PubMed Health⌕ Search

Biomedical subjects

S Acritopoulou-Fourcroy

Publications and source records attributed to S Acritopoulou-Fourcroy.

6 recordsLinked to original sources
PubMed1988

Involvement of alpha-adrenoceptors in myometrial responses in the pro-oestral rat.

1. Myometrial responses to different agents acting on adrenoceptors were examined in vivo in the pro-oestrous rat. Changes in spontaneous uterine mechanical activity were recorded isometrically and evaluated in terms of amplitude and duration of uterine contractions. 2. Phenylephrine (10 micrograms kg-1) markedly increased the amplitude and duration of contractions and 40 micrograms kg-1 gave rise to tetanic contractions. 3. Administration of either nicergoline (400 micrograms kg-1) or phentolamine (1000 micrograms kg-1) to phenylephrine-primed rat uterus reduced the strength of contractions and phentolamine abolished the phenylephrine-induced uterine contracture. 4. Following blockade of alpha 2-adrenoceptors by yohimbine (1000 micrograms kg-1) and beta-adrenoceptors by propranolol (2400 micrograms kg-1), a single injection of phenylephrine (100 micrograms kg-1) increased the amplitude of uterine contractions by 30%. 5. Noradrenaline reduced the amplitude of contractions and caused elevation of the baseline level. The response of myometrium to the combination of both propranolol and noradrenaline was the establishment of uterine contracture with subsequent increase of the duration of contractions. 6. These results clearly demonstrate the involvement of alpha-adrenoceptors in the myometrial activity of the rat in vivo during pro-oestrus.

Animals↗
PubMed1988

Increase of uterine motility and simultaneous decrease of progesterone concentrations in the rat after bilateral ovariectomy at mid-pregnancy.

Comparison of uterine activities recorded during the control period to those obtained during the two recording periods after ovariectomy (0-30 min and 30-60 min) showed an increase of the amplitude of uterine contractions (P less than 0.005) and a decrease of the interval between two successive uterine contractions (P less than 0.005) and the delay of electrical activities (P less than 0.005). Progesterone treatment (50 mg/kg i.m.) of ovariectomized rats prevented the abrupt fall in plasma progesterone concentrations, measured by RIA, which in turn inhibited the increase of uterine mechanical and electrical activities. A close relation between the increase of myometrial activity and the decrease of progesterone concentrations after ovariectomy is suggested. The activation of the myometrium would be principally induced by the fall of progesterone or by the variation of the oestrogen/progesterone ratio; these changes in sexual steroid hormones would augment the uterine sensitivity to physiological stimuli or modify the activity of other factors involved in the regulation of the myometrium.

Animals↗
PubMed1988

Variation of myometrial activities and steroid sexual hormones following bilateral ovariectomy in the rat at midpregnancy.

The effects of bilateral ovariectomy on uterine motility and levels of progesterone, oestradiol, cAMP, adrenaline and PGF2 alpha were studied in the rat at midpregnancy. Animals were randomly divided into two groups, at least 15 rats in each, sham-operated serving as controls and ovariectomized. The spontaneous uterine mechanical activity of Wistar rats was recorded isometrically and the electrical activities were recorded simultaneously by two bipolar electrodes. Within 30 minutes of ovariectomy a significant increase of the amplitude of uterine contractions was observed and the simultaneity of electrical activity was significantly improved; these effects became more pronounced at 1h post-ovariectomy (p less than 0.005). Plasma progesterone levels decreased by 20% (p less than 0.01) at 30 min and by 50% (p less than 0.001) 1h after ovariectomy, whereas oestrogen levels remained unchanged. Levels of adrenaline, cAMP and PGF2 alpha in the uterine tissue 1h following ovariectomy were affected as follows: adrenaline (p less than 0.05) and cAMP (p less than 0.001) were reduced and PGF2 alpha augmented (p less than 0.05). It appears that variation of the ratio oestrogens/progesterone induces precociously the activation of uterine mobility and exerts an effect on some factors involved in the regulation of the rat myometrium at midpregnancy.

Animals↗
PubMed1984

Myometrial responses in situ to nicergoline, acebutolol, phentolamine and noradrenaline of the rat in proestrus.

The effects of two adrenoceptor antagonists, nicergoline (alpha 1) and acebutolol (beta 1), on the contraction of myometrium in the proestrous rat were compared to those of noradrenaline and phentolamine. The spontaneous myometrial contractions of Wistar rats on the day of proestrus were recorded isometrically and the data were analysed using Wilcoxon non-parametric statistics. All drugs were administered i.v. and the doses are expressed as microgram/kg body weight. Noradrenaline (1200 micrograms/kg per h) induced a 32.5% reduction (P less than 0.001) of the uterine contraction amplitude. Nicergoline did not alter uterine motility significantly when administered alone at doses ranging from 400 to 1600 micrograms/kg. However, successive injections of nicergoline in the same range given during noradrenaline infusion at 600 micrograms/kg per h potentiated the relaxing action of the latter (38%, P less than 0.01). Phentolamine (120 micrograms/kg) reduced myometrial activity by 25% (P less than 0.05). This inhibitory response rose to 65% (P less than 0.001) when the dose of phentolamine was increased to 960 micrograms/kg. When a single injection of nicergoline (400 micrograms/kg) was followed by the administration of increasing doses of acebutolol (120, 1200, 2400 micrograms/kg) the slight inhibitory effect on uterine motility observed after administration of each of the two agents separately became more pronounced (P less than 0.05). It appears from these results that combining noradrenaline with nicergoline and nicergoline with acebutolol leads to potentiation of their relaxing effects. Furthermore the results confirm that nicergoline is a partial alpha-blocker.

Acebutolol↗
PubMed1982

Synchronization of oestrus in ewes with Provera sponges/PMSG, prostaglandin F2 alpha or the prostaglandin analogue, ICI 80996, and fertility following natural mating or artificial insemination.

Following the synchronization of oestrus with different treatments during the breeding season, the fertility of naturally-mated ewes has been compared to that of ewes artificially inseminated with fresh semen. The following treatments were used: I. sponges impregnated with progestagen (50--60 mg of medroxyprogesterone acetate) left in situ for 14 days and an i.m. injection of 500 IU of PMSG at sponge withdrawal; II. injections of prostaglandin F2 alpha (dose: 15 mg/injection) at intervals varying from 9 to 14 days (see tables); III. injections of the prostaglandin F2 alpha analogue, ICI 80996 (dose: 100 micrograms/injection), with the same time intervals as in treatment II. Lambing rate and prolificacy after natural service at the induced oestrus was 55 and 140 p. 100, 32.5 and 153 p. 100 and 60 and 133 p. 100 for ewes receiving treatments I, II or III, respectively, compared to 62.5 and 120 p. 100 for the untreated controls. Double artificial insemination (AI) 48 and 58 h after the sponge/PMSG treatment resulted in a lambing rate of 25 p. 100 and a prolificacy of 133 p. 100. The lambing rate and prolificacy of ewes inseminated 58 and 68 h after the final injection of PGF2 alpha or ICI 80996 were 27.8 and 149 p. 100 and 45.5 and 165 p. 100, respectively. Single AI 55 h after sponge withdrawal gave a lambing rate of 37.8 p. 100. The lambing rate of ewes inseminated 56 h after the final ICI 80996 injection was higher (54.8 p. 100) than that of ewes inseminated at 60 h (37.5 p. 100) or 66 h (30.8 p. 100). However, two inseminations 56 and 66 h after the final ICI 80996 injection gave an even more elevated lambing rate (61.9 p. 100). These results demonstrate that ICI 80996 can successfully control oestrus in the ewe during the breeding season, thus offering an alternative to sponges/PMSG and that the fertility subsequent to both natural mating and AI is equivalent to that of the controls.

Animals↗