Receptors on smooth muscle cells: characterization by contraction and specific antagonists

1982 ◽  
Vol 242 (4) ◽  
pp. G400-G407 ◽  
Author(s):  
K. N. Bitar ◽  
G. M. Makhlouf
Keyword(s):  
Smooth Muscle ◽  
Guinea Pig ◽  
Smooth Muscle Cells ◽  
Muscle Cells ◽  
Low Doses ◽  
Response Curves ◽  
High Affinity ◽  
Gastric Smooth Muscle ◽  
Dose Dependent ◽  
Cck Receptor Antagonists

Smooth muscle cells were isolated from the stomach of the guinea pig, and the kinetics, stoichiometry, and specificity of contraction in response to the C-terminal octapeptides of cholecystokinin (CCK-OP), gastrin-17, and acetylcholine were examined. All three agonists elicited dose-dependent peak contraction that did not depend on the presence of extra-cellular calcium. The potencies of CCK-OP and gastrin-17 were equal (D50, 10(-11) M) and 10 times greater than the potency of acetylcholine (D50, 10(-10) M). A combination of low doses of acetylcholine and CCK-OP was synergistic; however, its effect did not exceed the maximal responses to either agonists alone or to high extracellular concentrations of calcium. The specificity of the receptors was established by the use of atropine and the two CCK-receptor antagonists dibutyryl cGMP and proglumide. The span of the dose-response curves was wide, suggesting the existence of receptor heterogeneity. It is concluded that gastric smooth muscle cells of the guinea pig possess distinct, high-affinity receptors for CCK-gastrin and acetylcholine; the receptors mediate contraction that is not immediately dependent on the presence of extracellular calcium.

Smooth muscle cells from guinea pig stomach possess high-affinity galanin receptors that mediate relaxation

1994 ◽  
Vol 266 (5) ◽  
pp. G839-G845 ◽  
Author(s):  
Z. F. Gu ◽  
T. K. Pradhan ◽  
D. H. Coy ◽  
R. T. Jensen
Keyword(s):  
Smooth Muscle ◽  
Guinea Pig ◽  
Smooth Muscle Cells ◽  
Muscle Cells ◽  
Maximal Effect ◽  
Dependent Manner ◽  
High Affinity ◽  
Gastric Smooth Muscle ◽  
Guinea Pig Stomach ◽  
Galanin Receptors

Galanin-like immunoactivity occurs in nerves and plexi in muscle layers throughout gastrointestinal tract including the stomach. Galanin can affect gastric emptying and contraction or relaxation of gastric muscle in different species. The aim of this study was to investigate the direct effect of galanin on dispersed gastric smooth muscle cells and to characterize any galanin receptors that mediated any effect. Dispersed gastric smooth muscle cells were prepared from guinea pig stomach by collagenase digestion. Porcine galanin (p-galanin; 1 microM) did not stimulate contraction when present alone; however, p-galanin (1 microM) inhibited carbachol-induced contraction with a half-maximal effect at 7 nM. p-Galanin (1 microM) increased cellular adenosine 3',5'-cyclic monophosphate (cAMP) content by 10 s and caused a maximal increase of 80% over basal. 125I-galanin (porcine) bound to dispersed cells in a time- and temperature-dependent manner. Binding was saturable, reversible, and specific. Binding of 125I-galanin was inhibited almost equally by porcine and rat galanin (Ki = 6-8 nM) but was not inhibited by the galanin-associated peptide [preprogalanin-(108-123)]. The fragment galanin-(1-16) was equally potent to rat galanin; however, the fragment galanin-(9-29) was 56-fold less potent (Ki = 370 nM). Computer analysis demonstrated there were two binding sites for p-galanin on gastric smooth muscle cells, a high-affinity site (Kd = 2.6 nM) with low capacity (Bmax = 175 fmol/mg protein) and a low-affinity site (Kd = 150 nM) with large capacity (Bmax = 3,611 fmol/mg protein).(ABSTRACT TRUNCATED AT 250 WORDS)

Oxytocin-induced changes in single cell K+ currents and smooth muscle contraction of guinea-pig gastric antrum

1997 ◽  
Vol 136 (5) ◽  
pp. 531-538 ◽  
Author(s):  
Dessislava B Duridanova ◽  
Milena D Nedelcheva ◽  
Hristo S Gagov
Keyword(s):  
Smooth Muscle ◽  
Cell Membrane ◽  
Guinea Pig ◽  
Smooth Muscle Cells ◽  
Muscle Cells ◽  
Gastric Antrum ◽  
Dependent Manner ◽  
Response Curves ◽  
Dose Dependent ◽  
In Cells

Abstract To study the effects of oxytocin on both spontaneous phasic contractions and K+ outward currents (IK) of the so-called 'non-target' smooth muscle cells, physiological concentrations of oxytocin ranging between 10−12 mol/l and 10−8 mol/l were applied to smooth muscle preparations and single voltage-clamped cells isolated from the circular layer of the guinea-pig gastric antrum. Oxytocin (10−12mol/l to 10−8 mol/l) suppressed, in a dose-dependent manner, the tetrodotoxin- and atropine-resistant spontaneous phasic contractions and shifted rightward the dose–response curves of 10−7 mol/l charybdotoxin and 10−3mol/l BaCl2. In cells with preloaded intracellular Ca2+ stores, oxytocin (10−12 mol/l to 10−9 mol/l) caused a dose-dependent activation of the charybdotoxin-blockable non-inactivating component of IK (IK(s1)) of single voltage-clamped cells, which was accompanied by hyperpolarization of the cell membranes. 8Lys-vasopressin and 8arg-vasopressin failed to mimic the effects of oxytocin on both contraction and K+ currents. Further, the oxytocin-induced activation of IK(s1) was effectively antagonized by 5× 10−8 mol/l U-73122 or 5× 10−6 mol/l 2-nitro-4-carboxyphenyl N,N-diphenylcarbamate (inhibitors of the cell membrane phospholipase C), as well as by intracellularly applied heparin (selective inhibitor of inositol-1,4,5-trisphosphate (IP3)-induced Ca2+ release channels). In cells incubated in the absence of Ca2+ entry throughout the study, oxytocin (10−9 mol/l) caused a slight and transient increase of IK(s1) amplitudes. Neither ryanodine (10−6 mol/l nor cyclopiazonic acid (10−6 mol/l) were able to restore the IK-activating effect of oxytocin in these cells. The data obtained suggest (i) that selective oxytocin receptors are present on the membranes of guinea-pig antral smooth muscle cells, (ii) that the oxytocin-related relaxation may result from the activation of Ca2+-sensitive K+ conductivity via activation of IP3-induced release of Ca from the submembrane located cisternae of the sarcoplasmic reticulum Ca2+ stores and (iii) in turn, this evokes a non-inactivating component of IK, hyperpolarizing the cell membrane. European Journal of Endocrinology 136 531–538

Motilin receptors on isolated gastric smooth muscle cells

1988 ◽  
Vol 254 (2) ◽  
pp. G210-G216 ◽  
Author(s):  
D. S. Louie ◽  
C. Owyang
Keyword(s):  
Smooth Muscle ◽  
Guinea Pig ◽  
Smooth Muscle Cells ◽  
Dose Response ◽  
Contractile Response ◽  
Muscle Cells ◽  
Maximal Response ◽  
Gastric Smooth Muscle ◽  
Substance P Antagonist ◽  
Dose Dependent

Motilin has a stimulating effect on gastrointestinal motility. The mechanism of its action is not known. Direct and neuronal effects have been postulated. To determine if receptors are present on smooth muscle cells we investigated the effect of synthetic porcine motilin and its interaction with acetylcholine on isolated guinea pig gastric smooth muscle cells. Motilin elicited a dose-dependent contraction of gastric smooth muscle cells. Minimal (8.3 +/- 1.3%) and maximal (33.9 +/- 2.4%) responses were observed at 10(-12) and 10(-6) M, respectively. The ED50 of motilin was 10(-9) M. Acetylcholine also elicited a dose-response muscle contraction with a maximal response observed at 10(-7) M. Atropine (10(-7) M) completely inhibited the maximal response to acetylcholine but did not have any effect on the contractile response to motilin. In addition, dibutyryl guanosine 3',5'-cyclic monophosphate (10(-3) M) and substance P antagonist, spantide (10(-4) M), also did not inhibit the action of motilin. Acetylcholine (10(-11) M) shifted the dose-response curve of motilin to the left by 1.5 log units. The maximal response to the combination of motilin (10(-6) M) and acetylcholine (10(-11) M) was 32 +/- 3.2%, which was similar to the maximal response to motilin alone. It is concluded that distinct motilin and muscarinic receptors are present on guinea pig gastric smooth muscle cells. The interaction between motilin and acetylcholine is additive and not potentiative.

Gastric smooth muscle cells possess two classes of endothelin receptors but only one alters contraction

1994 ◽  
Vol 266 (4) ◽  
pp. G713-G721 ◽  
Author(s):  
Y. Kitsukawa ◽  
Z. F. Gu ◽  
P. Hildebrand ◽  
R. T. Jensen
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Muscle Contraction ◽  
Muscle Cells ◽  
The Other ◽  
Stomach Muscle ◽  
Dependent Manner ◽  
High Affinity ◽  
Gastric Smooth Muscle ◽  
Eta Receptor

Endothelin (ET)-like immunoreactivity and ET binding sites are widely distributed in the gastrointestinal tract, and ET causes contraction of stomach muscle strips. To determine whether ETs could interact with gastric smooth muscle cells directly and alter function, we measured binding of 125I-ET-1, 125I-ET-2, and 125I-ET-3 to dispersed gastric smooth muscle cells from guinea pig and their abilities to alter cell length. Each ligand bound in a time- and temperature-dependent manner, which was specific and saturable. Analysis of the dose-inhibition curves of both ET-1 and ET-3 for binding of each ligand indicated the presence of two classes of receptors, one class (ETA receptor) with a high affinity for ET-1 and ET-2 but a low affinity for ET-3, and the other (ETB receptor) with a high affinity for ET-1, ET-2, and ET-3. The ligands were rapidly internalized by both receptors; however, it was greater with ETA receptors. ET-1 stimulated muscle contraction (50% effective concentration approximately 2 nM), whereas ET-3 did not stimulate contraction or cause relaxation. These results demonstrate that gastric smooth muscle cells possess two classes of ET receptors. One type (ETA) has a high affinity for ET-1 and ET-2 and a low affinity for ET-3, and receptor occupation results in rapid ligand internalization and muscle contraction; the other type (ETB) has a high affinity for ET-1, ET-2, and ET-3, and receptor occupation results in a lesser degree of ligand internalization than the ETA receptor and does not alter contractile behavior.

Direct Inhibitory Effect of Neurotensin on Isolated Gastric Smooth Muscle Cells of Guinea Pig via the Cyclic GMP System

Digestion ◽  
1993 ◽  
Vol 54 (3) ◽  
pp. 135-138
Author(s):  
Yoshiharu Chijiiwa ◽  
Osamu Kawakami ◽  
Tadashi Misawa ◽  
Teppei Kabemura ◽  
Hajime Nawata
Keyword(s):  
Smooth Muscle ◽  
Guinea Pig ◽  
Smooth Muscle Cells ◽  
Cyclic Gmp ◽  
Muscle Cells ◽  
Inhibitory Effect ◽  
Gastric Smooth Muscle ◽  
Direct Inhibitory Effect

Somatostatin receptor subtype 3 mediates the inhibitory action of somatostatin on gastric smooth muscle cells

1995 ◽  
Vol 268 (5) ◽  
pp. G739-G748 ◽  
Author(s):  
Z. F. Gu ◽  
V. D. Corleto ◽  
S. A. Mantey ◽  
D. H. Coy ◽  
P. N. Maton ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Protease Inhibitors ◽  
Somatostatin Receptor ◽  
Muscle Cells ◽  
Receptor Subtype ◽  
Binding Studies ◽  
High Affinity ◽  
Gastric Smooth Muscle ◽  
Subtype 3

Previous functional studies show that somatostatin (SS) interacts with specific receptors to inhibit relaxation in gastric smooth muscle cells. There are no ligand binding studies, and it is unknown which of the five subtypes of SS receptors mediates the action. Dispersed gastric smooth muscle cells from guinea pig bound both 125I-labeled SS-14 and 125I-D-Phe-Cys-Tyr-D-Trp-Lys-Thr-Cys-Nal-NH2 (where Nal indicates N-naphthylalanine) (cyclo-SS-8), a synthetic peptidase-resistant octapeptide SS analogue. SS-28 and SS-14, cyclo-SS-8, and SS analogue D-Phe-Cys-Phe-D-Trp-Lys-Thr-Cys-Thr-ol [SMS-(201-995) (octreotide)] inhibited 125I-cyclo-SS-8 binding with relative potencies of SS-28 = cyclo-SS-8 = SMS-(201-995) (octreotide), and the binding was not affected by the addition of protease inhibitors. SS-14 caused inhibition only in the presence of protease inhibitors. Ligand analysis demonstrated a two-binding-site model. Analysis of the relationship between biological function and binding suggested the high-affinity sites mediated the relaxant action of SS. 5'-Guanylylimidodiphosphate [Gpp-(NH)p] inhibited binding by reducing the affinity of the high-affinity site. Six SS-8 analogues that distinguish SS subtypes showed that 125I-SS-14 bound to somatostatin receptor subtype 3 (SSTR3). The results demonstrated that gastric smooth muscle cells possess distinct receptors for SS of the SSTR3 subtype. Occupation of these sites inhibits relaxation in gastric smooth muscle cells. Modulation between the high- and low- affinity binding states of SSTR3 is at least partially mediated by activation of guanine nucleotide regulatory proteins.

Expression of endothelial nitric oxide synthase in human and rabbit gastrointestinal smooth muscle cells

1998 ◽  
Vol 275 (2) ◽  
pp. G342-G351 ◽  
Author(s):  
B.-Q. Teng ◽  
K. S. Murthy ◽  
J. F. Kuemmerle ◽  
J. R. Grider ◽  
K. Sase ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Smooth Muscle ◽  
Guinea Pig ◽  
Smooth Muscle Cells ◽  
Muscle Cells ◽  
Taenia Coli ◽  
Rt Pcr ◽  
Specific Primers ◽  
Gastric Smooth Muscle ◽  
Oxide Synthase

The aim of this study was to identify the nitric oxide synthase (NOS) isoform expressed in freshly dispersed rabbit gastric smooth muscle cells and in cultured rabbit gastric, human intestinal, and guinea pig taenia coli smooth muscle cells. RT-PCR products of the predicted size (354 bp) were obtained with endothelial NOS (eNOS)-specific primers, but not neuronal NOS (nNOS)- or inducible NOS (iNOS)-specific primers, in all smooth muscle preparations except guinea pig taenia coli. Control RT-PCR studies showed absence of the endothelial markers, platelet endothelial cell adhesion molecule-1 (PECAM-1) and vascular endothelial growth factor receptor (VEGFR), and the interstitial cell marker, c- kit, from cultures of smooth muscle cells. Cloning and sequence analysis showed that the predicted amino acid sequence (117 residues) in rabbit and human smooth muscle cells differed by only one residue from that of human eNOS. Northern blot analysis, using the PCR-generated and cloned eNOS cDNA from rabbits and humans as probes, demonstrated the expression of eNOS mRNA (4.4 kb) in both species. eNOS, but not nNOS or iNOS, transcripts were localized by in situ RT-PCR in single, freshly dispersed rabbit gastric smooth muscle cells; expression was evident in the majority of cells in each preparation. We conclude that eNOS is selectively expressed in rabbit gastric and human intestinal smooth muscle cells. The results confirm functional evidence for the existence of a constitutive NOS in smooth muscle cells of the gut in different species, except for guinea pig taenia coli.

Receptors for mammalian tachykinins on isolated intestinal smooth muscle cells

1985 ◽  
Vol 249 (4) ◽  
pp. G533-G538
Author(s):  
J. C. Souquet ◽  
J. R. Grider ◽  
K. N. Bitar ◽  
G. M. Makhlouf
Keyword(s):  
Smooth Muscle ◽  
Substance P ◽  
Guinea Pig ◽  
Smooth Muscle Cells ◽  
Rank Order ◽  
Circular Muscle ◽  
Muscle Cells ◽  
Receptor Subtype ◽  
Response Curves ◽  
Isolated Cells

The existence of receptors for three mammalian tachykinins, substance P (SP), substance K (SK), and neuromedin K (NK), was examined in smooth muscle cells, isolated separately from the longitudinal and circular muscle layers of guinea pig ileum. Tachykinin receptors capable of mediating contraction were present in muscle cells from both layers. The receptors were selectively blocked by the tachykinin antagonist [D-Pro2, D-Trp7,9]substance P but not by muscarinic, gastrin/cholecystokinin, or opiate antagonists (0.3 nM atropine, 1 mM proglumide, and 0.3 nM naloxone, respectively). The rank order of potency of tachykinins in causing contraction, NK greater than SP greater than SK, was similar in both muscle cell types. The results obtained in isolated muscle cells were closely paralleled by results obtained in intact muscle strips; the main difference was the greater sensitivity of isolated cells to tachykinin agonists (250-fold) and antagonist (210-fold). The inhibitory dissociation constant (Ki) of [D-Pro2, D-Trp7,9]substance P estimated from the displacement of dose-response curves (muscle cells) or from Schild plots (muscle strips) differed minimally or not at all, when either SP or SK was used as agonist, consistent with interaction of the two peptides with the same receptor subtype. The notion of a single receptor subtype in ileal muscle cells of the guinea pig was further supported by the occurrence of complete cross-desensitization between SP and SK in muscle strips.

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