Leukotriene D4 excitation of rabbit distal colon arises in the region of the muscularis mucosae

1990 ◽  
Vol 259 (5) ◽  
pp. G753-G759
Author(s):  
W. H. Percy ◽  
S. Y. Lee ◽  
M. B. Burton ◽  
T. Tolentino ◽  
R. Burakoff
Keyword(s):  
Muscularis Propria ◽  
Circular Muscle ◽  
Distal Colon ◽  
Muscle Layer ◽  
Mechanical Activity ◽  
Muscularis Mucosae ◽  
Leukotriene D4 ◽  
In Vitro Techniques

We previously have demonstrated in vivo that intra-arterial administration of leukotriene D4 (LTD4) causes increased myoelectric and mechanical activity in the rabbit distal colon. The aim of this study was to use both in vivo and in vitro techniques to try to elucidate the mechanism underlying this effect. In vivo the excitatory response of the rabbit distal colon to LTD4 was abolished by pretreatment with atropine (0.1 mg/kg iv) or hexamethonium (5 mg/kg iv) or the LTD4 receptor antagonist SK&F 102922 (0.8 micrograms/kg ia). In vitro neither the longitudinal nor the circular muscle layer responded to LTD4 (10(-10) to 10(-7) M) with a contractile response. Over the same concentration range, LTD4 caused contractions of the muscularis mucosae that were attenuated by either SK&F 102922 (10(-9) to 10(-7) M) or indomethacin (10(-6) M) but were unaffected by atropine (10(-6) M), pyrilamine (10(-6) M), or tetrodotoxin (10(-6) M). Full thickness segments of longitudinal muscle, circular muscle, and muscularis mucosae did not contract to LTD4. These data imply that LTD4-induced excitation of the rabbit distal colon in vivo arises as a result of the excitation of LTD4 receptors in the region of the muscularis mucosae and that this leads ultimately to the release of acetylcholine onto the muscularis propria. It is proposed that one possible mechanism leading to the latter effect is an increased excitability of intrinsic nerves resulting from a prostaglandin-induced depression of norepinephrine release from nerves impinging on the submucosal plexus.

Studies in vivo and in vitro on effects of PGE2 on colonic motility in rabbits

1992 ◽  
Vol 262 (1) ◽  
pp. G23-G29 ◽  
Author(s):  
R. Burakoff ◽  
W. H. Percy
Keyword(s):  
Colonic Motility ◽  
Circular Muscle ◽  
Distal Colon ◽  
Muscle Layer ◽  
Distal Region ◽  
Mechanical Activity ◽  
Experimental Conditions ◽  
Motor Effects

Prostaglandins (PG) of the E series are synthesized throughout the gastrointestinal tract, and their elevated levels have been reported in many diarrheal states, including inflammatory bowel disease. It is already known that PGE2 has region-specific and muscle layer-specific effects in different areas of the intestine. The aim of this study was to evaluate possible dose-related motor effects of PGE2 on rabbit proximal and distal colon both in vivo and in vitro. We found that, in the proximal colon in vivo, PGE2 caused inhibition of myoelectric and mechanical activity at low doses but at higher doses caused marked excitation. Under the same experimental conditions, PGE2 caused only excitation in the distal colon, a phenomenon associated with an increase in antegrade contractions and diarrhea. In vitro, PGE2 caused excitation of both proximal and distal colonic longitudinal muscle and relaxation of the circular muscle. Its actions, however, were much more pronounced in the distal region. It is concluded that PGE2 has profound effects on colonic motility that are concentration dependent and that differ with the region of the colon under study. Furthermore, the evidence also suggests that elevated PGE2 levels in disease states may play a significant role in abnormal colonic motility and may facilitate the onset of diarrhea.

Myogenic mechanism for peristalsis in the cat esophagus

1999 ◽  
Vol 277 (2) ◽  
pp. G306-G313 ◽  
Author(s):  
Harold G. Preiksaitis ◽  
Nicholas E. Diamant
Keyword(s):  
Muscle Contraction ◽  
Slow Wave ◽  
Circular Muscle ◽  
Smooth Muscle Contraction ◽  
Slow Waves ◽  
Mechanical Activity ◽  
Control Mechanisms ◽  
Slow Wave Oscillations

A myogenic control system (MCS) is a fundamental determinant of peristalsis in the stomach, small bowel, and colon. In the esophagus, attention has focused on neuronal control, the potential for a MCS receiving less attention. The myogenic properties of the cat esophagus were studied in vitro with and without nerves blocked by 1 μM TTX. Muscle contraction was recorded, while electrical activity was monitored by suction electrodes. Spontaneous, nonperistaltic, electrical, and mechanical activity was seen in the longitudinal muscle and persisted after TTX. Spontaneous circular muscle activity was minimal, and peristalsis was not observed without pharmacological activation. Direct electrical stimulation (ES) in the presence of bethanechol or tetraethylammonium chloride (TEA) produced slow-wave oscillations and spike potentials accompanying smooth muscle contraction that progressed along the esophagus. Increased concentrations of either drug in the presence of TTX produced slow waves and spike discharges, accompanied by peristalsis in 5 of 8 TEA- and 2 of 11 bethanechol-stimulated preparations without ES. Depolarization of the muscle by increasing K+ concentration also produced slow waves but no peristalsis. We conclude that the MCS in the esophagus requires specific activation and is manifest by slow-wave oscillations of the membrane potential, which appear to be necessary, but are not sufficient for myogenic peristalsis. In vivo, additional control mechanisms are likely supplied by nerves.

In vitro model of acute esophagitis in the cat

2005 ◽  
Vol 289 (5) ◽  
pp. G860-G869 ◽  
Author(s):  
Ling Cheng ◽  
Weibiao Cao ◽  
Claudio Fiocchi ◽  
Jose Behar ◽  
Piero Biancani ◽  
...  
Keyword(s):  
In Vitro Model ◽  
Circular Muscle ◽  
Muscle Layer ◽  
Normal Mucosa ◽  
Esophageal Mucosa ◽  
Acute Esophagitis ◽  
Vitro Model ◽  
Esophageal Contraction

We have shown that IL-1β and IL-6, possibly originating from the mucosa in response to injury, inhibit neurally mediated contraction of esophageal circular muscle but do not affect ACh-induced contraction, reproducing the effect of experimental esophagitis on esophageal contraction. To examine the interaction of mucosa and circular muscle in inflammation, we examined the effect of HCl on in vitro esophageal mucosa and circular muscle. Circular muscle strips, when directly exposed to HCl, contracted normally. However, when circular muscle strips were exposed to supernatants of mucosa incubated in HCl (2–3 h, pH 5.8), contraction decreased, and the inhibition was partially reversed by an IL-6 antibody. Supernatants from the mucosa of animals with in vivo-induced acute esophagitis (AE) similarly reduced contraction. IL-6 levels were higher in mucosal tissue from AE animals than in control mucosa and in AE mucosa supernatants than in normal mucosa supernatants. IL-6 levels increased significantly in normal mucosa and supernatants in response to HCl, suggesting increased production and release of IL-6 by the mucosa. IL-6 increased H2O2 levels in the circular muscle layer but not in mucosa. Exposure of the mucosa to HCl caused IL-1β to increase only in the mucosa and not in the supernatant. These data suggest that HCl-induced damage occurs first in the mucosa, leading to the production of IL-1β and IL-6 but not H2O2. IL-1β appears to remain in the mucosa. In contrast, IL-6 is produced and released by the mucosa, eventually resulting in the production of H2O2 by the circular muscle, with this affecting circular muscle contraction.

Neural control of canine colon motor function: studies in vitro

1988 ◽  
Vol 66 (3) ◽  
pp. 359-368 ◽  
Author(s):  
T. Gonda ◽  
E. E. Daniel ◽  
F. Kostolanska ◽  
M. Oki ◽  
J. E. T. Fox
Keyword(s):  
Substance P ◽  
Neural Control ◽  
Circular Muscle ◽  
Distal Colon ◽  
Field Stimulation ◽  
Inhibitory Effects ◽  
Release Of Acetylcholine ◽  
Neural Excitation

The responses of strips of the canine colon to stimulation of intrinsic nerves and to the probable mediators of these nerves were studied in vitro. Studies were carried out using longitudinal and circular muscle strips from proximal and distal colon with field stimulation and addition of agents to the bath. Overall, these and other studies in vivo suggested that acetylcholine was an ubiquitous mediator of neural excitation. Norepinephrine had mixed inhibitory and excitatory effects, the latter only in circular muscle. Inhibitory effects of norepinephrine seemed to be both pre- and post-synaptic but no evidence that it was released by field stimulation was obtained. Substance P had excitatory effects chiefly by release of acetylcholine. It, in addition to norepinephrine, at least in circular muscle, deserves evaluation as the mediator of noncholinergic excitation to high frequency field stimulation. Although vasoactive intestinal peptide sometimes had inhibitory effects, these were incomplete and inconsistent. However, further evaluation of its possible role as a nonadrenergic, noncholinergic inhibitory mediator is required to determine if it is involved as one component in the response. Few qualitative differences existed between responses of various regions of the colon to potential neuromediators, although there were some consistent differences between responses of longitudinal and circular muscle. Some differences existed in responses obtained earlier in vivo and in vitro. In particular, inhibitory effects following excitation by substance P on field stimulation were found only in vivo. Nonadrenergic, noncholinergic inhibitory responses to field stimulation were consistently present only in vitro. These differences have not been explained.

Comparison of the effects of leukotrienes B4 and D4 on distal colonic motility in the rabbit in vivo

1989 ◽  
Vol 257 (6) ◽  
pp. G860-G864 ◽  
Author(s):  
R. Burakoff ◽  
E. Nastos ◽  
S. Won ◽  
W. H. Percy
Keyword(s):  
Contractile Activity ◽  
Colonic Motility ◽  
Distal Colon ◽  
Mechanical Activity ◽  
Excitatory Action ◽  
Potential Frequency ◽  
Small And Large Intestine ◽  
Related Increase

Leukotrienes (LTs) have been shown to contract smooth muscle of the small and large intestine in vitro, and an increased mucosal synthesis of leukotrienes has been reported to occur in ulcerative colitis. The purpose of this study was to evaluate the effects of LTs B4 and D4 on the myoelectric and mechanical activity of the rabbit distal colon in vivo and to determine how these effects were modified by indomethacin. LTB4 had a weak excitatory action on both electrical and mechanical activity but this was not statistically significant; LTD4 on the other hand caused a significant dose-related increase in spike potential frequency and contractile activity. Indomethacin alone (1 mg/kg) had no significant effect on the electrical or mechanical activity of the colon but blocked the effects of subsequently administered LTD4. It is concluded from these data that at least part of the excitatory action of LTD4 results from its causing the synthesis and release of excitatory prostaglandins. However, whereas leukotrienes have the potential to play an important role in modulating colonic motility, it seems most likely that this effect would occur after pathological stimulus rather than in the normal healthy colon.

Neuronal Inhibition Determines the Gastrointestinal Motor State

Physiology ◽  
1996 ◽  
Vol 11 (2) ◽  
pp. 67-71 ◽  
Author(s):  
DS Delbro
Keyword(s):  
Contractile Activity ◽  
Circular Muscle ◽  
Muscle Layer ◽  
Blocking Agent ◽  
Myenteric Neurons ◽  
Circular Muscle Layer ◽  
Neuronal Inhibition ◽  
Gastrointestinal Motor

The nerve-blocking agent tetrodotoxin induces contractile activity of the gut circular muscle, in vitro, and intestinal hypermotility, in vivo. According to an hypothesis put forward more than 20 years ago, the circular muscle layer is tonically suppressed due to spontaneously active myenteric neurons that "drive" inhibitory motoneurons to the muscle.

Morphometrical estimation of fetal heart growth at different gestational ages by In vivo and In vitro techniques

2011 ◽  
Vol 3 (5) ◽  
pp. 491-494
Author(s):  
Dr. Haritha Kumari Nimmagadda ◽  
◽  
Pooja Pant Pooja Pant ◽  
Rajeev Mukhia ◽  
Dr. Aruna Mukherjee
Keyword(s):  
Fetal Heart ◽  
In Vitro Techniques

Hemostatic wound dressings: Predicting their effects by in vitro tests

2019 ◽  
Vol 33 (9) ◽  
pp. 1285-1297 ◽  
Author(s):  
Cornelia Wiegand ◽  
Martin Abel ◽  
Uta-Christina Hipler ◽  
Peter Elsner ◽  
Michael Zieger ◽  
...  
Keyword(s):  
Blood Clot ◽  
Wound Dressings ◽  
In Vitro Tests ◽  
Regenerated Cellulose ◽  
Oxidized Regenerated Cellulose ◽  
Inflammatory Reactions ◽  
In Vitro Techniques ◽  
Cotton Gauze

Background Application of controlled in vitro techniques can be used as a screening tool for the development of new hemostatic agents allowing quantitative assessment of overall hemostatic potential. Materials and methods Several tests were selected to evaluate the efficacy of cotton gauze, collagen, and oxidized regenerated cellulose for enhancing blood clotting, coagulation, and platelet activation. Results Visual inspection of dressings after blood contact proved the formation of blood clots. Scanning electron microscopy demonstrated the adsorption of blood cells and plasma proteins. Significantly enhanced blood clot formation was observed for collagen together with β-thromboglobulin increase and platelet count reduction. Oxidized regenerated cellulose demonstrated slower clotting rates not yielding any thrombin generation; yet, led to significantly increased thrombin-anti-thrombin-III complex levels compared to the other dressings. As hemostyptica ought to function without triggering any adverse events, induction of hemolysis, instigation of inflammatory reactions, and initiation of the innate complement system were also tested. Here, cotton gauze provoked high PMN elastase and elevated SC5b-9 concentrations. Conclusions A range of tests for desired and undesired effects of materials need to be combined to gain some degree of predictability of the in vivo situation. Collagen-based dressings demonstrated the highest hemostyptic properties with lowest adverse reactions whereas gauze did not induce high coagulation activation but rather activated leukocytes and complement.

The Use of the Chorioallantoic Membrane (CAM) of the Embryonic Chick for the Direct Assessment of Implant Toxicity

1985 ◽  
Vol 13 (4) ◽  
pp. 261-266
Author(s):  
P.P. Monro ◽  
D.P. Knight ◽  
W.S. Pringle ◽  
D.M. Fyfe ◽  
J.R. Shearer
Keyword(s):  
Chorioallantoic Membrane ◽  
In Vitro Techniques ◽  
Implant Materials ◽  
Metal Foils ◽  
Complex Interactions ◽  
Cobalt Nickel ◽  
Histological Criteria ◽  
Fluid Environment

The toxicity of implant materials requires investigation prior to clinical use. We have developed a method where materials are directly applied to the chorioallantoic membrane (CAM) of 9-day-old chick embryos and toxicity is assessed using histological criteria. We evaluated the method using metal foils. The number and organisation of fibroblasts seemed to be the most useful criteria for assessing metal toxicity. Differences were greatest after 10 days of culture on the CAM. The method is sensitive enough to enable us to discriminate between the less toxic aluminium and titanium and the highly toxic cobalt, nickel and tungsten. The proposed method has advantages over in vitro techniques which provide an abnormal fluid environment and in which the more complex interactions that are possible between implant materials and tissue in vivo cannot be modelled.

scholarly journals Adipose and Muscle Cell Co-Culture System: A Novel In Vitro Tool to Mimic the In Vivo Cellular Environment

Biology ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 6
Author(s):  
Palaniselvam Kuppusamy ◽  
Dahye Kim ◽  
Ilavenil Soundharrajan ◽  
Inho Hwang ◽  
Ki Choon Choi
Keyword(s):  
Drug Development ◽  
Culture System ◽  
Cell Types ◽  
Culture Cell ◽  
In Vitro Techniques ◽  
Culture Systems ◽  
Complex Interactions ◽  
Cellular Environment

A co-culture system allows researchers to investigate the complex interactions between two cell types under various environments, such as those that promote differentiation and growth as well as those that mimic healthy and diseased states, in vitro. In this paper, we review the most common co-culture systems for myocytes and adipocytes. The in vitro techniques mimic the in vivo environment and are used to investigate the causal relationships between different cell lines. Here, we briefly discuss mono-culture and co-culture cell systems and their applicability to the study of communication between two or more cell types, including adipocytes and myocytes. Also, we provide details about the different types of co-culture systems and their applicability to the study of metabolic disease, drug development, and the role of secretory factors in cell signaling cascades. Therefore, this review provides details about the co-culture systems used to study the complex interactions between adipose and muscle cells in various environments, such as those that promote cell differentiation and growth and those used for drug development.

Sign in / Sign up

Export Citation Format

Share Document