Hyperlipidemia impairs uterine β-adrenergic signaling by reducing cAMP in late pregnant rats

The aim of the present study was to reveal the effect of hyperlipidemia on β2- and β3-adrenergic signaling in late pregnant rat uterus. Hyperlipidemia was induced in female Wistar rats by feeding a high-fat high-cholesterol diet for 8 weeks before and after mating upto the 21st day of gestation. The effect of hyperlipidemia on β-adrenergic signaling was studied with the help of tension experiments, real-time PCR and cAMP ELISA in 21-day pregnant rat uterus. In tension experiments, hyperlipidemia neither altered the spontaneous contractility nor the oxytocin-induced contractions. However, it decreased the −logEC50 values of β2-adrenoceptor agonist, salbutamol and β3-adrenoceptor agonist, BRL37344. It also decreased the efficacy of adenylyl cyclase activator, forskolin. Further, there was a significant decrease in salbutamol and BRL37344-stimulated cAMP content in uterine tissues. However, there was no alteration in mRNA expressions of β2-adrenoceptor (Adrb2), β3-adrenoceptor (Adrb3) and Gs protein (Gnas) though there was a significant increase in the mRNA expression of Gi protein (Gnai). In conclusion, reduced cAMP content after beta-adrenergic receptor stimulation, which correlates with an increase in Gnai mRNA, may explain the mechanism of the impairment of uterine β-adrenergic signaling in hyperlipidemic pregnant rats. The clinical implication of the present study may relate to reduced myometrial relaxant response to β-adrenergic agonists in high fat-induced uterine dysfunction.

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Potent inhibition of spontaneous rhythmic contraction by a novel β2-adrenoceptor agonist, HSR-81, in pregnant rat uterus.

The Japanese Journal of Pharmacology ◽

10.1016/s0021-5198(19)50480-2 ◽

1994 ◽

Vol 64 ◽

pp. 212

Author(s):

Tetsuo Ohashi ◽

Shigeki Hashimoto ◽

Kouji Morikawa ◽

Hideo Kato ◽

Yasuo Ito ◽

...

Keyword(s):

Rhythmic Contraction ◽

Rat Uterus ◽

Pregnant Rat ◽

Adrenoceptor Agonist ◽

Potent Inhibition

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Immunohistochemical Localization of Cyclooxygenase-2 in Pregnant Rat Uterus by Sp-6 Acupuncture

The American Journal of Chinese Medicine ◽

10.1142/s0192415x0300117x ◽

2003 ◽

Vol 31 (03) ◽

pp. 481-488 ◽

Cited By ~ 8

Author(s):

Jeong-Sang Kim ◽

Chang Su Na ◽

Woo Jun Hwang ◽

Byung Chul Lee ◽

Ki Hyoung Shin ◽

...

Keyword(s):

Acupuncture Treatment ◽

Immunohistochemical Localization ◽

Cyclooxygenase 2 ◽

Uterine Contractility ◽

Rat Uterus ◽

Pregnant Rats ◽

Pregnant Rat ◽

Complementary Method ◽

Key Factor ◽

Cox 2

As pregnancy advances, prostaglandins (PG) increase in the uterus, leading to elevated uterine contractility. Therefore, regulating the concentration of PG in the uterus can be a key factor for controlling the duration of labor. Since the synthesis of PGs in the uterus is catalyzed by cyclooxygenase-2 (COX-2), devising a tool to regulate the expression of COX-2 could provide a method for treating complicated labor. In this study, Sp-6 acupuncture treatment was evaluated for its potential in controlling uterine motility. Immunohistochemical methods showed the COX-2 enzyme was primarily found in the endometrium and myometrium of rat uterus. COX-2 expression in these two locations were intensified by pregnancy, but reduced by acupuncture at the Sp-6 acupoint. Uterine motility monitored during Sp-6 acupuncture was reduced by 28.15% (p < 0.05) and 19.88% (p < 0.05) in pregnant rats and non-pregnant rats, respectively. The significant reduction of uterine motility in pregnant rat suggests a role for Sp-6 acupuncture in regulating the expression of COX-2 during pregnancy. These results suggest that Sp-6 acupuncture could be used as a complementary method for controlling labor in human pregnancy.

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Potent inhibition of spontaneous rhythmic contraction by a novel β2-adrenoceptor agonist, HSR-81, in pregnant rat uterus

European Journal of Pharmacology ◽

10.1016/0014-2999(96)00277-4 ◽

1996 ◽

Vol 307 (3) ◽

pp. 315-322 ◽

Cited By ~ 7

Author(s):

Tetsuo Ohashi ◽

Shigeki Hashimoto ◽

Kouji Morikawa ◽

Hideo Kato ◽

Yasuo Ito ◽

...

Keyword(s):

Rhythmic Contraction ◽

Rat Uterus ◽

Pregnant Rat ◽

Adrenoceptor Agonist ◽

Potent Inhibition

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PEPTIDOGLYCAN OF STAPHYLOCOCCUS AUREUS ALTERS THE MYOMETRIAL CONTRACTILITY OF NON-PREGNANT RATS TROUGH INCREASING INTRACELLULAR CALCIUM LEVELS

Fiziolohichnyĭ zhurnal ◽

10.15407/fz66.06.056 ◽

2020 ◽

Vol 66 (6) ◽

pp. 56-65

Author(s):

L.S. Nasibian ◽

◽

H.V. Sotkis ◽

O.M. Tzugorko ◽

I.B. Philippov ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Calcium Ions ◽

Rat Uterus ◽

Pregnant Rats ◽

Pregnant Rat ◽

Relaxation Phase ◽

Intracellular Content ◽

Long Time ◽

Myometrial Contractility ◽

Spontaneous Contractions

The work is devoted to the study of the effect of Staphylococcus aureus peptidoglycan on the main parameters of myometrial contractions and the mechanism of this influence. The research was carried out by tensometry and calcimetry methods. The results of the experiments demonstrated that peptidoglycan modulates all the main parameters of contractions of the non-pregnant rat uterus, including increasing their amplitude and duration by 10 and 30%, respectively, mainly by prolonging the relaxation phase (56.7 ± 1.6%): myometrial band relative to quickly shrunk and relaxed for a long time. Application of peptidoglycan on freshly isolated uterine myocytes for 5 min led to a periodic increase in their intracellular content of calcium ions. Peptidoglycan enhanced myometrial contractions caused by hyperpotassium solution at a concentration of 60 mmol. Administration of 1 μmol of nifedipine, a blocker of potential-directed L-type calcium channels, suppressed spontaneous contractions enhanced by peptidoglycan. These changes in myometrium contractility of on the background of peptidoglycan action occur not only due to increased transmembrane calcium intake, but also its mobilization from the sarcoplasmic reticulum.

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Prolonged stretching in the late-late pregnant rat uterus inhibits contractions through potassium channel TREK-1

10.21203/rs.3.rs-30853/v1 ◽

2020 ◽

Author(s):

Zongzhi Yin ◽

Yun Li ◽

Dan Li ◽

Jingjing Su ◽

Bing Shen ◽

...

Keyword(s):

Arachidonic Acid ◽

Potassium Channel ◽

Isometric Contraction ◽

Late Pregnancy ◽

Rat Uterus ◽

Pregnant Rats ◽

Pregnant Rat ◽

Pregnant Uterus ◽

Myometrial Contractility

Abstract Background Prolonged stretching can inhibit myometrial contractions in the nonpregnant and the mid- and late-term pregnant uteri of rats and humans through potassium channel TREK-1. What happens in the pregnant uterus close to parturition remains unknown. Methods Uterine tissues from late-late pregnant rats (day 20–21 of pregnancy) were isolated, and myometrial strips were prepared for isometric contraction measurements. We compared the oxytocin-induced contractions of myometrial strips treated with different stretch times and doses. Then, we used the potassium channel TREK-1 inhibitor L-methionine and TREK-1 agonist arachidonic acid to determine whether the changes caused by prolonged stretching involved changes in TREK-1 activity. Results Prolonged stretching caused relaxation of the myometrial strips that were close to parturition. Additionally, TREK-1 inhibition partly reversed the myometrial relaxation caused by prolonged stretching of the late-late pregnant rat uterus, while TREK-1 activation resulted in a dramatic myometrial contraction change. Conclusions Prolonged stretching can inhibit myometrial contractility and induce myometrial relaxation in late-late pregnancy. This contractile inhibition is partly due to functional upregulation of potassium channel TREK-1.

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PROGESTERONE IN THE UTERUS

Acta Endocrinologica ◽

10.1530/acta.0.0770160 ◽

1974 ◽

Vol 77 (1) ◽

pp. 160-170 ◽

Cited By ~ 4

Author(s):

D. Egert ◽

H. Maass

Keyword(s):

Extracellular Fluid ◽

Uterine Tissue ◽

Rat Uterus ◽

Pregnant Rats ◽

Pregnant Rat

ABSTRACT Radio-metabolites of progesterone and progesterone itself were found in the uteri of intact pregnant rats 20 min after injection of [1,2-3H]progesterone. However, after evisceration and removal of the foeto-placental unit, and following injection of the labelled steroid, the progesterone content in the extract from the pregnant rat uterus markedly increased while the metabolite levels correspondingly decreased. An analogous change was observed in the plasma. Thus it appears probable that progesterone is not metabolized in the uterus of pregnant rats, and that metabolites found in this tissue originate predominantly in the foetoplacental system and appear in the plasma and extracellular fluid present in the uterine tissue.

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