Effects of colchicine on gap junction formation during retinal neurogenesis

1981 ◽  
Vol 163 (3) ◽  
pp. 321-330 ◽  
Author(s):  
Karl Meller
2004 ◽  
Vol 86 (2) ◽  
pp. 781-796 ◽  
Author(s):  
Derek L. Beahm ◽  
James E. Hall

1986 ◽  
Vol 250 (3) ◽  
pp. C495-C505 ◽  
Author(s):  
R. Agrawal ◽  
E. E. Daniel

This study examined whether the synthesis of the metabolites of arachidonic acid (AA) was involved in gap junction formation by 4-aminopyridine (4-AP) treatment in vitro in canine trachealis. Studies were made of the effects on gap junction formation of putative inhibitors of the cyclooxygenase and of both this and the lipoxygenase pathway of AA metabolism and the direct effects of prostaglandins (PG) E2 and I2. The number of gap junctions of similar size was increased after brief exposure to 4-AP. After indomethacin (IDM), 4-AP treatment decreased the number of gap junctions but did not affect their size. Pretreatment with 5,8,11,14-eicosatetraynoic acid or nordihydroguiaretic acid, putative inhibitors of cyclooxygenase and lipoxygenase enzymes, inhibited both the 4-AP-induced increase and decrease in the number of gap junctions. FPL 55712, a putative antagonist of leukotriene C4, did not alter either the number or the size of gap junctions when added alone or in combination with IDM. AA alone increased the number of gap junctions, but after IDM, AA decreased the number of gap junctions compared with the controls. Incubation of trachealis strips in vitro for 30 min with PGE2 increased the number of gap junctions by about threefold along with an increase in the size of the gap junctions. Similar incubation with PGI2, however, increased the number of gap junctions by approximately 60% without any change in the size. In the course of some control experiments, an interaction between carbachol and alcohol was observed such that alcohol caused an IDM-sensitive relaxation of carbachol-induced contractions, which was not observed when serotonin was the contractile agent. These results strongly suggest that PGE2 and PGI2 increase the formation of gap junctions in canine trachealis and that these prostanoids are released by 4-AP treatment. Leukotrienes may also be inhibitory in the formation of gap junctions, but FPL 55712 did not affect either the increase or the decrease in gap junctions after 4-AP.


1989 ◽  
Vol 15 (6) ◽  
pp. 895-908 ◽  
Author(s):  
Ronald E. Gordon ◽  
Richard F. Heller ◽  
J. Robert Del Valle ◽  
Rachael F. Heller

2020 ◽  
Vol 55 (5) ◽  
pp. 574-587.e3
Author(s):  
Lingfeng Meng ◽  
Dong Yan

1991 ◽  
Vol 69 (9) ◽  
pp. 1262-1267 ◽  
Author(s):  
W. Y. Chan ◽  
Irene Berezin ◽  
E. E. Daniel ◽  
K. C. Russell ◽  
Victor J. Hruby

Normal term labor is associated with a surge in myometrial oxytocin receptor formation and gap junction development. We have previously shown that inhibition of prostaglandin synthesis by naproxen sodium, 2.0 mg/day, suppressed oxytocin receptor formation but not gap junction formation and prolonged gestation. In this study, we investigated the effects of a specific oxytocin antagonist on oxytocin receptor formation, gap junction formation, and labor in the rat. [Pen1Phe(Me)2,Thr4,Orn8]oxytocin, a specific oxytocin antagonist, was infused subcutaneously during the last 3 days of pregnancy at 300 μg/day. Measurements of myometrial oxytocin receptor concentrations and gap junction formation on days 21 and 22 and days 22–23 (in labor) pregnant uteri showed no significant differences in the Bmax and Kd values between the control and the treated group. Gestation period was not prolonged by the oxytocin antagonist. However, in a separate group of day 23 pregnant rats, the uterine contractile response to 60 mU of oxytocin i.v. was found completely blocked by 10 μg of the oxytocin antagonist. These findings suggest that although functional oxytocin receptors did not appear to be essential for the initiation of labor, oxytocin antagonists may still be effective in the prevention of premature contractions. We also examined the effects of a higher dose of naproxen sodium, 5.0 mg/day, on gap junction formation. At this dose, naproxen sodium suppressed both oxytocin receptor and gap junction formation, prolonged gestation, and delayed parturition by 24 h or longer. Prostaglandin appears to be an important regulator or mediator of oxytocin receptor and gap junction formation and plays a critical role in the initiation of labor.Key words: oxytocin, prostaglandin, oxytocin receptor, gap junction, labor.


2012 ◽  
Vol 75 (12) ◽  
pp. 1632-1638 ◽  
Author(s):  
Eisuke Sakuma ◽  
Ikuo Wada ◽  
Takanobu Otsuka ◽  
Kenjiro Wakabayashi ◽  
Kinya Ito ◽  
...  

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