypothermia are the experimental conditions associated with the greatest stress-induced changes in plasma catecholamine concentrations. The differences in experimental design are tabulated to afford the reader an opportunity to compare catecholamine levels among species. The table provides a detailed guide to normal concentrations and normal responses in 31 species. This report gives a dynamic overview of catecholamine concentrations in human and animal physiology and may be particularly helpful to investigators involved in catecholamine research.
Cite
Citations (57)
The relative concentrations of catecholamine in the nervous system of the entomophilic nematode Romanomermis culicivorax were measured under different experimental conditions by a glyoxylic acid-induced fluorescence procedure. A greater concentration of catecholamine was recorded in the nervous system of adult males and females than in postparasitic juveniles. A higher concentration of catecholamine occurred in adults maintained in physical contact with the opposite sex than in those maintained in isolation. Adult males maintained with females in the same aqueous medium but physically separated by a barrier displayed a greater concentration of catecholamine in their nervous systems than did males maintained in isolation, but the catecholamine fluorescence intensity of such males was less than in males allowed physical contact with females. In adult males, the fluorescence intensity of catecholamine declined progressively during and after copulation. In adult females, the intensity of catecholamine remained constant before, during, and after copulation. Catecholamine(s) may play a role in regulating copulatory behavior, egg production, or oviposition.
Sympathetic nervous system
Cite
Citations (5)
1. Four studies were designed to test the hypothesis that platelet catecholamine levels may provide a stable index of circulating plasma catecholamine concentrations, and that these are unaffected by acute elevations of plasma levels with physical and psychological stress. 2. To assess the biological variability within individuals, ten subjects were sampled on five occasions over 8–30 h. The intra-individual coefficients of variation for plasma and platelet noradrenaline levels were 193 +10% and 9.5 +4.2%, respectively, and for plasma and platelet adrenaline levels 48.3 +22% and 25.3 +8.4%, respectively. 3. Three other studies investigating the response to physical and psychological stress were performed. In the first study, plasma and platelet catecholamine levels were studied in 12 healthy subjects before and after bicycle ergometry. Plasma catecholamine concentrations increased [noradrenaline by +346 + 323% (P = 0.002) and adrenaline by +314 + 352% (P -0.003)], whereas platelet concentrations showed little change [noradrenaline +4+18% (P = 0.94) and adrenaline +38+ 116% (P = 0.67)]. 4. In the study, catecholamine concentrations were measured in eight subjects after hand immersion in iced water. Plasma noradrenaline concentrations increased significantly (+58 +19%, P = 0.001), but no significant change was found in plasma adrenaline concentrations (+8+44%, P = 0.48). Platelet catecholamine concentrations showed no significant change (noradrenaline +15 +15%, P = 0.052, and adrenaline 19 +82%, P = 0.84). 5. In the third study, catecholamine concentrations were measured in 22 medical students before and after their end-of-year examination. There was no significant change in plasma noradrenaline or adrenaline concentrations (+20 +39%, P = 0.08, and −2 +33%, P = 0.36, respectively) nor in platelet concentrations (noradrenaline +6+19%, P = 0.15, and adrenaline +34 +72, P = 0.65). 6. In 53 subjects sampled between 08.00 and 12.00 hours, plasma and platelet noradrenaline concentrations were significantly correlated (r, = 0.47, P <0.001), but the relationship between plasma and platelet adrenaline concentrations in these subjects did not achieve significance (rs = 0.17, P <0.23). 7. In conclusion, platelet catecholamine concentrations seem to be unaffected by acute short-term stress and may provide a reliable indicator of chronic sympatho-adrenomedullary arousal.
Cite
Citations (35)
The utility of platelet catecholamine determination in assessing sympathetic nervous system activity depends on the extent to which transient fluctuations of plasma catecholamine concentration can affect platelet catecholamine content. In order to quantitate the relationship between plasma and platelet catecholamine content, the concentrations of norepinephrine, epinephrine and dopamine needed to produce an increase in platelet catecholamines in vitro were determined. The threshold for epinephrine accumulation was 10(-9)M while the thresholds for norepinephrine and dopamine were an order of magnitude higher. The uptake of catecholamines was also found to differ with regard to the time course and the amount of catecholamine accumulated. For example, after 2 h in the presence of equimolar (2 × 10(-8)M) concentrations of catecholamine the platelet content of norepinephrine doubled and epinephrine rose 10-fold and dopamine 20-fold. When platelets that had been loaded with catecholamines were suspended in catecholamine-free buffer, significant amounts of catecholamines were still retained in the platelets after 3 h, but retention of norepinephrine was greater than that of epinephrine. These results indicate the importance of the concentration of the particular catecholamine, duration of exposure of platelets to the catecholamine and the ability of platelets to retain catecholamines, in determining the relationship between plasma and platelet catecholamine content.
Cite
Citations (2)
Corticosterone (CORT) and other glucocorticoids cause peripheral insulin resistance and compensatory increases in β-cell mass. A prolonged high-fat diet (HFD) induces insulin resistance and impairs β-cell insulin secretion. This study examined islet adaptive capacity in rats treated with CORT and a HFD. Male Sprague-Dawley rats (age ∼6 weeks) were given exogenous CORT (400 mg/rat) or wax (placebo) implants and placed on a HFD (60% calories from fat) or standard diet (SD) for 2 weeks (N = 10 per group). CORT-HFD rats developed fasting hyperglycemia (>11 mM) and hyperinsulinemia (∼5-fold higher than controls) and were 15-fold more insulin resistant than placebo-SD rats by the end of ∼2 weeks (Homeostatic Model Assessment for Insulin Resistance [HOMA-IR] levels, 15.08 ± 1.64 vs 1.0 ± 0.12, P < .05). Pancreatic β-cell function, as measured by HOMA-β, was lower in the CORT-HFD group as compared to the CORT-SD group (1.64 ± 0.22 vs 3.72 ± 0.64, P < .001) as well as acute insulin response (0.25 ± 0.22 vs 1.68 ± 0.41, P < .05). Moreover, β- and α-cell mass were 2.6- and 1.6-fold higher, respectively, in CORT-HFD animals compared to controls (both P < .05). CORT treatment increased p-protein kinase C-α content in SD but not HFD-fed rats, suggesting that a HFD may lower insulin secretory capacity via impaired glucose sensing. Isolated islets from CORT-HFD animals secreted more insulin in both low and high glucose conditions; however, total insulin content was relatively depleted after glucose challenge. Thus, CORT and HFD, synergistically not independently, act to promote severe insulin resistance, which overwhelms islet adaptive capacity, thereby resulting in overt hyperglycemia.
Hyperinsulinemia
Corticosterone
Cite
Citations (46)
The rate of turnover of radioactive catecholamine in several regions of the sympathetic nervous system of mice has been measured by a technique involving endogenous labeling. Catecholamine storage sites were labeled by the intravenous administration of radioactive dopa or tyrosine, both precursors of catecholamine, in amounts insufficient to cause measurable change in the catecholamine content of the tissues under study. The subsequent fall in specific activity served as an index of the rate of turnover.
Conversion of DL-dopa-H3 into catecholamine proceeded very quickly; 4 hours after it had been injected, dopa-H3 had practically disappeared from blood and tissues and nearly all of the labeled catecholamine in the brain, heart, liver and adrenal gland was norepinephrine and/or epinephrine.
Specific activity of catecholamine in each organ was determined at intervals up to 4 days. In brain, liver and heart specific activity fell steeply at first (t½ = 4 to 8 hours) then gressively more slowly so that after 24 hours t½ = 18 hours. This implies either that the labeled catecholamine was distributed in more than one pool, each of which was turning over at a different rate and/or that catecholamine stores were nonhomogeneously labeled. In adrenal glands specific activity of catecholamine either rose or did not change during the first 8 hours after dopa-H3 was injected, probably because circulating catecholamine of high specific activity was being taken up and stored. From 8 hours to 3 days specific activity fell at a disappearance half-time of about 1 week.
The disappearance curve for spleen may not for the first 6 hours be taken to represent change in specific activity of beta -bydroxylated catecholamine. However, after this time the specific activity diminished with a t½ of approximately 24 hours.
When C14- or H3-tyrosine was given intravenously as precursor, catecholamine in brain was more heavily labeled than in any of the other organs which were studied. The rate of fall of specific activity in the adrenal medulla closely resembled that observed when labeling was with dopa-H3. The disappearance curves for heart, liver and brain lacked an initial rapid fall but after 24 hours the slopes were similar to those found when dopa-H3 was used as precursor.
Sympathetic nervous system
Cite
Citations (44)
Abstract Dysregulation of the adipoinsular axis in male obese Zucker diabetic fatty (ZDF; fa/fa) rats, a model of type 2 diabetes, results in chronic hyperinsulinemia and increased de novo lipogenesis in islets, leading to β-cell failure and diabetes. Diazoxide (DZ; 150 mg/kg·d), an inhibitor of insulin secretion, was administered to prediabetic ZDF animals for 8 wk as a strategy for prevention of diabetes. DZ reduced food intake (P < 0.02) and rate of weight gain only in ZDF rats (P < 0.01). Plasma insulin response to glucose load was attenuated in DZ-Zucker lean rats (ZL; P < 0.01), whereas DZ-ZDF had higher insulin response to glucose than controls (P < 0.001). DZ improved hemoglobin A1c (P < 0.001) and glucose tolerance in ZDF (P < 0.001), but deteriorated hemoglobin A1c in ZL rats (P < 0.02) despite normal tolerance in the fasted state. DZ lowered plasma leptin (P < 0.001), free fatty acid, and triglyceride (P < 0.001) levels, but increased adiponectin levels (P < 0.02) only in ZDF rats. DZ enhanced β3-adrenoreceptor mRNA (P < 0.005) and adenylate cyclase activity (P < 0.01) in adipose tissue from ZDF rats only, whereas it enhanced islet β3- adrenergic receptor mRNA (P < 0.005) but paradoxically decreased islet adenylate cyclase activity (P < 0.005) in these animals. Islet fatty acid synthase mRNA (P < 0.03), acyl coenzyme A carboxylase mRNA (P < 0.01), uncoupling protein-2 mRNA (P < 0.01), and triglyceride content (P < 0.005) were only decreased in DZ-ZDF rats, whereas islet insulin mRNA and insulin content were increased in DZ-ZDF (P < 0.01) and DZ-ZL rats (P < 0.03). DZ-induced β-cell rest improved the lipid profile, enhanced the metabolic efficiency of insulin, and prevented β-cell dysfunction and diabetes in diabetes-prone animals. This therapeutic strategy may be beneficial in preventing β-cell failure and progression to diabetes in humans.
Hyperinsulinemia
Lipogenesis
Diazoxide
Cite
Citations (39)
To examine the alteration of the plasma free-catecholamine level during hemopurification in a patient with pheochromocytoma, the levels of plasma free-catecholamine and total catecholamine in the filtrate were monitored pre- and post-hemopurification. Approximately 100 micrograms of total catecholamine was removed by the hemopurification procedure though the high level of plasma-free catecholamine remained unaltered.
Cite
Citations (7)
In patients with adrenal tumor, the importance of platelet catecholamine was examined. In patients with pheochromocytoma, not only preoperative catecholamine concentrations in blood and urine but also platelet catecholamine content were abnormally high as compared to patients with other adrenal tumors (pheochromocytoma for NE 3383 and E 311, no pheochromocytoma for NE 235 and E 24 pg.mg-1 protein). In the patient with pheochromocytoma, plasma catecholamine concentration showed its peak during the manipulation of the tumor during operation, and it decreased rapidly and returned to normal level the day after operation. On the other hand, platelet catecholamine content showed its peak after operation and returned to normal range on the 7th postoperative day. These results suggest that determination of platelet catecholamine content is useful for pre-operative diagnosis of pheochromocytoma, and that catecholamine in platelet modulates sudden fluctuation in plasma catecholamine concentration.
Normetanephrine
Cite
Citations (0)
The nationally-recognized Susquehanna
Chorale will delight audiences of all
ages with a diverse mix of classic and
contemporary pieces. The ChoraleAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂA¢AÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂs
performances have been described
as AÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂA¢AÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂemotionally unfiltered, honest
music making, successful in their
aim to make the audience feel,
to be moved, to be part of the
performance - and all this while
working at an extremely high
musical level.AÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂA¢AÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂA Experience choral
singing that will take you to new
heights!
Cite
Citations (0)