scholarly journals THERMAL ACCLIMATION ALTERS BOTH ADRENERGIC SENSITIVITY AND ADRENOCEPTOR DENSITY IN CARDIAC TISSUE OF RAINBOW TROUT

1993 ◽  
Vol 181 (1) ◽  
pp. 27-48 ◽  
Author(s):  
J. E. Keen ◽  
D. M. Vianzon ◽  
A. P. Farrell ◽  
G. F. Tibbits
Keyword(s):  
Rainbow Trout ◽  
Cardiac Tissue ◽  
Radioligand Binding ◽  
Temperature Acclimation ◽  
Effect Of Temperature ◽  
Acclimation Temperature ◽  
Binding Studies ◽  
Tension Development

We examined the effect of temperature acclimation on the sensitivity of the rainbow trout heart to adrenaline and on the density of beta-adrenoceptors. The sensitivity of the heart was assessed using in situ working perfused heart and in vitro isometric ventricular strip preparations. When tested in situ and at acclimation temperature, hearts from fish acclimated to 8°C were approximately 10-fold more sensitive to adrenaline-supplemented perfusate than were hearts from fish acclimated to 18°C. The concentrations required for half-maximal stimulation (EC50) of myocardial power output were 1.9×10- 8 mol l-1 adrenaline and 1.7×10-7 mol l-1 adrenaline for hearts acclimated to 8°C and 18°C, respectively. In vitro, isometric ventricular strip preparations demonstrated a similar increase in adrenergic sensitivity with cold-acclimation. The EC50 values for maximal tension development were 2.7×10-7 mol l-1 adrenaline (8°C-acclimated) and 1.1×10-6 mol l-1 adrenaline (18°C-acclimated) when tested at acclimation temperature. This shift in adrenergic sensitivity was a function of the temperature acclimation because changes in bath temperature per se, either from 8°C to 18°C for 8°C- acclimated hearts or from 18°C to 8°C for 18°C-acclimated hearts, had no significant effect on the concentration-response curve for adrenaline. We conducted radioligand binding studies with [125I]iodocyanopindolol and propranolol to quantify the beta-adrenoceptor density (Bmax) of both homogenates and isolated sarcolemmal fractions of ventricles from rainbow trout acclimated to either 8°C or 18°C. The Bmax for isolated sarcolemmal fractions was significantly higher in the 8°C-acclimated group, but the Bmax of ventricular homogenates was not significantly different in the two acclimation groups. No significant differences in dissociation constant (Kd) were apparent in either the homogenates or sarcolemmal fractions. These results suggest that cardiac tissue from rainbow trout acclimated to 8°C has a greater cell surface adrenoceptor population available for beta-antagonist binding. This might explain the heightened cardiac sensitivity to adrenaline observed in situ and in vitro in 8°C-acclimated fish.

scholarly journals Construction of a mammalian embryo model from stem cells organized by a morphogen signalling centre

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Peng-Fei Xu ◽  
Ricardo Moraes Borges ◽  
Jonathan Fillatre ◽  
Maraysa de Oliveira-Melo ◽  
Tao Cheng ◽  
...  
Keyword(s):  
Stem Cells ◽  
Cell Tracking ◽  
Cardiac Tissue ◽  
Embryonic Stem ◽  
Mammalian Embryo ◽  
Wide Range ◽  
Vitro Model ◽  
Neurula Stage

AbstractGenerating properly differentiated embryonic structures in vitro from pluripotent stem cells remains a challenge. Here we show that instruction of aggregates of mouse embryonic stem cells with an experimentally engineered morphogen signalling centre, that functions as an organizer, results in the development of embryo-like entities (embryoids). In situ hybridization, immunolabelling, cell tracking and transcriptomic analyses show that these embryoids form the three germ layers through a gastrulation process and that they exhibit a wide range of developmental structures, highly similar to neurula-stage mouse embryos. Embryoids are organized around an axial chordamesoderm, with a dorsal neural plate that displays histological properties similar to the murine embryo neuroepithelium and that folds into a neural tube patterned antero-posteriorly from the posterior midbrain to the tip of the tail. Lateral to the chordamesoderm, embryoids display somitic and intermediate mesoderm, with beating cardiac tissue anteriorly and formation of a vasculature network. Ventrally, embryoids differentiate a primitive gut tube, which is patterned both antero-posteriorly and dorso-ventrally. Altogether, embryoids provide an in vitro model of mammalian embryo that displays extensive development of germ layer derivatives and that promises to be a powerful tool for in vitro studies and disease modelling.

scholarly journals Acute and chronic influence of temperature on red blood cell anion exchange

2001 ◽  
Vol 204 (1) ◽  
pp. 39-45 ◽  
Author(s):  
F.B. Jensen ◽  
T. Wang ◽  
J. Brahm
Keyword(s):  
Rainbow Trout ◽  
Blood Cell ◽  
Anion Exchange ◽  
Temperature Sensitivity ◽  
Red Blood Cell ◽  
Temperature Acclimation ◽  
Freshwater Turtle ◽  
Acclimation Temperature ◽  
Published Data ◽  
Rainbow Trout Oncorhynchus Mykiss

Unidirectional (36)Cl(−) efflux via the red blood cell anion exchanger was measured under Cl(−) self-exchange conditions (i.e. no net flow of anions) in rainbow trout Oncorhynchus mykiss and red-eared freshwater turtle Trachemys scripta to examine the effects of acute temperature changes and acclimation temperature on this process. We also evaluated the possible adaptation of anion exchange to different temperature regimes by including our previously published data on other animals. An acute temperature increase caused a significant increase in the rate constant (k) for unidirectional Cl(−) efflux in rainbow trout and freshwater turtle. After 3 weeks of temperature acclimation, 5 degrees C-acclimated rainbow trout showed only marginally higher Cl(−) transport rates than 15 degrees C-acclimated trout when compared at the same temperature. Apparent activation energies for red blood cell Cl(−) exchange in trout and turtle were lower than values reported in endothermic animals. The Q(10) for red blood cell anion exchange was 2.0 in trout and 2.3 in turtle, values close to those for CO(2) excretion, suggesting that, in ectothermic animals, the temperature sensitivity of band-3-mediated anion exchange matches the temperature sensitivity of CO(2) transport (where red blood cell Cl(−)/HCO(3)(−) exchange is a rate-limiting step). In endotherms, such as man and chicken, Q(10) values for red blood cell anion exchange are considerably higher but are no obstacle to CO(2) transport, because body temperature is normally kept constant at values at which anion exchange rates are high. When compared at constant temperature, red blood cell Cl(−) permeability shows large differences among species (trout, carp, eel, cod, turtle, alligator, chicken and man). Cl(−) permeabilities are, however, remarkable similar when compared at preferred body temperatures, suggesting an appropriate evolutionary adaptation of red blood cell anion exchange function to the different thermal niches occupied by animals.

PDGF receptors in the rat CNS: during late neurogenesis, PDGF alpha-receptor expression appears to be restricted to glial cells of the oligodendrocyte lineage

Development ◽  
1992 ◽  
Vol 115 (2) ◽  
pp. 535-551 ◽  
Author(s):  
N.P. Pringle ◽  
H.S. Mudhar ◽  
E.J. Collarini ◽  
W.D. Richardson
Keyword(s):  
Glial Cells ◽  
Receptor Expression ◽  
Binding Studies ◽  
Temporal And Spatial Distribution ◽  
Inner Limiting Membrane ◽  
Factor Alpha ◽  
The Brain

Using in situ hybridization, we have visualized cells in the rat central nervous system (CNS) that contain mRNA encoding the platelet-derived growth factor alpha receptor (PDGF-alpha R). After embryonic day 16 (E16), PDGF-alpha R mRNA appears to be expressed by a subset of glial cells, but not by neurons. The temporal and spatial distribution of PDGF-alpha R+ cells, together with 125I-PDGF binding studies on subsets of glial cells in vitro, suggests that PDGF-alpha R may be expressed predominantly, or exclusively, by cells of the oligodendrocyte-type-2 astrocyte (O-2A) lineage. This conclusion is supported by the fact that the numbers of PDGF-alpha R+ cells in developing and adult optic nerves correlate well with independent estimates of the number of O-2A progenitor cells in the nerve at equivalent ages. Small numbers of PDGF-alpha R+ cells are present in the brain at E16, at which time they are found outside the subventricular germinal zones, suggesting that these cells do not express PDGF-alpha R until after, or shortly before they start to migrate away from the subventricular layer towards their final destinations. Reduced numbers of PDGF-alpha R+ cells persist in the adult CNS. PDGF-alpha R is also expressed strongly in the meningeal membranes and choroid plexus, and in the inner limiting membrane of the retina.

3'- and 4'-chloro-substituted analogs of benztropine: intravenous self-administration and in vitro radioligand binding studies in rhesus monkeys

2000 ◽  
Vol 147 (4) ◽  
pp. 426-435 ◽  
Author(s):  
W. L. Woolverton ◽  
J. K. Rowlett ◽  
K. M. Wilcox ◽  
I. A. Paul ◽  
R. H. Kline ◽  
...  
Keyword(s):  
Rhesus Monkeys ◽  
Radioligand Binding ◽  
Self Administration ◽  
Binding Studies ◽  
Radioligand Binding Studies

scholarly journals Bioreactor Platform for Biomimetic Culture and in situ Monitoring of the Mechanical Response of in vitro Engineered Models of Cardiac Tissue

2020 ◽  
Vol 8 ◽  
Author(s):  
Diana Massai ◽  
Giuseppe Pisani ◽  
Giuseppe Isu ◽  
Andres Rodriguez Ruiz ◽  
Giulia Cerino ◽  
...  
Keyword(s):  
Cardiac Tissue ◽  
Mechanical Response ◽  
In Situ Monitoring

In Vitro Hypothermia Enhances Platelet GPIIb-IIIa Activation and P-Selectin Expression 

1998 ◽  
Vol 88 (6) ◽  
pp. 1579-1585 ◽  
Author(s):  
Nauder Faraday ◽  
Brian Rosenfeld
Keyword(s):  
Platelet Function ◽  
Platelet Reactivity ◽  
Effect Of Temperature ◽  
Intrinsic Defect ◽  
Moderate Hypothermia ◽  
Binding Studies ◽  
Profound Hypothermia ◽  
Fibrinogen Binding ◽  
Platelet Binding

Background A clinical bleeding diathesis is associated with hypothermia. Inhibition of platelet reactivity is the purported cause of this coagulopathy despite inconsistent evidence to support this hypothesis. To clarify the effect of temperature on intrinsic platelet function, platelet GPllb-IIIa activation and P-selectin expression were assessed under normothermic and hypothermic conditions in vitro. Methods Blood was obtained by venipuncture from healthy volunteers. Platelet activation was assessed by aggregometry and by cytometric analysis of platelet binding of fibrinogen, PAC-1, and P-selectin antibodies. Measurements were made at normothermia (37 degrees C), moderate hypothermia (33 degrees C), and profound hypothermia (22 degrees C) after stimulating samples with adenosine diphosphate (ADP), collagen, or thrombin receptor activating peptide. Results Agonist-induced platelet aggregation and fibrinogen binding were significantly greater at 22 degrees C and 33 degrees C than at 37 degrees C. Platelet fibrinogen binding values to 20 micro M ADP were 23,400, 14,300, and 9,700 molecules/platelet at 22 degrees C, 33 degrees C, and 37 degrees C, respectively. The aggregation responses of platelets that were cooled and rewarmed were indistinguishable from those of platelets maintained at 37 degrees C throughout the study. Platelet binding of PAC-1 and P-selectin antibodies was greater under hypothermic conditions. Conclusions Aggregation, fibrinogen binding, PAC-1 binding, and P-selectin antibody binding studies showed that platelet GPIIb-IIIa activation and alpha-granule release were enhanced at hypothermic temperatures. Thus hypothermia appears to increase the ability of platelets to respond to activating stimuli. The coagulopathy associated with hypothermia is not likely to be the result of an intrinsic defect in platelet function.

Sealed-Jar Bioassays for Pulpmill Effluent Toxicity: Effects of Fish Species and Temperature

1977 ◽  
Vol 34 (9) ◽  
pp. 1389-1396 ◽  
Author(s):  
Michael R. Gordon ◽  
Donald J. McLeay
Keyword(s):  
Rainbow Trout ◽  
Fish Species ◽  
Test Temperature ◽  
Coho Salmon ◽  
Temperature Acclimation ◽  
Salmo Gairdneri ◽  
Acclimation Temperature ◽  
Specific Response ◽  
Oxygen Utilization ◽  
Effluent Toxicity

To standardize the sealed-jar bioassay for optimum sensitivity to whole bleached kraft pulpmill effluent, experiments were designed to assess the effects of test temperature, acclimation temperature, and fish species. Coho salmon (Oncorhynchus kisutch) conformed to a previously recognized test paradigm by showing progressively decreased oxygen utilization with increasing toxicant concentrations; however, rainbow trout (Salmo gairdneri) did not. In concentrations of effluent < 1.5 LC50, rainbow trout used significantly more oxygen than control groups, while coho salmon used significantly less oxygen. The sensitivity of these responses was influenced by test temperature and acclimation temperature. Results for coho confirmed that this species was most sensitive to effluent when tested at ambient room temperature. Both species showed significantly decreased oxygen utilization in effluent concentrations > 1.5 LC50 irrespective of test temperature or acclimation temperature. The significance of these responses is discussed, and the applicability of sealed-jar bioassays for assessing the acute toxicity of pulpmill effluents is reviewed. Key words: residual oxygen bioassay, sealed-jar bioassay, pulpmill effluent toxicity, temperature, hyperthermia, respiration, hypoxia, species-specific response

scholarly journals Effects of Thermal Acclimation on the Tolerance of Bactrocera zonata (Diptera: Tephritidae) to Hydric Stress

2021 ◽  
Vol 12 ◽  
Author(s):  
Michael Ben-Yosef ◽  
Eleni Verykouki ◽  
Yam Altman ◽  
Esther Nemni-Lavi ◽  
Nikos T. Papadopoulos ◽  
...  
Keyword(s):  
Fruit Fly ◽  
Temperature Acclimation ◽  
Effect Of Temperature ◽  
Acclimation Temperature ◽  
Desiccation Resistance ◽  
Terrestrial Invertebrates ◽  
Bactrocera Zonata ◽  
Significant Difference ◽  
Males And Females ◽  
Survival Patterns

Insects, similarly to other small terrestrial invertebrates, are particularly susceptible to climatic stress. Physiological adjustments to cope with the environment (i.e., acclimation) together with genetic makeup eventually determine the tolerance of a species to climatic extremes, and constrain its distribution. Temperature and desiccation resistance in insects are both conditioned by acclimation and may be interconnected, particularly for species inhabiting xeric environments. We determined the effect of temperature acclimation on desiccation resistance of the peach fruit fly (Bactrocera zonata, Tephritidae) – an invasive, polyphagous pest, currently spreading through both xeric and mesic environments in Africa and the Eurasian continent. Following acclimation at three constant temperatures (20, 25, and 30°C), the survival of adult flies deprived of food and water was monitored in extreme dry and humid conditions (&lt;10 and &gt;90% relative humidity, respectively). We found that flies acclimated at higher temperatures were significantly heavier, and contained more lipids and protein. Acclimation temperature significantly and similarly affected the survival of males and females at both high and low humidity conditions. In both cases, flies maintained at 30°C survived longer compared to 20 and 25°C – habituated counterparts. Regardless of the effect of acclimation temperature on survival, overall life expectancy was significantly shortened when flies were assayed under desiccating conditions. Additionally, our experiments indicate no significant difference in survival patterns between males and females, and that acclimation temperature had similar effects after both short (5–10 days) and long (11–20 days) acclimation periods. We conclude that acclimation at 30°C prolongs the survival of B. zonata, regardless of ambient humidity levels. Temperature probably affected survival through modulating feeding and metabolism, allowing for accumulation of larger energetic reserves, which in turn, promoted a greater ability to resist starvation, and possibly desiccation as well. Our study set the grounds for understanding the phenotypic plasticity of B. zonata from the hydric perspective, and for further evaluating the invasion potential of this pest.

scholarly journals Local production and action of adrenomedullin in the rat adrenal zona glomerulosa

1998 ◽  
Vol 156 (3) ◽  
pp. 477-484 ◽  
Author(s):  
S Kapas ◽  
A Martinez ◽  
F Cuttitta ◽  
JP Hinson
Keyword(s):  
In Situ Hybridization ◽  
Inositol Phosphate ◽  
Zona Glomerulosa ◽  
Binding Studies ◽  
Aldosterone Secretion ◽  
Glomerulosa Cells ◽  
Camp Formation ◽  
Zona Glomerulosa Cells

This study was designed to investigate the synthesis and action of adrenomedullin in the rat adrenal gland. The results obtained from in situ hybridization and immunocytochemical studies suggest that adrenomedullin is synthesized not only in the medulla, but also within the zona glomerulosa of the rat adrenal cortex. Findings from in situ hybridization and binding studies also suggested that specific adrenomedullin receptors are expressed in the zona glomerulosa, and that low levels are present in the inner zones of the cortex. The Kd of the zona glomerulosa adrenomedullin receptor (5.5 nmol/l) suggests that it may respond to locally produced adrenomedullin rather than circulating concentrations of the peptide, which are in a lower range. It was found that adrenomedullin acted on zona glomerulosa cells in vitro to stimulate aldosterone release and cAMP formation, but in this tissue did not stimulate inositol phosphate turnover. The effect of adrenomedullin on aldosterone secretion was significantly attenuated by a protein kinase A inhibitor, suggesting that cAMP mediates the effects of adrenomedullin on aldosterone secretion. Adrenomedullin did not significantly affect the response of zona glomerulosa cells to stimulation by either ACTH or angiotensin II. Adrenomedullin did not affect the release of catecholamines, either adrenaline or noradrenaline, by intact adrenal capsular tissue. These data suggest that both adrenomedullin and its specific receptor are expressed in the rat adrenal zona glomerulosa, leading to the hypothesis that adrenomedullin may have an autocrine/paracrine role in the regulation of the rat adrenal zona glomerulosa.

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