Modulation of Iris Sphincter and Ciliary Muscles by Urocortin 2

Urocortin 2 (UCN2) is a peptide related to corticotropin-releasing factor, capable of activating CRF-R2. Among its multisystemic effects, it has actions in all 3 muscle subtypes. This study’s aim was to determine its potential role in two of the intrinsic eye muscle kinetics. Strips of iris sphincter (rabbit) and ciliary (bovine) muscles were dissected and mounted in isometric force-transducer systems filled with aerated-solutions. Contraction was elicited using carbachol (10-6 M for iris sphincter, 10-5 M for ciliary muscle), prior adding to all testing substances. UCN2 induced relaxation in iris sphincter muscle, being the effect maximal at 10-7 M concentrations (-12.2 % variation vs. control). This effect was abolished with incubation of indomethacin, antisauvagine-30, chelerytrine and SQ22536, but preserved with L-nitro-L-arginine. In carbachol pre-stimulated ciliary muscle, UCN2 (10-5 M) enhanced contraction (maximal effect of 18.2 % increase vs. control). UCN2 is a new modulator of iris sphincter relaxation, dependent of CRF-R2 activation, synthesis of prostaglandins (COX pathway) and both adenylate cyclase and PKC signaling pathways, but independent of nitric oxide production. Regarding ciliary muscle, UCN2 enhances carbachol-induced contraction, in higher doses.

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Faculty Opinions recommendation of Social stress-induced bladder dysfunction: potential role of corticotropin-releasing factor.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1157544.617744 ◽

2009 ◽

Author(s):

Rodolfo Testa

Keyword(s):

Social Stress ◽

Potential Role ◽

Bladder Dysfunction ◽

Corticotropin Releasing Factor

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Faculty Opinions recommendation of Social stress-induced bladder dysfunction: potential role of corticotropin-releasing factor.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1157544.617728 ◽

2009 ◽

Author(s):

Peggy Mason

Keyword(s):

Social Stress ◽

Potential Role ◽

Bladder Dysfunction ◽

Corticotropin Releasing Factor

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Effect of Prostaglandins on Cultured Porcine Iris Sphincter Muscle Cells

Journal of Ocular Pharmacology and Therapeutics ◽

10.1089/jop.1996.12.343 ◽

1996 ◽

Vol 12 (3) ◽

pp. 343-351 ◽

Cited By ~ 2

Author(s):

NAOYA FUJIMOTO ◽

HITOSHI SHICHI

Keyword(s):

Muscle Cells ◽

Sphincter Muscle ◽

Iris Sphincter

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Synergistic Signaling by Light and Acetylcholine in Mouse Iris Sphincter Muscle

Current Biology ◽

10.1016/j.cub.2017.05.022 ◽

2017 ◽

Vol 27 (12) ◽

pp. 1791-1800.e5 ◽

Cited By ~ 10

Author(s):

Qian Wang ◽

Wendy Wing Sze Yue ◽

Zheng Jiang ◽

Tian Xue ◽

Shin H. Kang ◽

...

Keyword(s):

Sphincter Muscle ◽

Iris Sphincter

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Levels of IMeurokinin A, Neurokinin B and Substance P in Rabbit Iris Sphincter Muscle

The Japanese Journal of Pharmacology ◽

10.1254/jjp.42.590 ◽

1986 ◽

Vol 42 (4) ◽

pp. 590-593 ◽

Cited By ~ 18

Author(s):

Takashi TANIGUCHI ◽

Motohatsu FUJIWARA ◽

Yoshinori MASUO ◽

Ichiro KANAZAWA

Keyword(s):

Substance P ◽

Sphincter Muscle ◽

Neurokinin B ◽

Rabbit Iris Sphincter Muscle ◽

Rabbit Iris Sphincter ◽

Rabbit Iris ◽

Iris Sphincter

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Neonatal Rat Hearts Cannot Be Protected by Ischemic Postconditioning

Physiological Research ◽

10.33549/physiolres.932981 ◽

2015 ◽

pp. 789-794 ◽

Cited By ~ 1

Author(s):

J. DOUL ◽

Z. CHARVÁTOVÁ ◽

I. OŠŤÁDALOVÁ ◽

M. KOHUTIAR ◽

H. MAXOVÁ ◽

...

Keyword(s):

Isometric Force ◽

Ischemia Reperfusion ◽

Force Transducer ◽

Global Ischemia ◽

Ischemic Postconditioning ◽

Neonatal Rat ◽

Postnatal Life ◽

Protective Effects ◽

Rat Hearts ◽

Ldh Release

Although there are abundant data on ischemic postconditioning (IPoC) in the adult myocardium, this phenomenon has not yet been investigated in neonatal hearts. To examine possible protective effects of IPoC, rat hearts isolated on days 1, 4, 7 and 10 of postnatal life were perfused according to Langendorff. Developed force (DF) of contraction was measured by an isometric force transducer. Hearts were exposed to 40 or 60 min of global ischemia followed by reperfusion up to the maximum recovery of DF. IPoC was induced by three cycles of 10, 30 or 60 s periods of global ischemia/reperfusion. To further determine the extent of ischemic injury, lactate dehydrogenase (LDH) release was measured in the coronary effluent. Tolerance to ischemia did not change from day 1 to day 4 but decreased to days 7 and 10. None of the postconditioning protocols tested led to significant protection on the day 10. Prolonging the period of sustained ischemia to 60 min on day 10 did not lead to better protection. The 3x30 s protocol was then evaluated on days 1, 4 and 7 without any significant effects. There were no significant differences in LDH release between postconditioned and control groups. It can be concluded that neonatal hearts cannot be protected by ischemic postconditioning during first 10 days of postnatal life.

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Sevoflurane Inhibits Guanosine 5′-[γ-thio]triphosphate–stimulated, Rho/Rho-kinase–mediated Contraction of Isolated Rat Aortic Smooth Muscle

Anesthesiology ◽

10.1097/00000542-200309000-00020 ◽

2003 ◽

Vol 99 (3) ◽

pp. 646-651 ◽

Cited By ~ 13

Author(s):

Jingui Yu ◽

Koji Ogawa ◽

Yasuyuki Tokinaga ◽

Yoshio Hatano

Keyword(s):

Smooth Muscle ◽

Kinase Inhibitor ◽

Isometric Force ◽

Rho Kinase ◽

Force Transducer ◽

Dependent Manner ◽

Concentration Dependent Manner ◽

Aortic Smooth Muscle ◽

Gamma S ◽

Kinase Pathway

Background The Rho/Rho-kinase signaling pathway plays an important role in mediating Ca2+ sensitization of vascular smooth muscle. The effect of anesthetics on Rho/Rho-kinase-mediated vasoconstriction has not been determined to date. This study is designed to examine the possible inhibitory effects of sevoflurane on the Rho/Rho-kinase pathway by measuring guanosine 5'-[gamma-thio]triphosphate (GTP gamma S)-stimulated contraction and translocation of RhoA (one of the three Rho subtypes) and Rock-2 (one of the two Rho-kinase subtypes) from the cytosol to the membrane in rat aortic smooth muscle. Methods GTP gamma S-induced contraction of rat aortic endothelium-denuded rings was measured using an isometric force transducer, and GTP gamma S-stimulated membrane translocation of RhoA and Rock-2 in smooth muscle cells was detected with Western blotting in the presence and absence of sevoflurane. Results GTP gamma S (10(-4) m) induced a sustained contraction, which was significantly inhibited by the Rho-kinase inhibitor, Y27632 (3 x 10(-6) m). Before treatment with GTP gamma S, RhoA and Rock-2 were detected primarily in the cytosolic fraction. GTP gamma S (10(-4) m) stimulated the translocation of RhoA and Rock-2 from the cytosol to the membrane, which was sustained for more than 60 min. Sevoflurane (1.7, 3.4, and 5.1%) concentration dependently inhibited the GTP gamma S-induced constriction of rat aortic smooth muscle with a reduction of constriction of 52-75% (P < 0.01, n = 8), and attenuated the translocation of RhoA and Rock-2 by 31-66% and 34-78%, respectively (P < 0.05-0.01, respectively; n = 4). Conclusion The current findings show that sevoflurane depresses the GTP gamma S-stimulated contraction and translocation of both Rho and Rho-kinase from the cytosol in a concentration-dependent manner, indicating that sevoflurane is able to inhibit vasoconstriction mediated by the Rho/Rho-kinase pathway in rat aortic smooth muscle.

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Determination of impact of Azadirachta indica L. leaves on adults and eggs of Callosobruchus maculatus Fabricius, the largest predator of stored cowpea (Vigna unguiculata Walp) by an applicable method by farmers

South Asian Journal of Experimental Biology ◽

10.38150/sajeb.4(5).p215-221 ◽

2015 ◽

Vol 4 (5) ◽

pp. 215-221

Author(s):

Ablaye Faye ◽

Malick Sarr ◽

Abdoulaye Samb ◽

Cheikh Thiaw ◽

Keyword(s):

Mortality Rate ◽

Callosobruchus Maculatus ◽

Maximum Effect ◽

Maximal Effect ◽

Cowpea Weevil ◽

Lethal Effects ◽

Neem Leaves ◽

Leaf Powder ◽

Higher Doses

The effect of neem leaves has been tested in the laboratory on eggs and adults of cowpea weevil (C. maculatus). Different formulations of this plant were applied to these forms of C. maculatus Fab. Grinding fresh contact sheets induced significant lethal effects from 96.12% to 100% on eggs; whereas 100% of mortality was recorded at the end of eight days of applica-tion to three adults with higher doses. Fumigation on turn proved less effec-tive than contact on eggs. It induced a maximal effect of 95.73% mortality with the larger dose (D4: 0.02912g/cm3). On adults, we recorded highest mortality (100%) from the 7th day of the show with the highest dose. The aqueous extract of neem leaf powder was less effective than all other formu-lations on the eggs as well as adults of this insect; with a higher mortality rate (74.99%) observed on the eggs with the application of the concentration C2. On adults we recorded a maximum effect (100% mortality) from the 13th day of the application with the highest concentration (C1). These mortalities would be related to the support of several active molecules contained in neem as established in literature.

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