Taenia Caeci Research Articles

Effects of simultaneous treatment with PMX-DHP and sivelestat on endotoxaemia in conscious guinea pigs

Using an endotoxaemia model in conscious guinea pigs, we previously reported that polymyxin B immobilized fiber-direct hemoperfusion (PMX-DHP) or administration of sivelestat are effective treatments for sepsis. In the present study, we investigated whether simultaneous treatment with PMX-DHP and sivelestat sodium was more effective than either treatment alone for sepsis. Measurements examined included intestinal paralysis, blood pressure, serum HMGB1 level and survival rate. Colonic motion was monitored continuously by telemetry using a transducer attached to the taenia caecum, while blood pressure was monitored with a carotid artery catheter. The guinea pigs were divided into 4 groups and lipopolysaccharide (LPS) was administered to all animals. The control group received only LPS. The remaining three groups received PMX treatment for 2 hours, sivelestat sodium administration for 2 hours or simultaneous PMX and sivelestat treatment for 2 hours. In the control group, decreased colonic muscle tension and arterial pressure, and increased serum HMGB1 levels were observed and all animals died within 30 hours. In the PMX-DHP treated group, the decreases in colonic tension and arterial pressure were less severe than for the control group and the survival rate was higher than the control group, but serum HMGB1 levels were not significantly different. In the sivelestat group, decreases in colonic tension and arterial pressure were not significantly different with the control group, but serum HMGB1 levels were lower than in the control group. Simultaneous treatment with both PMX-DHP and sivelestat sodium did not exhibit synergistic effects for the treatment of LPS- induced endotoxaemia and mortality. PMX-DHP was effective at treating sepsis induced by administration of a high dose of LPS in guinea pigs, but simultaneous administration of sivelestat sodium did not augment the efficacy of PMX-DHP treatment.

Measurement of Spontaneous Oscillatory Magnetic Field of Guinea-Pig Smooth Muscle Preparation Using Pico-Tesla Resolution Amorphous Wire Magneto-Impedance Sensor

New measured results of spontaneous oscillatory bio-magnetic field generated from preparations of guinea-pig smooth muscle tissue are presented in this paper using the pico-Tesla MI sensor. It is confirmed that the changes in the bio-magnetic field activity precisely synchronized with extracellular electric activity for stomach musculature of the guinea-pig. It is, however, noteworthy that these two activities provide different biological information. A phase lag of around 2 s of the magnetic signal pulse against the extracellular electric signal pulse is newly found. It is also shown that Ca2+ channel activity of the smooth muscle tissue (taenia caeci) can be evaluated using the MI sensor. Both electric and magnetic activities depend on the functionality of the living tissues. Therefore, the pico-Tesla MI sensor has the potential for non-invasive detection use in wide range of biology and medicine, including non-invasive evaluation use of the stem cells development.

Myostimulating effect of <i>Sesamum radiatum</i> aqueous leaf extract in isolated guinea-pig <i>Tainia caeci</i> contractile activity

This study was carried to examine the effects of the aqueous leaf extract of Sesamum radiatum, a laxative plant on the contractile activity of Taenia caeci, an intestinal smooth muscle. Strips of Taenia caeci were rapidly removed from guinea-pig and were suspended between two L-shaped stainless steel hooks in a 10 ml organ bath with Mac Ewen solution. The isometric contractile force of the Taenia caeci strips were recorded by using a strain gauge. S. radiatum aqueous leaf extract (ESera) is a spasmogenic substance. This myostimulant effect is characterized by the increase of the rhythm and the amplitude of isolated guinea-pig Taenia caeci smooth muscle in normal solution and by the development of contracture in modified solution and in solution without calcium. A similar effect was observed with ACh which caused a graded increase of the contractile activity of Taenia caeci. The effects induced by ESera and ACh were reversed in the presence of atropine. The spasmogenic effect induced by ESera could justify partially the use of S. radiatum as laxative in traditional medicine.

Pulse-driven magnetoimpedance sensor detection of biomagnetic fields in musculatures with spontaneous electric activity

We measured biomagnetic fields in musculatures with spontaneous electric activity using a pulse-driven magnetoimpedance (PMI) sensor with the sensitivity improved toward a pico-Tesla (pT) level. Due to the sufficiently short operation interval of 1 μs, this magnetic sensor enabled quasi-real time recordings of the magnetic field for biological electric activity. Isolated small musculatures from the guinea-pig stomach, taenia caeci, portal vein and urinary bladder were incubated in an organ bath at a body temperature. The improved PMI sensor mounted approximately 1 mm below the preparations detected oscillatory magnetic fields reflecting spontaneous electric activities of musculature preparations. In the taenia caeci, application of tetraethyl ammonium (TEA), a K + channel blocker, significantly enhanced the magnetic activity estimated by histogram analysis. Also, in some musculature preparations, simultaneous measurements with electric activity revealed that the observed magnetic activities were attributed to biological electric activity. PMI technology is promising for applications in biology and medicine.

Influence of pyridylisatogen tosylate on contractions produced by ATP and by purinergic stimulation in the terminal ileum of the guinea-pig.

2-2'Pyridylisatogen tosylate (PIT), which antagonizes the inhibitory action of ATP in the taenia caeci, did not antagonize the excitatory effects of exogenous ATP and of purinergic stimulation of the terminal guinea-pig ileum. PIT (0-5--2-5 muM) potentiated the ATP-induced contractions and also the contractions produced by potassium chloride, though the potentiation could not be related to the dose in every experiment. The responses to noradrenaline, adrenaline and histamine were slightly inhibited. PIT also potentiated the contractions produced by electrical stimulation of intramural purinergic nerves when either an alternate or uniform stimulation pattern was used. The present results in which the preparation is contracted by ATP are opposite to those obtained with PIT on the taenia caeci, which is relaxed by ATP. This raises a question of duality or plurality of receptors for ATP.

Depressant action of oxybutynin on the contractility of intestinal and urinary tract smooth muscle.

Experiments were carried out in-vitro using segments of guinea-pig ileum, taenia caeci, ureter and detrusor. In the ileum, oxybutynin (30, 100 nM) competitively antagonized acetylcholine-induced contractions but did not alter those induced by histamine. Higher concentrations of oxybutynin (up to 10 microM) induced a non-competitive depression of responses to both agonists and caused a parallel shift to the right of the Ca2+-induced contractions in taenia caeci strips bathed in a Ca2+-free, high-K+ medium. In the ureter, oxybutynin (1-10 microM) impaired rhythmic muscular contractions in normal medium and after CaCl2 addition in Ca2+-free medium. Similarly to verapamil (10, 30 microM), oxybutynin (10, 30 microM) depressed both the cholinergic and non-adrenergic, non-cholinergic components of the electrically-induced contractions of detrusor strips. It is concluded that oxybutynin has anticholinergic properties and, at higher concentrations, exerts a direct spasmolytic activity possibly mediated by blockade of the transmembrane Ca2+ fluxes responsible for smooth muscle contraction.

Differentiation of calcium antagonists with respect to their effects in normal and skinned taenia caeci preparations

In taenia preparations, depolarized by a K+-rich medium, Ca2+ caused contraction and cinnarizine (0.4-100 microM), trifluoperazine (2-100 microM) and verapamil (0.02-10 microM) caused concentration-dependent antagonism of Ca2+, displacing the Ca2+ log concentration-effect curve to the right and depressing the maximal response. Equieffective (IC75) antispasmogenic concentrations were selected. The antispasmogenic effects of verapamil were readily offset by removing the drug from the bathing fluid but those of the other drugs were not. The calcium antagonists (antispasmogenic IC75) were then tested for spasmolytic activity in tissues generating tension in response to the EC80 of Ca2+. Verapamil was more effective in producing spasmolysis than cinnarazine or trifluoperazine. In skinned taenia preparations, verapamil (100 microM) did not inhibit Ca2+-induced contractions. High concentrations of cinnarizine (100 microM) and trifluoperazine (100 microM) inhibited Ca2+-induced activation of the contractile proteins. However, antispasmogenic IC75s from intact taenia were not able to produce this effect on skinned preparations. It is concluded that there are differences between calcium antagonists. The action of verapamil on intact taenia is mainly exerted on the plasma membrane. Cinnarizine and trifluoperazine act both on the plasma membrane and upon the intracellular contractile machinery.

Dilazep: an inhibitor of adenosine uptake with intrinsic calcium antagonistic properties.

Concentrations of dilazep which were ineffective in altering the muscular tone of the guinea-pig taenia caeci (0.03, 0.3 microM) or the phasic mechanical activity of the rabbit proximal ileum (0.03 microM) markedly potentiated the inhibitory action of adenosine on both these parameters. Dilazep, 0.3 microM or greater, dose-dependently inhibited the mechanical activity of the proximal ileum. This inhibitory action was probably mediated by more than one mechanism, as shown by the fact that theophylline (50, 100 microM) antagonized the effect at lower dilazep concentrations (up to 3 microM) leaving essentially unchanged the response to higher concentrations (6, 10 microM). Similarly, the responses to low doses of dilazep were reduced after desensitization of the organ to adenosine, whilst the responses to higher doses were unaffected by this procedure. In a Ca2+-free, high-K+ medium, dilazep (1-10 microM) caused a parallel shift to the right of the Ca2+-induced contractions of the guinea-pig taenia caeci. Adenosine showed only slight Ca2+-antagonistic properties within the mM range of concentrations. These findings suggest that, at the higher concentration tested, dilazep exhibits Ca2+-antagonistic properties unrelated to its adenosine-mediated mode of action.

Non-competitive spasmolytics as antagonists of Ca++-induced smooth muscle contraction.

Abstract The spasmolytic drugs papaverine, phenpropamine, Cxn 2 (1-methyl-amino-3,3,5-trimethylcyclohexane), khellin, cyclandelate, magnesium chloride, cocaine, 2,4-dinitrophenol and KCN antagonize various types of spasmogens, such as acetylcholine or histamine, non-competitively. They are assumed to act at some level in the excitation-contraction process common to the various spasmogens. Ca++ is essential for the induction of a contraction by the spasmogens. In the non-competitive action of some spasmolytics, Ca++ is postulated to be involved. To detect possible differences in their mechanism of action the various spasmolytics were tested against Ca++ acting as a pseudo-spasmogen on the K+-primed taenia caeci of the guineapig in a Ca++-free medium. Although different mechanisms of action for the various spasmolytics are to be expected, they all behaved similarly with respect to Ca++ in that they all caused a parallel shift in the log dose-response curve of Ca++ to higher concentrations.

Nerve-mediated non-adrenergic inhibitory responses of guinea-pig taenia caeci: further evidence of depression by morphine.

Nerve-mediated non-adrenergic inhibitory responses of guinea-pig taenia caeci: further evidence of depression by morphine.

Interactions of muscarinic drugs with their receptors in single cells of guinea-pig taenia caecum.

Single cells were prepared from the guinea-pig taenia caecum and used for the study of drug-receptor interactions. The cells showed a graded response to carbachol, the dose response curve being shifted in a parallel fashion by atropine, indicating a competitive antagonism. The pA2-value of atropine was in agreement with that estimated using the intact tissue. [3H]QNB (quinuclidinyl benzilate) combined with the single cells, the Scatchard plot yielding a straight line. The dissociation constant of QNB was similar to values estimated in other membrane preparations. The apparent dissociation constants of cholinergic drugs estimated from inhibition of the specific binding of [3H]QNB (0.20 nM) to the single cells by the cholinergic drugs were also in agreement with the values in other membrane preparations. The results indicate that the single smooth muscle cells are useful for the study of drug-receptor interactions.

The failure of morphine to depress selectively non-adrenergic neural inhibition of the guinea-pig taenia caeci.

The failure of morphine to depress selectively non-adrenergic neural inhibition of the guinea-pig taenia caeci.

Three-dimensional demonstration of the interstitial cells of Cajal associated with the submucosal plexus in guinea-pig caecum

The guinea-pig caecum was studied by using immunohistochemistry for Kit receptors and nerves to clarify whether interstitial cells of Cajal (ICC) were localized in association with the submucosal plexus (ICC-SP). A large area of the guinea-pig caecum was nearly devoid of longitudinal muscles, because they were concentrated into three bundles of the taenia caeci (coli) and this allowed clear observation of the myenteric and submucosal plexus as separate networks in whole-mount stretch preparations. The myenteric plexus was observed as a loose polygonal network consisting in elongated ganglia and long connecting nerve strands, whereas the submucosal plexus was identified as smaller ovoid ganglia connected to much thinner nerve strands in different tissue layers. Three-dimensional reconstruction of confocal images revealed multipolar-shaped ICC-SP located around the submucosal ganglion in a basket formation. Bipolar ICC-SP were also observed along the connecting nerve strands of the submucosal plexus. The functional involvement of ICC-SP in mucosal activity is discussed in relation to fluid transportation. This three-dimensional study of ICC-SP thus provides a candidate for the most suitable material available for functional experiments examining the physiological significance of ICC-SP.

Hydrogen sulphide inhibits carbachol-induced contractile responses in β-escin permeabilized guinea-pig taenia caecum

Hydrogen sulphide (H 2S) is an endogenous mediator producing a potent relaxation response in vascular and non-vascular smooth muscles. While ATP-sensitive potassium channels are mainly involved in this relaxant effect in vascular smooth muscle, the mechanism in other smooth muscles has not been revealed yet. In the present study, we investigated how H 2S relaxes non-vascular smooth muscle by using intact and β-escin permeabilized guinea-pig taenia caecum. In intact tissues, concentration-dependent relaxation response to H 2S donor NaHS in carbachol-precontracted preparations did not change in the presence of a K ATP channel blocker glibenclamide, adenylate cyclase inhibitor SQ-22536, guanylate cyclase inhibitor ODQ, protein kinase A inhibitor KT-5720, protein kinase C inhibitor H-7, tetrodotoxin, apamin/charybdotoxin, NOS inhibitor L-NAME and cyclooxygenase inhibitor indomethacin. We then studied how H 2S affected carbachol- or Ca 2+-induced contractions in permeabilized tissues. When Ca 2+ was clamped to a constant value ( pCa6), a further contraction could be elicited by carbachol that was decreased by NaHS. This decrease in contraction was reversed by catalase but not by superoxide dismutase or N-acetyl cysteine. The sarcoplasmic reticulum Ca 2+-ATPase pump inhibitor, cyclopiazonic acid, also decreased the carbachol-induced contraction that was further inhibited by NaHS. Mitochondrial proton pump inhibitor carbonyl cyanide p-trifluromethoxyphenylhydrazone also decreased the carbachol-induced contraction but this was not additionally changed by NaHS. The carbachol-induced Ca 2+ sensitization, calcium concentration–response curves, IP 3- and caffeine-induced contractions were not affected by NaHS. In conclusion, we propose that hydrogen peroxide and mitochondria may have a role in H 2S-induced relaxation response in taenia caecum.

TPC2 Proteins Mediate Nicotinic Acid Adenine Dinucleotide Phosphate (NAADP)- and Agonist-evoked Contractions of Smooth Muscle

Agonists such as those acting at muscarinic receptors are thought to induce contraction of smooth muscle primarily through inositol 1,4,5-trisphosphate production and release of Ca2+ from sarcoplasmic reticulum. However, the additional Ca2+-mobilizing messengers cyclic adenosine diphosphate ribose (cADPR) and nicotinic acid adenine dinucleotide phosphate (NAADP) may also be involved in this process, the former acting on the sarcoplasmic reticulum, the latter acting on lysosome-related organelles. In this study, we provide the first systematic analysis of the capacity of inositol 1,4,5-trisphosphate, cADPR, and NAADP to cause contraction in smooth muscle. Using permeabilized guinea pig detrusor and taenia caecum, we show that all three Ca2+-mobilizing messengers cause contractions in both types of smooth muscle. We demonstrate that cADPR and NAADP play differential roles in mediating contraction in response to muscarinic receptor activation, with a sizeable role for NAADP and acidic calcium stores in detrusor muscle but not in taenia caecum, underscoring the heterogeneity of smooth muscle signal transduction systems. Two-pore channel proteins (TPCs) have recently been shown to be key components of the NAADP receptor. We show that contractile responses to NAADP were completely abolished, and agonist-evoked contractions were reduced and now became independent of acidic calcium stores in Tpcn2−/− mouse detrusor smooth muscle. Our findings provide the first evidence that TPC proteins mediate a key NAADP-regulated tissue response brought about by agonist activation of a cell surface receptor.

Histamine Develops Homologous Desensitization under Ca<sup>2+</sup>-free Conditions with Increase in Basal Tone in Smooth Muscle of Guinea Pig Taenia Caeci

Histamine regulates a variety of physiological or pathophysiological processes via the activation of G(q/11) protein-coupled and Ca(2+)-mobilizing histamine H(1) receptors, including smooth muscle contraction. We have found that histamine induces progression from heterologous to homologous desensitization of contraction under normal physiological conditions in smooth muscle of guinea pig taenia caeci. In this study, we characterized the development of histamine-induced desensitization under Ca(2+)-free conditions and we found that histamine developed only a homologous phase of desensitization to histamine with an increase in EC(50) values for histamine and basal tone. In contrast, histamine treatment reduced EC(50) values for a muscarinic agonist, carbachol, and depolarizing high K(+). These results suggest that the failure of excess histamine to induce a normal Ca(2+) response under Ca(2+)-free conditions may lead to homologous desensitization to histamine with apparent hyper-reactivity of smooth muscles to cholinergic and depolarizing stimuli. We estimate that this characteristic of histamine to change smooth muscle contractility may be potentially involved in its physiological and pathophysiological aspects, including histamine-induced allergic conditions, depending on cellular circumstances.

Inhibitory effects of amlexanox on carbachol-induced contractions of rabbit ciliary muscle and guinea-pig taenia caecum.

Instillation of amlexanox, an anti-allergic drug, over a long period improves myopia in some allergy patients and in monkeys. The relaxing effect of amlexanox on persistent contraction of ciliary muscle may be involved in the improvement of myopia. In this study, the mechanism of the noncompetitive inhibition of carbachol-induced contractions by amlexanox (1-100 microM) was investigated in isolated smooth muscle preparations of the rabbit ciliary body and guinea-pig taenia caecum. In ciliary muscles, amlexanox (100 microM) inhibited both the phasic and tonic components of carbachol-induced contractions even in the presence of cyclopiazonic acid (10 microM) where the function of the sarcoplasmic reticulum was impaired, while diltiazem (3.2, 32 microM) did not. In taenia caecum, diltiazem (3.2 microM) slightly inhibited the phasic component and abolished the tonic component of carbachol-induced contractions. Amlexanox also abolished the tonic component, but it did not decrease the 45Ca2+ uptake into taenia caecum smooth muscle cells induced by carbachol. Amlexanox did not increase the cyclic adenosine monophosphate (cyclicAMP) content of ciliary muscles in the presence of 3-isobutyl-1-methylxanthine (10 microM), while forskolin (1 microM) did. Gel-shift assay showed that the inhibition of carbachol-induced contractions by amlexanox was accompanied by a decrease in phosphorylation of the 20-kDa myosin light chain in taenia caecum tissue preparations. Amlexanox had no effect on calmodulin activity, whereas it inhibited phosphorylation of the myosin light chain by purified myosin light-chain kinase from chicken gizzard. These results suggested that amlexanox may not affect either Ca2+ mobilization or calmodulin activity, although it inhibits myosin light-chain kinase, which may inhibit carbachol-induced contraction.

Regulatory mechanism of smooth muscle contraction studied with gelsolin-treated strips of taenia caeci in guinea pig

The potential roles of the regulatory proteins actin, tropomyosin (Tm), and caldesmon (CaD), i.e., the components of the thin filament, in smooth muscle have been extensively studied in several types of smooth muscles. However, controversy remains on the putative physiological significance of these proteins. In this study, we intended to determine the functional roles of Tm and CaD in the regulation of smooth muscle contraction by using a reconstitution system of the thin filaments. At appropriate conditions, the thin (actin) filaments within skinned smooth muscle strips of taenia caeci in guinea pigs could be selectively removed by an actin-severing protein, gelsolin, without irreversible damage to the contractile apparatus, and then the thin filaments were reconstituted with purified components of thin filaments, i.e., actin, Tm, and CaD. We found that the structural remodeling of actin filaments or thin filaments was functionally linked to the Ca(2+)-induced force development and reduction in muscle cross-sectional area (CSA). That is, after the reconstitution of the gelsolin-treated skinned smooth muscle strips with pure actin, the Ca(2+)-dependent force development was partially restored, but the Ca(2+)-induced reduction in CSA occurred once. In contrast, the reconstitution with actin, followed by Tm and CaD, restored not only the force generation but also both its Ca(2+) sensitivity and the reversible Ca(2+)-dependent reduction in CSA. We confirmed that both removal of the thin filaments by gelsolin treatment and reconstitution of the actin (thin) filaments with Tm and CaD caused no significant changes in the level of myosin regulatory light chain phosphorylation. We thus conclude that Tm and CaD are necessary for the full regulation of smooth muscle contraction in addition to the other regulatory systems, including the myosin-linked one.

HISTAMINE‐INDUCED PROGRESSION FROM HETEROLOGOUS TO HOMOLOGOUS DESENSITIZATION OF CONTRACTION IN SMOOTH MUSCLE OF GUINEA‐PIG TAENIA CAECI

1. We have reported previously that, in the smooth muscle of guinea-pig taenia caeci, the development of carbachol-induced desensitization to carbachol and histamine has a similar time-course whereas desensitization to high K(+) is interrupted by sustained resensitization. 2. In the present study, we evaluated the development of histamine-induced desensitization to histamine, carbachol and high K(+) with respect to their regulation by resensitization, and compared it with carbachol-induced desensitization. 3. Desensitization to histamine developed following pretreatment with 10(-5) mol/L histamine for 30 min with a tendency of transient interruption by resensitization at 1 min. In contrast, histamine-induced desensitization to carbachol and high K(+) was transient, peaking at around 15 s and 2 min, respectively, followed by sustained resensitization up to complete restoration within 2 and 10 min, respectively. 4. Thus, in contrast with carbachol, histamine initially induces heterologous desensitization, followed by sustained resensitization to carbachol and high K(+), resulting in selective and sustained homologous desensitization to histamine. 5. Thus, differences in the development of histamine- and carbachol-induced heterologous desensitization/resensitization contribute to the selective regulation of receptor-mediated signal transduction pathways.

Effects of equinatoxin II on isolated guinea pig taenia caeci muscle contractility and intracellular Ca 2+

Equinatoxin II (EqT II) is a ∼20 kDa cytotoxic and cytolytic protein isolated from the sea anemone Actinia equina. When injected intravenously to rats the toxin has been reported to produce a rapid cardiorespiratory arrest. In the present study, we show that EqT II increases the tension of spontaneous contractions and induces long-lasting contracture of guinea pig taenia caeci muscle. In taenia caeci, dissociated smooth muscle cells, microspectrofluorometric measurements, using the Ca 2+ indicator fura-2/AM, revealed that the toxin causes a marked increase in intracellular calcium, provided Ca 2+ is present in the external medium. The increase in intracellular Ca 2+ by EqT II was not blocked or diminished by the calcium channel blocker verapamil. Furthermore, pre-treatment of smooth muscle cells with Ca 2+-ATPase inhibitor thapsigargin, or exposure of the cells to a high K + (75 mM) medium did not prevent EqT II-induced intracellular Ca 2+ increases. Replacement of external sodium by sucrose markedly modified the time course of Ca 2+ signals suggesting the involvement of the Na +/Ca 2+ exchanger in EqT II action. Our results strongly suggest that EqT II-induced increase in intracellular Ca 2+ and muscle tension are both dependent on the ability of EqT II to insert into the membrane and form pores allowing Ca 2+ influx into the cells. To our knowledge this is the first report showing that EqT II causes contraction and contracture of taenia caeci muscles and increases intracellular Ca 2+ in smooth muscle cells.