Guinea-pig Muscle Cells Research Articles

Aktivitas Ramuan Herbal sebagai Antagonis Reseptor H1, Relaksan Otot Polos dan Penghambat Degranulasi Sel Mast sebagai Antiasmatik

Asthma is still become a major health problem worldwide, affected all ages from pediatrics to 
 adults. The severity of the disease vary from mild to severe and leads to the risk of death. The 
 uses of medicinal plants as antiasthmatic have often been conducted by the local community. 
 The present study was conducted in vitro and in vivo to determine the activities of herbs 
 containing of sembung leaves (Blumea balsamifera L.), kemukus seeds (Piper cubeba L.), teki 
 rhizome (Cyperus rotundus L.), and patikan kebo herbs (Euphorbia hirta L.) with certain ratio 
 as an antiasthmatic. The in vitro test was carried out on isolated smooth muscle cells of guinea 
 pig. Histamine was used to stimulate the contraction of smooth muscle cells of guinea pig 
 trachea. The in vivo test was carried out using guinea pigs which sensitized with ovalbumin 
 and administered with the herbs formula. The trachea of guinea pigs were prepared for 
 histopathological examination and stained on toluidine blue. The result revealed that the 
 antiasthmatic herbs of 1, 2, and 3 showed activities as H1 receptor antagonists. The 
 antiasthmatic herbs of 1, 2, and 3 were able to relax the smooth muscle of guinea pig’s trachea 
 that was experiencing contraction, but in lower level compared to theophylline. The
 antiasthmatic herbs formula in this study did not have the activity to inhibit mast cell 
 degranulation.

Relaxant effect of ethanol extract of Carum carvi on dispersed intestinal smooth muscle cells of the guinea pig

The present study investigates the direct effects of Carum carvi L. (Apiaceae) ethanol extract on dispersed intestinal smooth muscle cells (SMC) of guinea pigs. Effects of the plant extract on SMC and of acetylcholine (Ach) on extract pretreated SMC were measured by micrometric scanning technique. Three different extract concentrations (2.5 mg/mL, 250 μg/mL, and 25 μg/mL) were used. Ethanol extract of C. carvi reduced significantly the response of dispersed SMC to Ach. Pretreatment of SMC with the highest concentration of C. carvi ethanol extract (2.5 mg/mL) has significantly inhibited the response of SMC to Ach. The data obtained indicate a dose-dependent inhibition of the contraction induced by Ach. This response may explain, in part, the beneficial effect of caraway in relieving gastrointestinal symptoms associated with dyspepsia.

Studies on the Direct Effects of the Alcohol Extract of Tilia cordata. on Dispersed Intestinal Smooth Muscle Cells of Guinea Pig

The effects of the ethanol extract of Tilia cordata. Miller (Tiliaceae) were studied in vitro. using intestinal smooth muscle cells of guinea pigs dispersed by collagenase. The extract induced a dose-dependent contraction of the dispersed smooth muscle cells. The obtained data indicated a direct effect of the T. cordata. extract on the intestinal smooth muscle cells. In addition, the contractions induced by the extract were inhibited by atropine. These observations indicate involvement of some active constituents, with cholinergic properties, found in the alcohol extract to induce contraction of the intestinal smooth muscle cells via activation of the muscarinic receptors.

Characteristics of Ca2+ Oscillations in Ileal Longitudinal Muscle Cells of Guinea Pig

We studied the mechanisms and characteristics of the spontaneously evoked intracellular Ca2+ changes (Ca2+ oscillations) in ileal longitudinal smooth muscle from guinea pig. Two-dimensional images of Ca2+ oscillations were obtained at 33-ms intervals with a Ca2+-sensitive fluorescence probe, fluo-3 using the intensified CCD camera. Nicardipine (10 −7 M) significantly decreased the maximum level of fluorescence intensity of the Ca2+ oscillations, inhibited the frequency of the oscillations and tended to decrease the basal level of fluorescence intensity. However, tetrodotoxin (3 × 10−7 M) did not affect these oscillations. Phorbol 12,13-dibutyrate (10 −7 M) significantly increased the maximum level of fluorescence intensity and the frequency of Ca2+ oscillations, and it changed them to steady and chronometric Ca2+ oscillations. Cyclopiazonic acid (3 × 10−5 M) also significantly increased the frequency of Ca2+ oscillations. Acetylcholine (10−8 M) increased the basal and maximum level of fluorescence intensity and the frequency of Ca2+ oscillations, and accelerated their onset. The increase of basal level of fluorescence intensity was then decreased by cyclopiazonic acid treatment. These results suggest that the augmentation of Ca2+ oscillations is mainly due to the activation of L-type Ca2+ channels, which is modulated by protein kinase C, and that the emptying of intracellular Ca2+ stores may activate the Ca2+ oscillations mediated through the increase of Ca2+ influx in ileal smooth muscle of guinea pig.

P-552 - Cell-proliferative action of endothelin-1 in cultured bronchial smooth muscle cells of guinea pig

P-552 - Cell-proliferative action of endothelin-1 in cultured bronchial smooth muscle cells of guinea pig

P–592 - Induction of iNOS by endothelin-1 in cultured bronchial smooth muscle cells of guinea pig.

P–592 - Induction of iNOS by endothelin-1 in cultured bronchial smooth muscle cells of guinea pig.

Presence of functional receptors for corticotropin releasing hormone in caecal circular smooth muscle cells of guinea pig.

The presence of specific binding sites for corticotropin releasing hormone (CRH) in caecal circular smooth muscle cells of guinea pig was investigated by binding and pharmacological studies. The specific binding of 125I-CRH to these muscle cells reached an equilibrium after 90 minutes. Several peptides structurally unrelated to CRH did not affect the specific binding of 125I-CRH to these muscle cells. Unlabeled CRH completely inhibited the specific binding of 125I-CRH in a concentration-dependent manner, with an IC50 value of 13.5 nM. A CRH receptor antagonist, alpha-helical CRH (9-41), inhibited the specific binding of 125I-CRH in a concentration-dependent manner with a lower affinity than CRH. In pharmacological study, CRH inhibited the contractile response of these muscle cells to 1 nM cholecystokinin-octapeptide in a concentration-dependent manner, with an IC50 value of 14.1 nM. A CRH receptor antagonist, alpha-helical CRH (9-41), significantly antagonized this inhibitory effect produced by CRH. These results strongly suggest the presence of functional receptors for CRH that mediate relaxation of caecal circular smooth muscle cells of guinea pig.

Direct contractile effect of cholecystokinin octapeptide on caecal circular smooth muscle cells of guinea pig via both CCK-A and CCK-B/gastrin receptors

This study was designed to investigate the participation of cholecystokinin(CCK)-A and/or CCK-B/gastrin receptors in CCK-8-induced contraction of guinea pig caecal circular smooth muscle cells, using a novel selective CCK-A receptor antagonist, (S)-N-[1-(2-fluorophenyl)-3,4,6,7-tetrahydro-4-oxo-pyrrolo-[3,2,1-jk] [1,4]benzodiazepine-3-yl]-1H-indole-2-carboxamide (FK480), and a novel selective CCK-B/gastrin receptor antagonist, (R)-1-[2,3-dihydro-1-(2'-methylphenacyl)-2-oxo-5-phenyl-1H-1, 4-benzodiazepine-3-yl]-3-(3-methylphenyl)urea (YM022). Concentration-response curves for the contractile effect of CCK-8 alone and in the presence of 0.1nM FK480, 0.1 nM YM022, or a combination of 0.1 nM FK480 and 0.1 nM YM022 on isolated smooth muscle cells were determined. In addition, the inhibitory effects of various concentrations of FK480 or YM022 on 1 nM CCK-8-induced contraction were examined. At a concentration of 0.1 nM, both FK480 and YM022 shifted the concentration-response curve for CCK-8 to the right (about 100 times) with the same potency. In addition, a concentration-response curve for a combination of 0.1 nM FK480 and 0.1 nM YM022 was shifted to the right (about 100 times) of the curves for 0.1 nM FK480 alone or 0.1 nM YM022 alone. Both antagonists inhibited 1 nM CCK-8-induced contraction of caecal circular smooth muscle cells in a concentration-dependent manner, with the similar inhibitory potency. A significant inhibition was obtained at a concentration as low as 0.1 nM FK480 and 0.1 nM YM022. This study strongly suggested the presence of both CCK-A and CCK-B/gastrin receptors in caecal circular smooth muscle cells of guinea pig, and that the contractile effect of CCK-8 on these cells was mediated via both of these receptors.

Direct inhibitory effect of corticotropin releasing hormone on isolated caecal circular smooth muscle cells of guinea pig via adenylate cyclase system

Smooth muscle cells isolated separately from the caecal circular smooth muscle layer of the guinea pig were used to investigate whether corticotropin releasing hormone (CRH) can inhibit directly the contraction produced by cholecystokinin octapeptide (CCK-8). In addition, the role of adenylate cyclase and guanylate cyclase in the direct inhibitory effect of CRH was examined. CRH inhibited the contractile response produced by 10 −9M CCK-8 in a concentration-dependent manner, with an IC 50 value of 0.16nM. An inhibitor of particulate guanylate cyclase and an inhibitor of soluble guanylate cyclase had no significant effect of the relaxation produced by CRH. In contrast, an inhibitor of adenylate cyclase and an inhibitor of cAMP-dependent protein kinase significantly inhibited the ralaxation produced by CRH. This is the first report demonstrating the direct inhibitory action of CRH on the isolated caecal smooth muscle cells via adenylate cyclase system.

Direct inhibitory effect of thyrotropin-releasing hormone on isolated cecal circular smooth muscle cells of guinea pig.

Smooth muscle cells isolated from cecal circular smooth muscle of the guinea pig were used to determine whether thyrotropin-releasing hormone (TRH) can inhibit the contractile response produced by 10(-6) M carbachol by exerting a direct action on muscle cells. In addition, the inhibitory effect of 2',5'-dideoxyadenosine (an inhibitor of adenylate cyclase), phorbol 12-myristate 13-acetate (an inhibitor of particulate guanylate cyclase), 6-anilinoquinoline-5,8-quinone (an inhibitor of nitric oxide synthase) on the TRH-induced relaxation of cecal circular smooth muscle cells was examined. TRH inhibited the contractile response produced by 10(-6) M carbachol in a concentration-dependent manner, with an IC50 value of 4 nM, 2',5'-Dideoxyadenosine and phorbol 12-myristate 13-acetate did not have any significant effect on the TRH-induced relaxation. On the other hand, 6-anilinoquinoline-5,8-quinone and N omega-nitro-L-arginine methyl ester significantly inhibited the relaxation produced by TRH. Our findings show that TRH has a direct inhibitory effect on the isolated cecal circular smooth muscle cells via activation of nitric oxide synthase and soluble guanylate cyclase.

Use of Confocal Laser Scanning Microscope in Cytochemistry.

The applications of a confocal laser scanning microscope for imaging fast dynamic changes of the intracellular calcium ion concentration ([Ca2+]i) in the living cell are described. Confocal images enable us to determine the cell-to-cell junction between clustered heart muscle cells of guinea pig and reveal that the high [Ca2+]i can evoke calcium-induced calcium release from the sarcoplasmic reticulum in the neighboring heart muscle cells through the gap junction. In rat peritoneal mast cells, secretagogue-induced calcium signaling initiates at the periphery of the cell and propagates to the nucleus as calcium wave. Nuclear [Ca2+]i is upheld at higher level than cytoplasmic [Ca2+]i for 2min. X-t scan mode with high-temporal resolution provides comprehensive images of the phenomenon. The confocal laser scanning microscope with depth-discriminating ability is a valuable tool to know a sequence of biological event within the living cell.

Voltage-dependent calcium channel current in isolated gallbladder smooth muscle cells of guinea pig

The voltage-dependent Ca2+ current was studied in enzymatically dispersed guinea pig gallbladder smooth muscle cells using the whole cell patch-clamp technique. Depolarizing voltage (V) steps induced an inward current (I) that was carried by Ca2+. The threshold potential was -40 to -30 mV, the maximal current was observed at +10 to +20 mV, and the reversal potential was around +80 mV. I-V curves obtained with holding potentials of -80 and -40 mV were not significantly different. This current had a high sensitivity to dihydropyridine drugs, and the Ba2+ or Sr2+ current was larger than the Ca2+ current. Activation was accelerated by increasing the membrane potential. In general, the time course of decay was well fitted by the sum of two exponentials, but consideration of a third (ultra-slow) decay component was also necessary when the current generated by a 2-s command pulse was analyzed. Superimposition of activation and inactivation curves showed the presence of a significant window current. Carbachol suppressed the Ca2+ current only when the pipette contained a low concentration of ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid. These results show that the L-type Ca2+ current is dominant in gallbladder smooth muscle cells and may contribute to excitation-contraction coupling.

Direct inhibitory effect of neurotensin on isolated gastric smooth muscle cells of guinea pig via the cyclic GMP system.

Smooth muscle cells isolated from the gastric muscle layers of the guinea pig were used to determine whether neurotensin can inhibit the contractile response produced by 10(-6) M carbachol by exerting a direct action on muscle cells. In addition, the inhibitory effect of 2',5'-dideoxyadenosine, an inhibitor of adenylate cyclase, and methylene blue, an inhibitor of guanylate cyclase, on the neurotensin-induced relaxation of gastric smooth muscle cells were examined. Neurotensin inhibited the contractile response produced by carbachol in a dose-dependent manner, with an IC50 value of 5 nM. 2',5'-Dideoxyadenosine did not have any significant effect on the neurotensin-induced relaxation. On the other hand, methylene blue significantly inhibited the relaxation produced by neurotensin. These results strongly suggest that the action of neurotensin is mediated by cyclic GMP.

Effects of antiprogesterones on myometrial cell-to-cell coupling in pregnant guinea pigs.

We used intracellular microelectrodes to investigate the effects of the antiprogesterone (AP) compounds RU 486 and ZK 299 on cell-to-cell coupling in the guinea pig myometrium during pregnancy. The input resistance (Ro) of myometrial cells was high in nonpregnant tissues (44.6 +/- 6.39 M omega), but decreased by midgestation (Day 44 or 45 of gestation; 22.9 +/- 3.17 M omega), and was lowest at term (between 17.7 +/- 2.90 m omega and 13.1 +/- 4.34 M omega on Days 59-69). Treatment with the AP RU 486 or ZK 299 in three groups of midgestational animals reduced Ro to a similar level within 24 h. Lucifer Yellow (LY) was injected into smooth muscle cells as a direct but qualitative measure of metabolic coupling. In term and AP-treated animals, LY spread rapidly to neighboring cells within 60 sec, but little spread occurred in midgestational control tissues and no spread was seen even after 10 min in nonpregnant tissues. This correlation of decreased Ro (implying increased electrical coupling) with the development of extensive spread of LY indicates increased electrical and metabolical coupling between myometrial cells during labor. These data show that myometrial smooth muscle cells of guinea pigs are moderately well coupled before the onset of labor, and the coupling increases further, just prior to spontaneous delivery or due to treatment with APs. These events may be required for synchronizing and coordinating the electrical, metabolic, and contractile activity of labor.

Studies on the contractile mechanism of isolated gastric smooth muscle cells of guinea pig

Studies on the contractile mechanism of isolated gastric smooth muscle cells of guinea pig

Identification of muscarinic M2 receptors on single muscle cells of the human and guinea pig intestine

Muscle cells were isolated from the longitudinal muscle layer of guinea pig and human jejunum and used to identify the muscarinic receptor subtype (M1 or M2) that mediates contraction. Single muscle cells were anchored to the ceiling of a minichamber and their contraction was measured in response to acetylcholine, alone and in combination with three muscarinic antagonists: atropine, 4-diphenylacetoxy-N-methylpiperidine methiodide (4-DAMP), and pirenzepine. Estimates of the inhibitory dissociation constants (Ki) were closely similar in human and guinea pig muscle cells (atropine 2.5–5 × 10−11 M. 4-DAMP 1.9–2.9 × 10 −10 M, and pirenzepine 8.2–9.5 × 10 −8 M). Thus, pirenzepine, a preferential M1 antagonist, was 1900–3280 times less potent than atropine and 279–500 times less potent than 4-DAMP. Comparative measurements on longitudinal muscle strips from guinea pig jejunum confirmed the greater potency of atropine and 4-DAMP relative to pirenzepine. Inactivation of muscarinic receptors on single muscle cells with dibenamine showed that only a small fraction of receptors was responsible for the response to acetylcholine. It was concluded that intestinal muscle cells contain a large reservoir of muscarinic M2 receptors that exhibit considerable spareness and heterogeneity.

Source of activator calcium in isolated guinea pig and human gastric muscle cells

The source of Ca2+ responsible for contraction was examined in suspensions of smooth muscle cells and in perfused single muscle cells from guinea pig and human stomach. In both preparations removal of Ca2+ from the medium or addition of the Ca2+ channel blocker methoxyverapamil had no effect on the contractile response to various agonists, including cholecystokinin octapeptide (CCK-8) and acetylcholine, but inhibited the response to high extracellular K+ by 76-82%. Repeated stimulation of guinea pig or human single muscle cells in Ca2+-free medium, or in the presence of methoxyverapamil caused a progressive decrease and eventual abolition of contractile response; response was restored on restitution of Ca2+ to the medium or elimination of methoxyverapamil. Measurement of 45Ca2+ content in guinea pig muscle cells showed that CCK-8 had no effect on the rate of Ca2+ influx but increased the rate of Ca2+ efflux transiently by sixfold. Net peak efflux coincided with the time of peak contraction and was stoichiometrically related to the degree of contraction. Equipotent, maximally effective contractile doses of CCK-8, acetylcholine, and methionine-enkephalin caused equivalent degrees of net Ca2+ efflux. The results indicate that contractile agonists cause release of Ca2+ from a depletable intracellular store in gastric muscle cells. The release is accompanied by a dose-dependent increase in Ca2+ efflux and is capable of sustaining an initial maximal contraction. Repeated contractile activity requires influx of Ca2+ from extracellular sources.

Sensitization-induced sodium influx in airway smooth muscle cells of guinea pigs

Airway smooth muscle (ASM) preparations isolated from Camm-Hartley male guinea pigs were passively in vitro sensitized using Austen's technique. During this sensitization, cells were frequently penetrated with glass microelectrodes (a resistance of 80–90 MΩ) for a period of 120 min. Simultaneously, changes in the isometric force of ASM preparations were also monitored. It was found that: (1) administration of serum (1:10 dilution) from sensitized animals caused a depolarization of ASM cells (−52.3 ± 0.7 mV), achieving a peak at 4 min, followed by slow sustained hyperpolarization reaching a steady state after 15 min; (Resulting resting membrane potential of ASM cells was −60.0 ± 0.7 mV); (2) in the presence of ouabain (10 −5 M), the development of hyperpolarization of ASM cells was completely inhibited; (3) replacement of Na + with choline chloride or lithium chloride partially inhibited the development of depolarization of ASM cells; (4) in the presence of specific sodium entry blocker, amiloride the sensitization-caused depolarization was abolished; (5) the presence of choline chloride, lithium chloride or amiloride in the experimental medium completely inhibited the contractile response of sensitized tissues to a specific antigen; (6) response of ASM preparations to a specific antigen was absent during depolarization of ASM cells, but was always present during their hyperpolarization. It is concluded that in vitro passive sensitization leads to the interaction of serum specific antibodies with the membrane of airway smooth muscle cells so that permeability of membrane for Na + is increased (transient depolarization) followed by the activation of electrogenic Na +-pump (sustained hyperpolarization). These events seem to determine the contractile response of sensitized ASM cells to a specific antigen.

Cytochemical demonstration of guanylate cyclase activity in cardiac muscle. Preferential localization at sarcolemma and junctional sarcoplasmic reticulum.

The localization of guanylate cyclase activity was cytochemically studied in heart tissue from guinea pig and pigeon. The method, based on a lead precipitation technique with GPPNHP as the substrate, was tested by quantitative biochemical analysis. The data obtained showed that in heart homogenates GPPNHP is an acceptable substrate for guanylate cyclase. The guanylate cyclase activity of glutaraldehyde prefixed heart tissue was also measured in the presence of 2 mM lead nitrate, in 30% of the untreated control hearts. The residual guanylate cyclase responded to the addition of sodium nitroprusside with a 7-fold increase in its activity. Furthermore, the guanylate cyclase requirement for Mn2+ ions was so changed by this activator that Mg2+ was as active as Mn2+. In heart muscle cells of guinea pigs and pigeons the plasma membrane of the sarcolemma and the junctional sarcoplasmic reticulum are the precipitation sites of the reaction product. In guinea pig hearts the T-tubule membranes were likewise covered with precipitates. Sodium nitroprusside stimulation of guanylate cyclase activity was indicated by increased precipitation and by shortening of the incubation time.

Induction of lipid droplet accumulation in cardiac muscle cells of guinea pigs and mice: an analysis of the effects of reserpine and fasting.

AbstractReserpine has been demonstrated in previous studies to induce the accumulation of lipid droplets in ventricular cardiac muscle cells of bats and this effect has been attributed to mediation by the sympathetic nervous system. The present study was done to evaluate the species specificity of this action of the drug. Reserpine caused lipid droplet accumulation in cardiocytes of guinea pigs and mice. However, in contrast to the action of the drug in bats, this action of reserpine in guinea pigs and mice could not be antagonized by chemical sympathectomy with 6‐hydroxydopamine or by treatment of animals with phenoxybenzamine, atropine or hexamethonium. Like reserpine, fasting for as little as 24 hours induced lipid droplet accumulation in cardiocytes of guinea pigs and mice. This effect also could not be prevented by treatment with 6‐hydroxydopamine indicating that the sympathetic nervous system was not involved in its mediation. Force‐feeding guinea pigs given reserpine prevented the accumulation of lipid droplets normally induced by this drug. It is concluded that the lipid droplets accumulation in the hearts of guinea pigs that follows administration of reserpine is not due to a direct cardiotoxicity of the drug but is secondary to the failure of drug‐treated animals to eat. Since the autonomic nervous system appears to mediate reserpine's cardiotoxicity in bats, the species difference revealed by these experiments probably results from an underlying physiological difference in the nervous systems of these animals.