Expression and biological activity of parathyroid hormone-related peptide in pregnant rat uterine artery: any role for 8-iso-prostaglandin F2alpha?

PTHrP is produced in vessels and acts as a local modulator of tone. We recently reported that PTHrP(1-34) is able to induce vasorelaxation in rat uterine arteries, but in pregnancy, this response is blunted and becomes strictly endothelium dependent. The present study aimed to get insights into the mechanisms involved in these changes because the adaptation of uterine blood flow is essential for fetal development.

[Which basal tension for the study of aortic reactivity in pregnant Wistar rats?].

Basal tension for optimal contraction either for a maximal contraction in pregnant Wistar rat is not well know. Our study aims to determinate the optimal basal tension for the study of aortic contraction in pregnant Wistar rat. The stability of vessels tone depending on basal tension was also determinate.

[Endothelium-dependent relaxation of Wistar rat aorta in late pregnancy].

Some authors usually described an enhanced vascular reactivity to vasodilatoragents during pregancy. We would like toverifythis hypothesis with acetylcholin which is the vasodilator agent habitually used in animal experimentation. Young adult Wistar rats, pregnant and nonpregnant, were used.

Parathyroid hormone-related protein-induced relaxation of rat uterine arteries: influence of the endothelium during gestation.

Objective: Parathyroid hormone-related protein (PTHrP) has been reported to relax different vessels. We investigated the influence of both endothelium and gestation on the relaxation of uterine arteries (UA), which supply blood to myometrium and placenta.

Methods: Small uterine and mesenteric arteries (MA) with (E+) and without endothelium (E-) from day 20 pregnant (P) and nonpregnant (NP) rats were mounted in a myograph, precontracted with phenylephrine (PE) in a physiologic salt solution.

Effect of i1 imidazoline receptor agonist, moxonidine, in nitric oxide-deficient hypertension in pregnant rats.

Decreased nitric oxide production has been reported in preeclampsia, which is also frequently associated with glucose intolerance. It was thus considered of interest to investigate the effects of moxonidine, a centrally acting antihypertensive drug that reduces insulin resistance, in a rat model of preeclampsia. Hypertension was induced in Wistar rats by dietary l-NNA (N(omega)-nitro-L-arginine, 0.

Extracellular calcium level is crucial for aortic contractile response in pregnant rat.

Studies of vascular reactivity during late pregnancy were performed to investigate the previously described hyporeactivity to vasopressors. Two groups of seven control (nonpregnant) and seven late pregnant (day 20) Wistar rats were used. Rubbed (E-) segments from thoracic aorta were studied for contractile studies in a Krebs solution containing either 1.

Maturation reveals a decrease in endothelium-dependent contraction induced by depolarization in the aorta of spontaneously hypertensive rats.

The influence of the endothelium on aortic contractility to KCl 100 mM was studied during maturation and aging in normotensive Wistar and spontaneously hypertensive rats (SHR). In Wistar rats, there was no significant difference in maximal responses in the course of aging whether the endothelium was present (E+) or not (E-). A similar result was obtained in SHR E- rings.

Effects of sufentanil and NMDA antagonists on a C-fibre reflex in the rat.

The effects of intravenous sufentanil and pre-administration of N-methyl-D-aspartate (NMDA) receptor antagonists were tested on a reflex triggered by C-fibre activation. The reflex was elicited by electrical stimulation of the sural nerve and recorded from the ipsilateral biceps femoris muscle in halothane anaesthetized rats either (1) with an intact neuraxis or (2) in which the brain had previously been transected at the level of the obex. All four doses of sufentanil (0.

Hypotensive effect of endothelin-1 in nitric oxide-deprived, hypertensive pregnant rats.

Both nitric oxide (NO) and endothelin-1 (ET-1) are important mediators in the regulation of vascular tone during pregnancy and preeclampsia. This study was designed to investigate the ET-1-induced hypotensive effect in late pregnant rats (P) and in NO-deprived hypertensive pregnant rats (TP), a model of preeclampsia. From day 13 of pregnancy Wistar rats were fed a control or an N(omega)-nitro-L-arginine-enriched diet.

Monitoring plasma levels of ganciclovir in AIDS patients receiving oral ganciclovir as maintenance therapy for CMV retinitis.

Objectives: To investigate whether low ganciclovir serum levels in patients on maintenance oral ganciclovir therapy are associated with recurrence of CMV retinitis.

Methods: A prospective study of the plasma concentration of ganciclovir after initiation of maintenance oral ganciclovir therapy in 14 AIDS patients who had recovered from acute cytomegalovirus (CMV) retinitis.

Results: Five of the 14 patients exhibited a mean time to recurrence of 37 days.

Endothelium and aortic contraction to endothelin-1 in the pregnant rat.

Endothelium-derived factors modulate tone and may be involved in hyporeactivity to vasoconstrictors, such as norepinephrine or angiotensin II, as has been previously described during gestation. The endothelium produces endothelin-1, a major vasoconstrictor peptide, therefore aortic contractions to endothelin-1 (10(-10) to 3 x 10(-7) M) were used to assess the role of the endothelium in pregnant Wistar rats (at 20 days of gestation). Late pregnancy is characterized by a significantly diminished systolic blood pressure in conscious rats (-17 mmHg, P < 0.

[Nitric oxide and isolated aortic contraction in a pregnant hypertension model by the inhibition of nitric oxide synthase in pregnant Wistar rats].

During gestation endothelium induces decreases in vascular responses to vasopressor agents but endothelium disease is followed by hypertension and enhanced vascular reactivity during preeclampsia. In a rat model of preeclampsia induced by NO synthase inhibition we study here isolated aortic contractions. From day 13 of gestation 2 groups of Wistar female rats were fed control (C) or nitro-arginine enriched diets (0.

Endothelin-1 and relaxation of the rat aorta during pregnancy in nitroarginine-induced hypertension.

In pregnant rats during hypertension induced by NO synthase inhibition, endothelin (ET) plasma levels are increased as in some preeclamptic women. Previously, the enhanced vasodepressor effect of endothelin-1 (ET-1) has been observed in this model, thus we decided to study the relaxation induced by ET-1 on the aorta. Non-pregnant or pregnant Wistar rats (n = 7 by group) were fed for 7 days (day 13-day 20) on a nitroarginine-enriched diet (L-NNA, 0.

[Hypotensive effect of endothelin-1 in a rat model of pre-eclampsia].

Hypertensive pregnant rats with inhibition of NO synthase are frequently considered as model of pre-eclampsia with proteinuria, hypertension and elevated endothelin (ET-1) blood levels. We describe here the cardiovascular in vivo effects of ET-1 in this rat model since ET-1 and NO are both important vasoactive mediators in uteroplacental circulation. From day 13 of gestation 2 groups of Wistar female rats were fed control (C) or nitroarginine enriched diet (0.

[Epinephrine stability in solutions for intra-ocular irrigations].

Purpose: Epinephrine may be used for ocular irrigation during ophthalmic surgery when diluted in balanced saline solutions. In aqueous solution, epinephrine breakdown depends on pH, light, temperature, oxidating agents and increases with time.

Methods: The stability of epinephrine in plastic bags prepared in low concentrations (1 mg/L) was studied by HPLC analysis with UV detection, completed with pH determinations, performed after storage (protected from light) in various conditions: at room temperature (+25 degrees C), at +4 degrees C (in a refrigerator), at -20 degrees C (in a freezer).

Blood pressure effects of calcium intake in experimental models of hypertension.

Calcium intake has been implicated as being an important factor in the development and treatment of hypertension. The mechanisms underlying the relationship between calcium and blood pressure are not yet clearly defined. Experimental studies have documented an inverse association between calcium intake and blood pressure level.

Endogenous nitric oxide is not involved in acute parathyroid hormone-induced hypotension in rat: effect of hypertension and hypoparathyroid status.

The present study investigated the acute hypotensive effect of parathyroid hormone (PTH) in anesthetized adult spontaneously hypertensive (SHR) and normotensive Wistar-Kyoto rats. Furthermore, in order to determine the possible contribution of nitric oxide (NO), a mediator of endothelium-dependent vasorelaxation, hypotensive responses to PTH were obtained in the presence of NG-nitro-L-arginine methyl ester (L-NAME), an inhibitor of NO synthesis. The hypotensive effect of PTH (expressed as % of baseline blood pressure) was similar for the two strains.

[Chronic and acute effect of cycletanine in NO-dependent hypertensive pregnant rats].

Decreased response to vasopressor agents characterizes pregnancy. Endothelium-derived relaxing factors and vasodilating prostaglandins play an important role in the vascular tone during pregnancy. Since inhibition of nitric oxide (NO) biosynthesis induced by NO2-arginine enriched diet produced hypertension we measured in vivo cardiovascular responses to PGF2 alpha, L-arginine (L-arg) and cicletanine (Cic, IPSEN, France) which enhances PGI2 production.

Pharmacokinetics of the enantiomers of tertatolol in the rat after oral and intravenous administration.

1. Plasma concentrations of the two enantiomers of tertatolol were determined by gc/ms. Deuterium labelling of one of the tertatolol enantiomers was used for chiral discrimination.

Ions, parathyroids, and genetic hypertension.

Several reports suggested an involvement of parathyroid function in blood pressure regulation in animals and humans: hyperparathyroid subjects frequently display an elevated systolic blood pressure and young mild hypertensive patients show enhanced serum PTH levels. Moreover, removal of parathyroid glands (PTX) in young rats attenuates and delays the development of mineralocorticoid and genetic hypertension. In addition, in vivo cardiovascular reactivity to norepinephrine in PTX rats from both spontaneously the hypertensive rat (SHR) and Lyon hypertensive rat (LH) strains is decreased, as is calcium content in aortic and heart fragments.

Characterization of endothelium-derived relaxing factor involvement in the potentiating effect of parathyroidectomy on norepinephrine-induced rat aortic contraction.

Previous results have shown that the contractile response to norepinephrine (NE) was enhanced in isolated aortae from SHR and normotensive Wistar parathyroidectomized rats. In this work we sought to characterize the contribution of endothelium-derived relaxing factor (EDRF) release to this effect which is not linked to hypertension. Parathyroidectomy (PTX) was performed by surgery on 5 week-old male Wistar rats.

Parathyroid cross-transplantation and development of high blood pressure in rats.

To clarify further the relationships between parathyroid glands and the development of hypertension, we studied the effect of cross-transplantation of these glands from young hypertensive rats in normotensive recipients. The parathyroid glands were isolated in 5-week-old hypertensive rats of the Lyon (male and female) and Milan (only male) strains and immediately grafted into the corresponding, just parathyroidectomized normotensive rats of the same age. Control rats were either sham-operated or grafted with the glands of the same normotensive strain.

Endothelium-derived relaxing factor, hypertension and chronic parathyroidectomy in spontaneously hypertensive and Wistar-Kyoto rats.

1. Parathyroidectomy (PTX) lessens the development of hypertension in young spontaneously hypertensive rats (SHR) and the involved mechanisms remain to be elucidated. We have studied here the aortic vascular reactivity to both norepinephrine (NE) and acetylcholine in 10 week old male PTX SHR and Wistar-Kyoto (WKY) rats.

[Genetic hypertension in the rat is partially dependent of parathyroid glands. Results of a crossed transplantation trial].

The parathyroid hypertensive factor (PHF) is present in the plasma of SHR rats. The authors of this study set out to determine whether this factor was also present in the Lyon (LH male and female) and Milan (MHS male) hypertensive rats. Five week old normotensive rats (LN and MNS) were transplanted with the parathyroid glands of LH and MHS rats immediately after parathyroidectomy (PTX).

Age, endothelium and aortic reactivity to calcium in Wistar rat.

The influence of age from (9 to 72 weeks) was investigated on contractions elicited by calcium in Wistar rat aortic rings with and without endothelium. The arteries were either depolarized by KCl or exposed to Bay K 8644 and concentration-effect curves to cumulative additions of CaCl2 were constructed. Whether the endothelium was present or not, the potency of CaCl2 but not its maximal effect decreased with age.