Electrophysiological Analysis of the Gastric Smooth Muscle Fiber of Guinea-pig and Rabbit

CONTEXT AND OBJECTIVE: Smooth muscle fiber has fundamental importance in erection. Alterations in its function or quantity may be associated with erectile dysfunction. The study objective was to assess the proportion of penile smooth muscle fiber in patients with severe erectile dysfunction. DESIGN AND SETTING: Clinical study, in the Sexual Dysfunction Group, Universidade Federal de São Paulo (Unifesp), and in the Anatomy Laboratory, Universidade Estadual do Rio de Janeiro (UERJ). METHODS: Twenty patients with severe erectile dysfunction were selected to form two groups of ten patients: one with normal arterial flow (age range: 44 to 78 years) and the other with altered arterial flow (age range: 38 to 67 years). These groups were compared with a group formed by ten cadavers aged 18 to 25 years that were presumed to have been potent. Quantification of the smooth muscle fibers was done by means of an immunohistochemical study. RESULTS: The proportion of smooth muscle fiber found was 41.15% for the control group. The patients with erectile dysfunction and normal arterial flow presented 27.24% and those with altered arterial flow presented 25.74%; 19 patients presented at least one chronic disease or risk factor for erectile dysfunction, with prominence for diabetes mellitus, systemic arterial hypertension and smoking. CONCLUSION: Among patients with severe erectile dysfunction, the arterial flow on its own does not present interference in the proportion of smooth muscle fiber. The diminution of the proportion of smooth muscle fiber may result from chronic diseases and vascular risk factors.

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Agonist-induced isometric contraction of reconstituted smooth muscle fiber from cultured smooth muscle cells.

The Japanese Journal of Pharmacology ◽

10.1016/s0021-5198(19)34247-7 ◽

1999 ◽

Vol 79 ◽

pp. 56

Author(s):

Kazuhiko Oishi ◽

Yasushi Takeda ◽

Kazuhiro Yamaura ◽

Hiromi Takano-Ohmuro ◽

Masaatsu K. Uchida

Keyword(s):

Smooth Muscle ◽

Smooth Muscle Cells ◽

Muscle Fiber ◽

Isometric Contraction ◽

Muscle Cells ◽

Smooth Muscle Fiber ◽

Cultured Smooth Muscle Cells

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

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.1994.266.5.g839 ◽

1994 ◽

Vol 266 (5) ◽

pp. G839-G845 ◽

Cited By ~ 1

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)

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Functional differences of Na+/Ca2+ exchanger expression in Ca2+ transport system of smooth muscle of guinea pig stomach

Canadian Journal of Physiology and Pharmacology ◽

10.1139/y05-079 ◽

2005 ◽

Vol 83 (8-9) ◽

pp. 791-797 ◽

Cited By ~ 6

Author(s):

Yasushi Sakai ◽

Hiroki Kinoshita ◽

Keiichirou Saitou ◽

Ikuo Homma ◽

Koji Nobe ◽

...

Keyword(s):

Smooth Muscle ◽

Plasma Membrane ◽

Guinea Pig ◽

Gastric Fundus ◽

Relaxation Cycle ◽

Gastric Smooth Muscle ◽

Guinea Pig Stomach ◽

And Function ◽

The Relationship ◽

Ionophore Monensin

The plasma membrane ATP-dependent Ca2+ pump and the Na+/Ca2+ exchanger (NCX) are the major means of Ca2+ extrusion in smooth muscle. However, little is known regarding distribution and function of the NCX in guinea pig gastric smooth muscle. The expression pattern and distribution of NCX isoforms suggest a role as a regulator of Ca2+ transport in cells. Na+ pump inhibition and the consequent to removal of K+ caused gradual contraction in fundus. In contrast, the response was significantly less in antrum. Western blotting analysis revealed that NCX1 and NCX2 are the predominant NCX isoforms expressed in stomach, the former was expressed strongly in antrum, whereas the latter displayed greater expression in fundus. Isolated plasma membrane fractions derived from gastric fundus smooth muscle were also investigated to clarify the relationship between NCX protein expression and function. Na+-dependent Ca2+ uptake increased directly with Ca2+ concentration. Ca2+ uptake in Na+-loaded vesicles was markedly elevated in comparison with K+-loaded vesicles. Additionally, Ca2+ uptake by the Na+- or K+-loaded vesicles was substantially higher in the presence of A23187 than in its absence. The result can be explained based on the assumption that Na+ gradients facilitate downhill movement of Ca2+. Na+-dependent Ca2+ uptake was abolished by the monovalent cationic ionophore, monensin. NaCl enhanced Ca2+ efflux from vesicles, and this efflux was significantly inhibited by gramicidin. Results documented evidence that NCX2 isoform functionally contributes to Ca2+ extrusion and maintenance of contraction-relaxation cycle in gastric fundus smooth muscle.Key words: stomach, smooth muscle, Na+/Ca2+ exchanger (NCX), NCX2.

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Spontaneous electrical activity and associated changes in calcium concentration in guinea‐pig gastric smooth muscle

The Journal of Physiology ◽

10.1113/jphysiol.2001.013306 ◽

2002 ◽

Vol 540 (1) ◽

pp. 249-260 ◽

Cited By ~ 61

Author(s):

Hiroyasu Fukuta ◽

Yoshihiko Kito ◽

Hikaru Suzuki

Keyword(s):

Smooth Muscle ◽

Guinea Pig ◽

Electrical Activity ◽

Calcium Concentration ◽

Spontaneous Electrical Activity ◽

Gastric Smooth Muscle

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Su1539 Mechanisms of PTHrP-induced Suppression of Gastric Smooth Muscle Contractility in the Guinea Pig Stomach

Gastroenterology ◽

10.1016/s0016-5085(16)31792-9 ◽

2016 ◽

Vol 150 (4) ◽

pp. S521

Author(s):

Hideomi Ohguchi ◽

Hikaru Hashitani ◽

Kenro Imaeda ◽

Mayo Hachiya ◽

Eiji Kubota ◽

...

Keyword(s):

Smooth Muscle ◽

Guinea Pig ◽

Muscle Contractility ◽

Smooth Muscle Contractility ◽

Gastric Smooth Muscle ◽

Guinea Pig Stomach

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

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.1982.242.4.g400 ◽

1982 ◽

Vol 242 (4) ◽

pp. G400-G407 ◽

Cited By ~ 8

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.

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