scholarly journals In vivoEffects of Temperature on the Heart and Pyloric Rhythms in the Crab,Cancer borealis

2018 ◽  
Author(s):  
Dahlia Kushinsky ◽  
Ekaterina O. Morozova ◽  
Eve Marder
Keyword(s):  
Heart Rhythm ◽  
Critical Temperatures ◽  
Cancer Borealis ◽  
Sensory Inputs ◽  
Temperature Ramps ◽  
Summary Statement ◽  
Pyloric Muscle ◽  
Pyloric Rhythm

Summary StatementTemperature elevation increases the frequency of the heart and pyloric rhythms of the crab,Cancer borealis, but the heart rhythm has a higher critical temperature than the pyloric rhythm.AbstractThe heart and pyloric rhythms of crustaceans have been studied separately and extensively over many years. Local and hormonal neuromodulation and sensory inputs onto these central pattern generating circuits play a significant role in the animals’ responses to perturbations, but are usually lost or removed duringin vitrostudies. To examine simultaneously thein vivomotor output of the heart and pyloric rhythms, we used photoplethysmography (PPG). In the population measured (n = 49), the heart rhythm frequencies ranged from 0.3–2.3 Hz. The pyloric rhythms varied from 0.2–1.6 Hz. During multiple hour-long recordings, many animals held at control temperature showed strong inhibitory bouts in which the heart decreased in frequency or become quiescent and the pyloric rhythm also decreased in frequency. Many animals show significant coherence in frequency between the rhythms at the frequency of the heart rhythm. We measured the simultaneous responses of the rhythms to temperature ramps by heating or cooling the saline bath while recording both the heart and pyloric muscle movements. Q10s, critical temperatures (temperatures at which function is compromised), and changes in frequency were calculated for each of the rhythms tested. The heart rhythm was more robust to high temperature than the pyloric rhythm.

scholarly journals Smad9 is a key player of follicular selection in goose via keeping the balance of LHR transcription

2017 ◽  
Author(s):  
Daolun Yu ◽  
Fanghui Chen ◽  
Li Zhang ◽  
Hejian Wang ◽  
Jie Chen ◽  
...  
Keyword(s):  
Chromatin Immunoprecipitation ◽  
Hormone Receptor ◽  
Egg Production ◽  
Follicular Development ◽  
Luteinizing Hormone Receptor ◽  
Summary Statement ◽  
Follicular Selection ◽  
New Strategies

ABSTRACTThe egg production of poultry depends on follicular development and selection. However, the mechanism of selecting the priority of hierarchical follicles is completely unknown. Smad9 is one of the important transcription factors in BMP/Smads pathway and involved in goose follicular initiation. To explore its potential role in goose follicle hierarchy determination, we first blocked Smad9 expression using BMP typeⅠreceptor inhibitor LDN–193189 both in vivo and in vitro. Unexpectedly, LDN–193189 administration could dramatically suppress Smad9 level and elevate egg production (7.08 eggs / bird, P< 0.05) of animals, and the estradiol (E2) and luteinizing hormone receptor (LHR) level were significantly increased (P< 0.05), but the progesterone (P4) and follicle stimulating hormone receptor (FSHR) mRNA remain unchanged. Surprisingly, Smad9 knockdown notably attenuated (P< 0.05) in E2, P4, FSHR and LHR level in goose granulosa cells (gGCs). Further chromatin immunoprecipitation (ChIP) assay of gGCs revealed that Smad9, served as a sensor of balance, bound to the LHR promoter regulating its transcription. These findings demonstrated that Smad9 is differentially expressed in goose follicles, and acts as a key player in controlling goose follicular selection.SUMMARY STATEMENTTo study the hierarchical development mechanism of avian follicle, new strategies can be found to improve the egg production of low-yielding poultry, such as geese.

Inhibitory function of VIP-PHI and galanin in canine pylorus

1989 ◽  
Vol 256 (4) ◽  
pp. G789-G797 ◽  
Author(s):  
H. D. Allescher ◽  
E. E. Daniel ◽  
J. Dent ◽  
J. E. Fox
Keyword(s):  
Field Stimulation ◽  
Intraduodenal Infusion ◽  
Inhibitory Function ◽  
Excitatory Pathways ◽  
Neural Inhibition ◽  
Before And After ◽  
Pyloric Muscle ◽  
Stimulation Of

Contractions of canine pylorus and adjacent muscles were recorded with antral and duodenal strain gauges and a Dent sleeve manometric assembly with additional side holes in the pylorus. In vivo, vasoactive intestinal polypeptide (VIP) and peptide histamine isoleucine (PHI) given through the gastroepiploic artery inhibited both spontaneous and acetylcholine-induced pyloric contractions, before and after neural blockade with tetrodotoxin. Galanin inhibited only nerve-stimulated contractions. VIP greater than PHI much greater than galanin inhibited pyloric motor activity initiated by field stimulation of duodenal intramural nerves or intraduodenal infusion of 0.1 N HCl. In vitro, forskolin or field stimulation of nerves inhibited contractions of the pyloric muscle induced by various agonists but VIP-PHI failed to inhibit these contractions on two-thirds of the strips. The in vivo results suggest that VIP (or PHI) may be an inhibitory mediator in the pylorus acting directly on smooth muscle. Galanin may inhibit neural excitatory pathways in the pylorus. However, the structures on which VIP and PHI act in vivo may have become nonfunctional in vitro and other mediators account for the neural inhibition observed in isolated strips.

Confocal microscopic analysis of fluorescein compartmentation within crab urinary bladder cells

1994 ◽  
Vol 267 (1) ◽  
pp. R16-R25 ◽  
Author(s):  
D. S. Miller ◽  
D. M. Barnes ◽  
J. B. Pritchard
Keyword(s):  
Urinary Bladder ◽  
Proximal Tubule ◽  
Organic Anion ◽  
Microscopic Analysis ◽  
Microtubule Inhibitor ◽  
Cancer Borealis ◽  
Anion Secretion ◽  
Bladder Cells

Fluorescein (FL), a fluorescent organic anion, is compartmentalized in cells of organic anion-secreting epithelia, e.g., OK cells, teleost proximal tubule, and crab (Cancer borealis) urinary bladder, a proximal tubule analogue. To further examine the processes involved, FL uptake and distribution were studied in C. borealis urinary bladder cells using epifluorescence and laser confocal microscopy combined with video-image analysis. Intracellular FL was about evenly split between diffuse and punctate compartments after in vitro or in vivo loading. Treatments that affected FL transport into cells (incubation with p-aminohippuric acid or glutarate) altered the FL content of both compartments. However, nocodazole, a microtubule inhibitor, did not affect diffuse FL but significantly reduced punctate FL. Finally, confocal analysis indicated that individual sites of punctate FL accumulation moved in the secretory direction at 0.83 micron/min. Nocodazole nearly abolished this movement and significantly reduced transepithelial organic anion secretion. Thus, in crab urinary bladder, a substantial fraction of total cellular FL is sequestered in vesicles, and these vesicles move in the secretory direction, by a microtubule-dependent process.

scholarly journals Phase maintenance in a rhythmic motor pattern during temperature changes in vivo

2014 ◽  
Vol 111 (12) ◽  
pp. 2603-2613 ◽  
Author(s):  
Wafa Soofi ◽  
Marie L. Goeritz ◽  
Tilman J. Kispersky ◽  
Astrid A. Prinz ◽  
Eve Marder ◽  
...  
Keyword(s):  
Motor Pattern ◽  
Stomatogastric Nervous System ◽  
Cancer Borealis ◽  
Environmental Perturbations ◽  
Phase Maintenance ◽  
Pyloric Dilator ◽  
Similar Temperature ◽  
Intact Crab

Central-pattern-generating neural circuits function reliably throughout an animal's life, despite constant molecular turnover and environmental perturbations. Fluctuations in temperature pose a problem to the nervous systems of poikilotherms because their body temperature follows the ambient temperature, thus affecting the temperature-dependent dynamics of various subcellular components that constitute neuronal circuits. In the crustacean stomatogastric nervous system, the pyloric circuit produces a triphasic rhythm comprising the output of the pyloric dilator, lateral pyloric, and pyloric constrictor neurons. In vitro, the phase relationships of these neurons are maintained over a fourfold change in pyloric frequency as temperature increases from 7°C to 23°C. To determine whether these temperature effects are also found in intact crabs, in the presence of sensory feedback and neuromodulator-rich environments, we measured the temperature dependence of the pyloric frequency and phases in vivo by implanting extracellular electrodes into Cancer borealis and Cancer pagurus and shifting tank water temperature from 11°C to 26°C. Pyloric frequency in the intact crab increased significantly with temperature (Q10 = 2–2.5), while pyloric phases were generally conserved. For a subset of the C. borealis experiments, animals were subsequently dissected and the stomatogastric ganglion subjected to a similar temperature ramp in vitro. We found that the maximal frequency attained at high temperatures in vivo is lower than it is under in vitro conditions. Our results demonstrate that, over a wide temperature range, the phases of the pyloric rhythm in vivo are generally preserved, but that the frequency range is more restricted than it is in vitro.

scholarly journals Bradycardic mice undergo effective heart rate improvement after specific homing to the sino-atrial node and differentiation of adult muscle derived stem cells

2018 ◽  
Author(s):  
Pietro Mesirca ◽  
Daria Mamaeva ◽  
Isabelle Bidaud ◽  
Matthias Baudot ◽  
Romain Davaze ◽  
...  
Keyword(s):  
Stem Cells ◽  
Heart Rate ◽  
Heart Rhythm ◽  
Mutant Mice ◽  
Recipient Mouse ◽  
Wild Type ◽  
Cardiac Pacemakers ◽  
Lineage Differentiation

AbstractCurrent treatments for heart automaticity disorders still lack a safe and efficient source of stem cells to restore normal biological pacemaking. Since adult Muscle-Derived Stem Cells (MDSC) show multi-lineage differentiation in vitro including into spontaneously beating cardiomyocytes, we questioned whether they could effectively differentiate into cardiac pacemakers, a specific population of cardiomyocytes producing electrical impulses in the sino-atrial node (SAN) of adult heart. We show here that beating cardiomyocytes, differentiated from MDSC in vitro, exhibit typical characteristics of cardiac pacemakers: expression of markers of the SAN lineage Hcn4, Tbx3 and Islet1, as well as spontaneous calcium transients and hyperpolarization-activated “funny” current and L-type Cav1.3 channels. Pacemaker-like myocytes differentiated in vitro from Cav1.3-deficient mouse stem cells produced slower rate of spontaneous Ca2+ transients, consistent with the reduced activity of native pacemakers in mutant mice. In vivo, undifferentiated wild type MDSC migrated and homed with increased engraftment to the SAN of bradycardic mutant Cav1.3-/- within 2-3 days after systemic I.P. injection. The increased homing of MDSCs corresponded to increased levels of the chemokine SDF1 and its receptor CXCR4 in mutant SAN tissue and was ensued by differentiation of MDSCs into Cav1.3-expressing pacemaker-like myocytes within 10 days and a significant improvement of the heart rate maintained for up to 40 days. Optical mapping and immunofluorescence analyses performed after 40 days on SAN tissue from transplanted wild type and mutant mice showed MDSCs integrated as pacemaking cells both electrically and functionally within recipient mouse SAN. These findings identify MDSCs as directly transplantable stem cells that efficiently home, differentiate and improve heart rhythm in mouse models of congenital bradycardia.

scholarly journals Forces driving cell sorting in Hydra

2017 ◽  
Author(s):  
Olivier Cochet-Escartin ◽  
Tiffany T. Locke ◽  
Winnie H. Shi ◽  
Robert E. Steele ◽  
Eva-Maria S. Collins
Keyword(s):  
Cell Sorting ◽  
Single Cells ◽  
Cell Types ◽  
Biological Organization ◽  
3 Dimensional ◽  
Physical Mechanisms ◽  
Summary Statement ◽  
Endodermal Cells

AbstractCell sorting, whereby a heterogeneous cell mixture organizes into distinct tissues, is a fundamental patterning process in development. So far, most studies of cell sorting have relied either on 2-dimensional cellular aggregates, in vitro situations that do not have a direct counterpart in vivo, or were focused on the properties of single cells. Here, we report the first multiscale experimental study on 3-dimensional regenerating Hydra aggregates, capable of reforming a full animal. By quantifying the kinematics of single cell and whole aggregate behaviors, we show that no differences in cell motility exist among cell types and that sorting dynamics follow a power law. Moreover, we measure the physical properties of separated tissues and determine their viscosities and surface tensions. Based on our experimental results and numerical simulations, we conclude that tissue interfacial tensions are sufficient to explain Hydra cell sorting. Doing so, we illustrate D’Arcy Thompson’s central idea that biological organization can be understood through physical principles, an idea which is currently re-shaping the field of developmental biology.Summary statementHydra regenerates after dissociation into single cells. We show how physical mechanisms can explain the first step of regeneration, whereby ectodermal and endodermal cells sort out to form distinct tissue layers.

scholarly journals Myo1e modulates the recruitment of B cells to inguinal lymph nodes

2019 ◽  
Author(s):  
Daniel Alberto Girón-Pérez ◽  
Eduardo Vadillo ◽  
Michael Schnoor ◽  
Leopoldo Santos-Argumedo
Keyword(s):  
Cell Migration ◽  
B Cells ◽  
Lymph Nodes ◽  
Signaling Pathway ◽  
High Endothelial Venules ◽  
Long Tail ◽  
Summary Statement ◽  
And Migration

AbstractThe recruitment of leukocyte to high endothelium venules and their migration to the lymph nodes are critical steps to initiate an immune response. Cell migration is regulated by the actin cytoskeleton where myosins have a very import role. Myo1e is a long tail class I myosin highly expressed in B cells that not have been studied in the context of cell migration. By using an in vivo model, through the use of intravital microscopy, we demonstrated the relevance of Myo1e in the adhesion and the migration of B cells in high endothelial venules. These observations were confirmed by in vitro experiments. We also registered a reduction in the expression of integrins and F-actin in the protrusion of B lymphocytes membrane. Deficiencies in vesicular trafficking can explain the decrease of integrins on the surface. Interestingly, Myo1e is associated with focal adhesion kinase (FAK). The lack of Myo1e affected the phosphorylation of FAK and AKT, and the activity of RAC-1, disturbing the FAK/PI3K/RAC-1 signaling pathway. Together, our results indicate critical participation of Myo1e in the mechanism of B cell migration.Summary statementMyo1e participate in the adhesion and migration in the high endothelial venules by regulation of integrins and the PI3K/FAK/RAC-1 signaling pathway.

Humoral induction of pyloric rhythmic output in lobster stomatogastric ganglion: in vivo and in vitro studies

1992 ◽  
Vol 163 (1) ◽  
pp. 209-230
Author(s):  
E. Rezer ◽  
M. Moulins
Keyword(s):  
Blood Serum ◽  
Stomatogastric Ganglion ◽  
In Vitro Studies ◽  
In Vitro Experiments ◽  
Experimental Conditions ◽  
Pyloric Network ◽  
Pyloric Rhythm

In the lobster Jasus lalandii, 14 neurones of the stomatogastric ganglion (STG) are organized in a network that produces rhythmic pyloric outputs. In vitro experiments have shown that the STG neurones receive, via the stomatogastric nerve (stn), neuromodulatory inputs that influence the expression of the bursting properties of the neurones and the ability of the network to produce its rhythmic output. In contrast to these in vitro observations, in vivo transection of the stn does not abolish the pyloric rhythm. Rhythmic output can be recorded by electromyography immediately after stn transection and for up to 2 years afterwards. We have shown that, under these experimental conditions, the STG appears to be isolated from any neuronal input that might account for the maintenance of the rhythmic output. Experiments carried out in the 2 days after stn transection showed that an in vitro preparation of the isolated STG was unable to produce any rhythmic output, but blood serum added to the system could restore the pyloric output. These results suggest strongly that the pyloric network receives neural and humoral modulatory influences in parallel and that each type of influence alone is able to maintain the bursting capability of the pyloric neurones.

Induction and Differentiation of Dental Epithelium in Vivo and in Vitro

1982 ◽  
Vol 40 ◽  
pp. 142-145
Author(s):  
E. J. Kollar
Keyword(s):  
Connective Tissue ◽  
Oral Mucosa ◽  
Basal Lamina ◽  
Functional Derivatives ◽  
Specific Source ◽  
Dental Epithelium ◽  
Connective Tissue Stroma

The differentiation and maintenance of many specialized epithelial structures are dependent on the underlying connective tissue stroma and on an intact basal lamina. These requirements are especially stringent in the development and maintenance of the skin and oral mucosa. The keratinization patterns of thin or thick cornified layers as well as the appearance of specialized functional derivatives such as hair and teeth can be correlated with the specific source of stroma which supports these differentiated expressions.

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