Gap Junctions are Found between Iris Sphincter Smooth Muscle Cells but not in the Ciliary Muscle of Human and Monkey Eyes

1996 ◽  
Vol 63 (2) ◽  
pp. 187-192 ◽  
Author(s):  
UNDINE SAMUEL ◽  
ELKE LÜTJEN-DRECOLL ◽  
ERNST R. TAMM
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Gap Junctions ◽  
Muscle Cells ◽  
Ciliary Muscle ◽  
Iris Sphincter

scholarly journals Involvement of gap junctions between smooth muscle cells in sustained hypoxic pulmonary vasoconstriction development: a potential role for 15-HETE and 20-HETE

2016 ◽  
Vol 310 (8) ◽  
pp. L772-L783 ◽  
Author(s):  
Igor V. Kizub ◽  
Anand Lakhkar ◽  
Vidhi Dhagia ◽  
Sachindra R. Joshi ◽  
Houli Jiang ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Gap Junctions ◽  
Force Measurement ◽  
Isometric Force ◽  
Hypoxic Pulmonary Vasoconstriction ◽  
Muscle Cells ◽  
Cytochrome P450 Monooxygenases ◽  
Prostaglandin E ◽  
Pulmonary Vasoconstriction

In response to hypoxia, the pulmonary artery normally constricts to maintain optimal ventilation-perfusion matching in the lung, but chronic hypoxia leads to the development of pulmonary hypertension. The mechanisms of sustained hypoxic pulmonary vasoconstriction (HPV) remain unclear. The aim of this study was to determine the role of gap junctions (GJs) between smooth muscle cells (SMCs) in the sustained HPV development and involvement of arachidonic acid (AA) metabolites in GJ-mediated signaling. Vascular tone was measured in bovine intrapulmonary arteries (BIPAs) using isometric force measurement technique. Expression of contractile proteins was determined by Western blot. AA metabolites in the bath fluid were analyzed by mass spectrometry. Prolonged hypoxia elicited endothelium-independent sustained HPV in BIPAs. Inhibition of GJs by 18β-glycyrrhetinic acid (18β-GA) and heptanol, nonspecific blockers, and Gap-27, a specific blocker, decreased HPV in deendothelized BIPAs. The sustained HPV was not dependent on Ca2+entry but decreased by removal of Ca2+and by Rho-kinase inhibition with Y-27632. Furthermore, inhibition of GJs decreased smooth muscle myosin heavy chain (SM-MHC) expression and myosin light chain phosphorylation in BIPAs. Interestingly, inhibition of 15- and 20-hydroxyeicosatetraenoic acid (HETE) synthesis decreased HPV in deendothelized BIPAs. 15-HETE- and 20-HETE-stimulated constriction of BIPAs was inhibited by 18β-GA and Gap-27. Application of 15-HETE and 20-HETE to BIPAs increased SM-MHC expression, which was also suppressed by 18β-GA and by inhibitors of lipoxygenase and cytochrome P450 monooxygenases. More interestingly, 15,20-dihydroxyeicosatetraenoic acid and 20-OH-prostaglandin E2, novel derivatives of 20-HETE, were detected in tissue bath fluid and synthesis of these derivatives was almost completely abolished by 18β-GA. Taken together, our novel findings show that GJs between SMCs are involved in the sustained HPV in BIPAs, and 15-HETE and 20-HETE, through GJs, appear to mediate SM-MHC expression and contribute to the sustained HPV development.

Immortalization of cat iris sphincter smooth muscle cells by SV40 virus: Growth, morphological, biochemical and pharmacological characteristics

1995 ◽  
Vol 61 (5) ◽  
pp. 535-545 ◽  
Author(s):  
Anette Ocklind ◽  
Sardar Y.K. Yousufzai ◽  
Sikha Ghosh ◽  
Miguel Coca-Prados ◽  
Johan St Jernschantz ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Muscle Cells ◽  
Virus Growth ◽  
Sv40 Virus ◽  
Iris Sphincter

Effects of the gap junction blocker glycyrrhetinic acid on gastrointestinal smooth muscle cells

2005 ◽  
Vol 288 (4) ◽  
pp. G832-G841 ◽  
Author(s):  
Yukari Takeda ◽  
Sean M. Ward ◽  
Kenton M. Sanders ◽  
Sang Don Koh
Keyword(s):  
Smooth Muscle ◽  
Patch Clamp ◽  
Smooth Muscle Cells ◽  
Gap Junctions ◽  
Lucifer Yellow ◽  
Muscle Cells ◽  
Glycyrrhetinic Acid ◽  
Delayed Rectifier ◽  
Dependent Manner ◽  
Patch Clamp Technique

In the tunica muscularis of the gastrointestinal (GI) tract, gap junctions form low-resistance pathways between pacemaker cells known as interstitial cells of Cajal (ICCs) and between ICC and smooth muscle cells. Coupling via these junctions facilitates electrical slow-wave propagation and responses of smooth muscle to enteric motor nerves. Glycyrrhetinic acid (GA) has been shown to uncouple gap junctions, but previous studies have shown apparent nonspecific effects of GA in a variety of tissues. We tested the effects of GA using isometric force measurements, intracellular microelectrode recordings, the patch-clamp technique, and the spread of Lucifer yellow within cultured ICC networks. In murine small intestinal muscles, β-GA (10 μM) decreased phasic contractions and depolarized resting membrane potential. Preincubation of GA inhibited the spread of Lucifer yellow, increased input resistance, and decreased cell capacitance in ICC networks, suggesting that GA uncoupled ICCs. In patch-clamp experiments of isolated jejunal myocytes, GA significantly decreased L-type Ca2+ current in a dose-dependent manner without affecting the voltage dependence of this current. The IC50 for Ca2+ currents was 1.9 μM, which is lower than the concentrations used to block gap junctions. GA also significantly increased large-conductance Ca2+-activated K+ currents but decreased net delayed rectifier K+ currents, including 4-aminopyridine and tetraethylammonium-resistant currents. In conclusion, the reduction of phasic contractile activity of GI muscles by GA is likely a consequence of its inhibitory effects on gap junctions and voltage-dependent Ca2+ currents. Membrane depolarization may be a consequence of uncoupling effects of GA on gap junctions between ICCs and smooth muscles and inhibition of K+ conductances in smooth muscle cells.

Gap Junctions Formed of Connexin43 Are Found Between Smooth Muscle Cells of Human Corpus Cavernosum

1993 ◽  
Vol 149 (6) ◽  
pp. 1568-1575 ◽  
Author(s):  
A.C. Campos De Carvalho ◽  
C. Roy ◽  
A.P. Moreno ◽  
A. Melman ◽  
E.L. Hertzberg ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Gap Junctions ◽  
Corpus Cavernosum ◽  
Muscle Cells

Gap junctions and direct intercellular communication between rat uterine smooth muscle cells

1985 ◽  
Vol 249 (1) ◽  
pp. C20-C31 ◽  
Author(s):  
W. C. Cole ◽  
R. E. Garfield ◽  
J. S. Kirkaldy
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Gap Junctions ◽  
Intercellular Communication ◽  
Contractile Activity ◽  
Muscle Cells ◽  
Uterine Wall ◽  
Longitudinal Distribution ◽  
Uterine Smooth Muscle ◽  
Apparent Diffusion

We have tested the hypothesis that an increase in direct intercellular communication accompanies the development of gap junctions (GJs) between rat uterine smooth muscle cells at parturition. Intercellular communication in these tissues was studied by exposing one portion of small strips of myometrium to 2-[3H]deoxy-D-glucose (2-DG) and determining the longitudinal distribution of tracer after a 5-h period of diffusion. The distribution of 2-DG was greater in parturient compared with ante- and postpartum tissues. Similarly, the apparent diffusion coefficient of 2-DG was almost 10-fold greater in delivering tissues (1.86 X 10(-6) cm2/s) than before (0.199 X 10(-6) cm2/s) or after (0.296 X 10(-6) cm2/s) parturition. Control experiments indicated that the redistribution of 2-DG was dependent on the presence of GJs and was the result of intracellular and direct cell-to-cell diffusion. The appearance of GJs is the myometrium at term facilitates direct intercellular communication between uterine smooth muscle cells during labor. This improved communication may be responsible for synchronizing and coordinating electrical, metabolic, and contractile activity in the uterine wall and, hence, the effective expulsion of fetuses.

Changes of gap junctions in myometrium of guinea pig at parturition and abortion

1982 ◽  
Vol 60 (3) ◽  
pp. 335-341 ◽  
Author(s):  
R. E. Garfield ◽  
E. E. Daniel ◽  
M. Dukes ◽  
J. D. Fitzgerald
Keyword(s):  
Smooth Muscle ◽  
Guinea Pig ◽  
Smooth Muscle Cells ◽  
Gap Junctions ◽  
Gap Junction ◽  
Electron Micrographs ◽  
Guinea Pigs ◽  
Muscle Cells ◽  
Similar Increase ◽  
Junction Area

Myometrial tissues from guinea pigs were quantitatively examined for gap junctions in electron micrographs. Small numbers of gap junctions were present between smooth muscle cells in myometria of pregnant guinea pigs at days 50 and 65 of gestation. The junctions increased in number and size at parturition on day 69 and decreased again to control levels 24 h after parturition. A similar increase in junctions occurred when abortion was induced by 16,16-dimethylprostaglandin E2 (PGE2) on day 65. There were no consistent or significant differences in numbers of gap junctions from myometrium taken over sites of placental attachment and from other sites. These results together with previous studies suggest that an increase in myometrial gap junction area is associated with and may be essential for parturition in guinea pigs, but the control of their development may differ from that in other mammals.

Sign in / Sign up

Export Citation Format

Share Document