Persistence of eupnea and gasping following blockade of both serotonin type 1 and 2 receptors in the in situ juvenile rat preparation

2007 ◽  
Vol 103 (1) ◽  
pp. 220-227 ◽  
Author(s):  
Veronica A. L. Toppin ◽  
Michael B. Harris ◽  
Anna M. Kober ◽  
J. C. Leiter ◽  
Walter M. St.-John
Keyword(s):  
Sodium Current ◽  
Critical Role ◽  
Serotonergic Receptors ◽  
Neural Activities ◽  
Vagal Nerves ◽  
Powerful Mechanism

In severe hypoxia or ischemia, normal eupneic breathing is replaced by gasping, which can serve as a powerful mechanism for “autoresuscitation.” We have proposed that gasping is generated by medullary neurons having intrinsic pacemaker bursting properties dependent on a persistent sodium current. A number of neuromodulators, including serotonin, influence persistent sodium currents. Thus we hypothesized that endogenous serotonin is essential for gasping to be generated. To assess such a critical role for serotonin, a preparation of the perfused, juvenile in situ rat was used. Activities of the phrenic, hypoglossal, and vagal nerves were recorded. We added blockers of type 1 and/or type 2 classes of serotonergic receptors to the perfusate delivered to the preparation. Eupnea continued following additions of any of the blockers. Changes were limited to an increase in the frequency of phrenic bursts and a decline in peak heights of all neural activities. In ischemia, gasping was induced following any of the blockers. Few statistically significant changes in parameters of gasping were found. We thus did not find a differential suppression of gasping, compared with eupnea, following blockers of serotonin receptors. Such a differential suppression had been proposed based on findings using an in vitro preparation. We hypothesize that multiple neurotransmitters/neuromodulators influence medullary mechanisms underlying the neurogenesis of gasping. In greatly reduced in vitro preparations, the importance of any individual neuromodulator, such as serotonin, may be exaggerated compared with its role in more intact preparations.

scholarly journals Corticotropin-Releasing Hormone (CRH)-Induced Thyrotropin Release Is Directly Mediated through CRH Receptor Type 2 on Thyrotropes

Endocrinology ◽  
2003 ◽  
Vol 144 (12) ◽  
pp. 5537-5544 ◽  
Author(s):  
Bert De Groef ◽  
Nesya Goris ◽  
Lutgarde Arckens ◽  
Eduard R. Kühn ◽  
Veerle M. Darras
Keyword(s):  
Cell Types ◽  
Melanocortin Receptor ◽  
Tsh Secretion ◽  
Partial Cdna ◽  
Specific Antagonist ◽  
Releasing Effect

Abstract CRH is known as the main stimulator of ACTH release. In representatives of all nonmammalian vertebrates, CRH has also been shown to induce TSH secretion, acting directly at the level of the pituitary. We have investigated which cell types and receptors are involved in CRH-induced TSH release in the chicken (Gallus gallus). Because a lack of CRH type 1 receptors (CRH-R1) on the chicken thyrotropes has been previously reported, two hypotheses were tested using in situ hybridization and perifusion studies: 1) TSH secretion might be induced in a paracrine way involving melanocortins from the corticotropes; and 2) thyrotropes might express another type of CRH-R. For the latter, we have cloned a partial cDNA encoding the chicken CRH-R2. Neither α-melanotropin (α-MSH) nor its powerful analog Nle4,d-Phe7-MSH could mimic the in vitro TSH-releasing effect of ovine CRH. The nonselective melanocortin receptor blocker SHU91199 did not influence CRH- or TRH-induced TSH secretion. On the other hand, we have found that thyrotropes express CRH-R2 mRNA. The involvement of this CRH receptor in the response of thyrotropes to CRH was further confirmed by the fact that TSH release was stimulated by human urocortin III, a CRH-R2-specific agonist, whereas the TSH response to CRH was completely blocked by the CRH-R blocker astressin and the CRH-R2-specific antagonist antisauvagine-30. We conclude that CRH-induced TSH secretion is mediated by CRH-R2 expressed on thyrotropes.

scholarly journals Effect of Different Fermentation Condition on Estimated Glycemic Index, In Vitro Starch Digestibility, and Textural and Sensory Properties of Sourdough Bread

Foods ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 514
Author(s):  
Hilal Demirkesen-Bicak ◽  
Muhammet Arici ◽  
Mustafa Yaman ◽  
Salih Karasu ◽  
Osman Sagdic
Keyword(s):  
Glycemic Index ◽  
Sensory Properties ◽  
Starch Digestibility ◽  
In Vitro Starch Digestibility ◽  
Whole Wheat ◽  
Sourdough Bread ◽  
Estimated Glycemic Index

This study aimed to evaluate the influence of sourdough fermentation on the estimated glycemic index (eGI), in vitro starch digestibility, and textural and sensory properties of eight experimentally prepared sourdough breads. Wheat and whole wheat flour bread samples were produced under different fermentation conditions (25 °C and 30 °C) and fermentation methods (type-1 and type-2). In type-1 fermentation, sourdough was obtained via spontaneous fermentation. Indigenous strains (Lactobacillus brevis ELB99, Lactiplantibacillus plantarum ELB75, and Saccharomyces cerevisiae TGM55) were used for type-2 fermentation. Fermentation type and temperature significantly affected eGI, the hydrolysis index (HI), the starch fraction, and the textural properties of the samples (p < 0.05). The resistant starch (RS) content increased after fermentation, while rapidly digestible starch (RDS), HI, and eGI decreased. RS values were significantly higher in type-2 than in type-1 at the same temperature for both flour types (p < 0.05). At 25 °C, RS values were higher in both fermentation types. In the white flour samples, eGI values were in the range of 60.8–78.94 and 62.10–78.94 for type-1 and type-2, respectively. The effect of fermentation type on eGI was insignificant (p < 0.05). In the whole flour samples, fermentation type and temperature significantly affected eGI (p < 0.05). The greatest eGI decreases were in whole wheat sourdough bread at 30 °C using type-2 (29.74%). The 30 °C and type-2 samples showed lower hardness and higher specific volume. This study suggests that fermentation type and temperature could affect the eGI and the textural and sensory properties of sourdough bread, and these factors should be considered during bread production. The findings also support the consumption of wheat and whole wheat breads produced by type-2 fermentation due to higher RS and slowly digestible starch (SDS) and lower RDS and eGI values.

scholarly journals First Report ofEurycoma longifoliaJack Root Extract Causing Relaxation of Aortic Rings in Rats

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Bae Huey Tee ◽  
See Ziau Hoe ◽  
Swee Hung Cheah ◽  
Sau Kuen Lam
Keyword(s):  
Erectile Function ◽  
Receptor Activation ◽  
Root Extract ◽  
Ang Ii ◽  
Angiotensin I ◽  
Eurycoma Longifolia ◽  
Vasodilatory Effect

AlthoughEurycoma longifoliahas been studied for erectile function, the blood pressure- (BP-) lowering effect has yet to be verified. Hence, this study aims at investigating the BP-lowering properties of the plant with a view to develop an antihypertensive agent that could also preserve erectile function. Ethanolic root extract was partitioned by hexane, dichloromethane (DCM), ethyl acetate, butanol, and water. The DCM fraction, found to be potent in relaxing phenylephrine- (PE-) precontracted rat aortic rings, was further purified by column chromatography. Subfraction DCM-II, being the most active in relaxing aortae, was studied for effects on the renin-angiotensin and kallikrein-kinin systems in aortic rings. The effect of DCM-II on angiotensin-converting enzyme (ACE) activity was also evaluatedin vitro. Results showed that DCM-II reduced (p<0.05) the contractions evoked by angiotensin I and angiotensin II (Ang II). In PE-precontracted rings treated with DCM-II, the Ang II-induced contraction was attenuated (p<0.05) while bradykinin- (BK-) induced relaxation enhanced (p<0.001).In vitro, DCM-II inhibited (p<0.001) the activity of ACE. These data demonstrate that the vasodilatory effect of DCM-II appears to be mediatedviainhibition of Ang II type 1 receptor and ACE as well as enhancement of Ang II type 2 receptor activation and BK activity.

scholarly journals Differential Activation of CD8+Tumor-Specific Tc1 and Tc2 Cells by an IL-10-Producing Murine Plasmacytoma

1998 ◽  
Vol 6 (3-4) ◽  
pp. 331-342 ◽  
Author(s):  
Christoph Specht ◽  
Hans-Gerd Pauels ◽  
Christian Becker ◽  
Eckehart Kölsch
Keyword(s):  
T Cells ◽  
Immune Responses ◽  
Tumor Cells ◽  
T Cell Subsets ◽  
Early Stages ◽  
Specific Tolerance

The involvement of counteractiveCD8+T-cell subsets during tumor-specific immune responses was analyzed in a syngeneic murine plasmacytoma model.CD8+Tc cells against the immunogenic IL-10-producing BALB/c plasmacytoma ADJ-PC-5 can be easily induced by immunization of BALB/c mice with X-irradiated ADJ-PC-5 tumor cellsin vivoandin vitro. However, the failure of recipient mice to mount a protective Tc response against the tumor during early stages of a real or simulated tumor growth is not due to immunological ignorance, but depends on the induction of tumor-specific tolerance, involving a population of tumorinducedCD8+T cells that are able to inhibit the generation of tumor-specific Tc cells in a primary ADJ-PC-5-specific MLTC, using IFN-γas a suppressive factor. Whereas most longterm cultivated CD8+ADJ-PC-5-specific Tc lines produce type-1 cytokines on stimulation, at least two of them, which were derived from a primary MLTC, display a type-2 cytokine spectrum. Furthermore, the primaryin vitroTc response against ADJ-PC-5 cells shows characteristics of a Tc2 response. The Tc response is strictly depending on tumor-derived IL-10.CD8+Tc cells that are induced in a primary MLTC do not produce IFN-γ, and the tumor-specific Tc response is enhanced by IL-4 but suppressed by IFN-γor IL-12. In contrast, ADJ-PC- 5-specificCD8+Tc cells from immunized mice are IFN-γproducing Tc1 cells. Since the primaryin vitroTc response against the tumor is suppressed even by the smallest numbers of irradiated ADJ-PC-5-specific Tc1 cells via IFN-γthese Tc1 cells behave similar to the suppressiveCD8+T cells that are induced during early stages of ADJ-PC-5 tumorigenesis.

scholarly journals In Vitro Biocompatibility and Osteoblast Differentiation of an Injectable Chitosan/Nano-Hydroxyapatite/Collagen Scaffold

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Yan Chen ◽  
Zhi Huang ◽  
Xiaoming Li ◽  
Songjian Li ◽  
Zhilai Zhou ◽  
...  
Keyword(s):  
Collagen Scaffold ◽  
Reaction Cell ◽  
In Vitro Biocompatibility ◽  
In Situ Forming ◽  
Osteogenic Markers ◽  
Polymerase Chain ◽  
Cell Expression

The purpose of this study was to evaluate the in vitro cell biocompatibility of an in situ forming composite consisting of chitosan (CS), nano-hydroxyapatite and collagen (nHAC), which has a complex hierarchical structure similar to natural bone. MC3T3-E1 mouse calvarial preosteoblasts were cultured on the surface of the injectable CS/nHAC and CS scaffold. The proliferations of seeded MC3T3-E1 were investigated for 10 days. Cytotoxicity, cell proliferation, and cell expression of osteogenic markers such as alkaline phosphatase (ALP), type 1 collagen (COL-1), RUNX-2, and osteocalcin (OCN) were examined by biochemical assay and reverse transcription polymerase chain reaction. Cell viability and total cellularity (measured by dsDNA) were similar between the two scaffold groups. However, ALP, COL-1, OCN, and RUNX-2 production were significantly greater when osteoblasts were cultured on CS/nHAC scaffolds. The increase in osteogenic markers production on CS/nHAC scaffolds indicated that these scaffolds were superior to chitosan-only scaffolds in facilitating osteoblast mineralization. These results demonstrate the potential of the CS/nHAC scaffolds to be used in bone tissue engineering.

Angiotensin II type 2 receptor mediates vascular smooth muscle cell apoptosis and antagonizes angiotensin II type 1 receptor action: An in vitro gene transfer study

Life Sciences ◽  
1998 ◽  
Vol 63 (19) ◽  
pp. PL289-PL295 ◽  
Author(s):  
Takehiko Yamada ◽  
Masahiro Akishita ◽  
Matthew J. Pollman ◽  
Gary H. Gibbons ◽  
Victor J. Dzau ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Angiotensin Ii ◽  
Gene Transfer ◽  
Cell Apoptosis ◽  
Receptor Action ◽  
Muscle Cell Apoptosis ◽  
Transfer Study

HIV Type 2 Primary Isolates Induce a Lower Degree of Apoptosis "in Vitro" Compared with HIV Type 1 Primary Isolates

2004 ◽  
Vol 20 (5) ◽  
pp. 507-512 ◽  
Author(s):  
Ana Machuca ◽  
Linna Ding ◽  
Rolf Taffs ◽  
Sherwin Lee ◽  
Owen Wood ◽  
...  
Keyword(s):  
Lower Degree ◽  
Hiv Type 1

Two types of leptin-responsive gastric vagal afferent terminals: an in vitro single-unit study in rats

1997 ◽  
Vol 273 (2) ◽  
pp. R833-R837 ◽  
Author(s):  
Y. H. Wang ◽  
Y. Tache ◽  
A. B. Sheibel ◽  
V. L. Go ◽  
J. Y. Wei
Keyword(s):  
Inhibitory Effect ◽  
Vagal Afferents ◽  
Neural Signals ◽  
Excitatory Effect ◽  
Leptin Sensitivity ◽  
Before And After ◽  
Afferent Terminals

In vitro gastric vagal afferents' (GVAs) unit activities were recorded from the ventral GVA nerve strands in rats. The responsiveness of 16 GVA terminals to close intra-arterial injection of vehicle (0.1 ml), leptin (350 pmol), and cholecystokinin (CCK)-8 (10 pmol) was analyzed to generate a spike count-versus-time histogram. Data of 5-min spike counts before and after each treatment were normalized by dividing the latter by the former. A quotient (Q) > 1 indicates an excitatory effect, Q < 1 indicates an inhibitory effect, and Q close to 1 indicates no effect. Two types of GVA terminals were identified. Type 1 (n = 8) responded to leptin with Q > 1; CCK-8 pretreatment did not consistently alter leptin sensitivity. In contrast, Type 2 (n = 8) responded to leptin with Q < 1 or close to 1, and CCK-8 pretreatment increased the leptin sensitivity so that the terminals responded to subsequent leptin with Q > 1. These data suggest that Type 1 and Type 2 GVA terminals may provide afferent neural signals, which, in turn, will be involved in body weight and food intake control systems, respectively.

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