Effects of estrogen and progesterone on adrenoceptors and cyclic nucleotides in rat uterus.

Kaburagi, Takashi

doi:10.1254/jjp.32.535

Cited by 22 publications

(4 citation statements)

References 22 publications

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“…In addition, isoproterenol did not alter E max following progesterone treatment even if estrogen was administered simultaneously. In rat uterus (Kano 1982) and guinea pig myometrium (Hatjis et al 1988) progesterone up-regulates -adrenergic receptors. Taken together, this suggests that progesterone favors uterine quiescence both directly via regulation of -adrenoceptors and indirectly through the inhibition of the influence of estrogen on the receptors.…”

Section: Discussionmentioning

confidence: 99%

Desensitization of beta2-adrenoceptor function in non-pregnant rat myometrium is modulated by sex steroids

Engstrøm

Vilhardt²,

Bratholm³

et al. 2001

Journal of Endocrinology

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The effects of in vivo treatment with estrogen and progesterone on isoproterenol-induced uterine relaxation and 2 -adrenoceptor ( 2 AR) mRNA production in nonpregnant rat myometrium were investigated. Whether homologous myometrial desensitization of 2 AR function was dependent on or modulated by the two steroids was also examined.Estrogen treatment alone or in combination with progesterone reduced maximal relaxation (E max ) of isolated uterine strips subsequently challenged with isoproterenol whereas progesterone alone had no effect on this parameter. The reduction was accompanied by an enhanced 2 AR mRNA concentration. The concentration of isoproterenol giving half-maximal relaxing response (EC 50 ) increased following estrogen treatment and this effect was curbed by progesterone.Isoproterenol had no effect on 2 AR transcription irrespective of the steroid regimes employed. E max of isolated uterine strips was reduced following prolonged in vivo treatment with isoproterenol but the effect was found only when estrogen alone was administered concomitantly. Finally, in vivo treatment with isoproterenol increased EC 50 of uterine strips subsequently stimulated with isoproterenol in vitro. This effect was independent of steroid treatment.We conclude that homologous desensitization of 2 AR function in non-pregnant rat myometrium in terms of sensitivity (EC 50 ) is independent of sex steroids but in terms of maximal response (E max ) occurs only in the presence of estrogen. We speculate whether progesterone withdrawal in connection with the well-known estrogen dominance at rat parturition may strengthen the desensitization induced by 2 AR activation and thus contribute to the transformation of the uterus from a quiescent to a highly contractile organ.

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Section: Discussionmentioning

confidence: 99%

Desensitization of beta2-adrenoceptor function in non-pregnant rat myometrium is modulated by sex steroids

Engstrøm

Vilhardt²,

Bratholm³

et al. 2001

Journal of Endocrinology

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“…The precise mechanisms by which ovarian steroid hormones modulate adrenoreceptormediated responses of smooth muscle of the reproductive tract remain uncertain. To our knowledge, there have been no studies of the effects of steroid treatments upon the binding of radioligands to the adrenoreceptors of uterine membranes from the guinea-pig, although similar studies have been conducted using preparations from the rat (Krall, Mori, Tuck, Le Shon & Korenman, 1978;Kano, 1982) and the rabbit (Roberts, Insel, Goldfien & Goldfien, 1977;Williams & Lefkowitz, 1977;Hoffman, Lavin, Lefkowitz & Ruffolo, 1981;Roberts, Insel & Goldfien, 1981). The radioligand binding studies using rabbit myometrial membranes have been interpreted as demonstrating an increase in the number of a-adrenoreceptors following oestrogen treatment, with progesterone treatment preventing such an increase (Roberts et al, 1981).…”

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confidence: 99%

Effects of Adrenaline and Noradrenaline in Separated Longitudinal and Circular Myometrial Preparations From the Guinea‐pig: Selective Modulation by Ovarian Steroids

Adam

Hartley

Pennefather

et al. 1984

Journal of Autonomic Pharmacology

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Field-stimulated strips of circular and longitudinal myometrium from virgin adult guinea-pigs were used to study the influence of ovarian steroids upon uterine responses to adrenaline and noradrenaline. Preparations were taken from animals (i) untreated, on day 9 or 10 of the oestrous cycle; (ii) treated for 14 days with oestradiol cypionate, beginning on day 9 or 10; and (iii) treated as in (ii) then given both oestradiol cypionate and progesterone for a further four days. Oestradiol treatment led to a 2-fold increase in the circulating level of progesterone; subsequent treatment of oestradiol-primed animals with progesterone resulted in even higher circulating progesterone levels, comparable with those occurring during mid-pregnancy in this species. Both adrenaline and noradrenaline produced phentolamine-sensitive motor responses of circular myometrial preparations from each treatment group. Steroid treatment was without significant effect on the potencies or maximal effects of the two amines on the circular muscle layer. Both catecholamines effected phentolamine-sensitive excitatory responses of longitudinal myometrial preparations from untreated guinea-pigs. Adrenaline usually produced propranolol-sensitive inhibitory responses of longitudinal preparations from oestradiol-treated animals, while noradrenaline did so only in a minority of cases. The potencies of adrenaline as an inhibitory agonist and noradrenaline as an excitatory agonist were markedly increased in preparations from oestradiol-primed animals.(ABSTRACT TRUNCATED AT 250 WORDS)

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“…Intrathecally injected OT recruits autonomic pathways, which relay in the paracervical ganglion and release a variety of neurotransmitters in the uterus (35). It has been shown that the affinity and/or number of uterine receptors for neurotransmitters of the autonomic nervous system change along the estrous cycle in rats (3,4,14,16,35). This variable sensitivity of the receptive organ may contribute to explain the differential effects of intrathecal OT at the various stages.…”

Section: Discussionmentioning

confidence: 99%

Spinal effects of oxytocin on uterine motility in anesthetized rats

Benoussaidh¹,

Maurin²,

Rampin³

2004

American Journal of Physiology-Regulatory, Integrative and Comp

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Benoussaidh, Anissa, Yves Maurin, and Olivier Rampin. Spinal effects of oxytocin on uterine motility in anesthetized rats. Am J Physiol Regul Integr Comp Physiol 287: R446 -R453, 2004. First published March 25, 2004 10.1152/ajpregu.00117.2004.-The rat uterus receives an innervation from the lumbosacral and thoracolumbar segments of the spinal cord. These segments receive descending oxytocinergic projections from the paraventricular nucleus of the hypothalamus. We tested the hypothesis that oxytocin regulates uterine motility through a spinal site of action. Oxytocin was administered in anesthetized female rats either intrathecally at the lumbosacral or thoracolumbar spinal cord levels or intravenously. Uterine activity was revealed by measuring changes of intrauterine pressure using an indwelling balloon placed in one caudal uterine horn. The uterus displayed a spontaneous activity characterized by intrauterine pressure rises, the frequency, amplitude, and duration of which were dependent on the stage of the estrous cycle. Oxytocin delivered at the lumbosacral level affected the frequency (during proestrus, estrus, and diestrus) and amplitude (during proestrus and estrus) of uterine activity. During estrus, oxytocin delivered at the thoracolumbar level affected the frequency, amplitude, and duration of the intrauterine pressure rises. Intravenous oxytocin not only affected intrauterine pressure rises (namely amplitude during proestrus and estrus and frequency and duration during estrus) but also increased the basal tone during estrus. The effects of lumbosacral oxytocin were partly mimicked by the oxytocin agonist [Thr 4 ,Gly 7 ]-oxytocin blocked by the oxytocin receptor antagonist atosiban and by hexamethonium. Arginine vasopressin delivered at the lumbosacral level had no effect. These results support our hypothesis that oxytocin released by descending paraventriculo-spinal pathways and acting on spinal oxytocin receptors modulates the activity of the uterus. This regulation is cycle dependent. urogenital; lumbosacral spinal cord; sexual reflexes OXYTOCIN (OT) exerts peripheral contractile effects on the uterus after its release into the systemic circulation by magnocellular neurons of the paraventricular nucleus (29). In addition to this endocrine mode of action, OT may also be released at various levels of the brain stem and spinal cord by paraventriculo-spinal projections originating in parvocellular neurons of the paraventricular nucleus (5,25,28,30,31,33). In the brain stem, this pathway activates motoneurons of the dorsal motor nucleus of the vagus to increase gut motility (6). In the dorsal horn of the spinal cord, OT has been suggested to have antinociceptive effects through the modulation of glutamate release (13). At the lumbosacral level, this pathway has been shown to elicit penile erection in male rats (8) and to participate in the control of bladder activity in female rats (19). Whether OT released at the lumbosacral level affects uterine motility (and to what extent) remained to be shown.Uteri...

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Effects of estrogen and progesterone on adrenoceptors and cyclic nucleotides in rat uterus.

Cited by 22 publications

References 22 publications

Desensitization of beta2-adrenoceptor function in non-pregnant rat myometrium is modulated by sex steroids

Desensitization of beta2-adrenoceptor function in non-pregnant rat myometrium is modulated by sex steroids

Effects of Adrenaline and Noradrenaline in Separated Longitudinal and Circular Myometrial Preparations From the Guinea‐pig: Selective Modulation by Ovarian Steroids

Spinal effects of oxytocin on uterine motility in anesthetized rats

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