Effects of newly synthetized isoquinoline derivatives on rat uterine contractility and ROCK II activity

Protein kinases have an important role in signal transduction in the cellular system via protein phosphorylation. RhoA activated Rho-kinases have a pivotal role in the regulation of smooth muscle contraction. ROCK I and ROCK II phosphorylate myosin-phosphatase and myosin-kinase, which induces contraction in the myometrium. Several studies have investigated the affinity of isoquinoline alkaloids (HA-1077, H1152P) to Rho-kinases, and these compounds notably inhibited the Ca²⁺-independent process. We measured the efficiency of 25 original, newly synthesized isoquinoline derivatives for the Rho-kinase activity using Rho-associated kinase activity assay and determined their effects on the non-pregnant, 20-day pregnant and parturient rat myometrial contraction in vitro. The IC₅₀ values of 11 from among the 25 derivatives were significantly lower on the oxytocin-induced non-pregnant rat uterine contraction compared with Y-27632 and fasudil, although their maximal inhibitory effects were weaker than those of Y-27632 and fasudil. We measured the effects of 11 isoquinoline molecules with significant IC₅₀ values on ROCK II activity. We found two isoquinolines out of 11 compounds (218 and 852) which decreased the active ROCK II level similarly as Y-27632. Then we found that 218 and 852 relaxed the 20th-day pregnant and parturient rat uterus with greater potency as compared with fasudil. The majority of the synthesized isoquinoline derivatives have uterus relaxant effects and two of them significantly suppress the Rho-kinase mediated myosin light chain phosphorylation. Our results may suggest that the isoquinoline structure has a promising prospect for the development of new and effective inhibitors of uterine contractions in preterm birth.

Alteration in expressions of RhoA and Rho-kinases during pregnancy in rats: their roles in uterine contractions and onset of labour

Activation of RhoA and Rho-associated kinases (ROCKs) is known to play a pivotal role in the regulation of smooth muscle contraction via phosphorylation of myosin-light chain and myosin phosphatase. There are few data on the RhoA and ROCKs expression levels in rat uteri. Therefore, our aim was to investigate the mRNA and protein concentration of RhoA and ROCKs in rat uterus during pregnancy, during parturition and post-partum using real time PCR and Western blot analysis. The other purpose was to evaluate the effects of the ROCK (Y-27632, fasudil and RKI 1441) and RhoA inhibitors (simvastatin) on uterine contractility in isolated organ bath experiments. The mRNA and protein levels of RhoA decreased on the 5th day of pregnancy to day 22, then a sharp increase was detected at term. The mRNA and protein concentration of ROCKs was down-regulated in the early stage of pregnancy, while it sharply increased during parturition. The RhoA-inhibitor simvastatin relaxed the uterus contractions, although its inhibitory effects were not followed by the alteration of RhoA. The strongest inhibitory effect of non-selective ROCK inhibitor fasudil was found on non-pregnant uterus, while it elicited milder relaxation on day 22, during parturition and postpartum day 1. The maximum relaxing effects of Y-27632 and RKI 1441 were altered in a proportional way with the target protein expressions. The RhoA/ROCK signalling pathway might be a potential target for the development of new tocolytic agents; however, high specificity to RhoA, ROCK I or ROCK II seems to be fundamental to the high efficacy of uterine relaxation.

Ontogeny of sulfonylurea-binding regulatory subunits of K(ATP) channels in the pregnant rat myometrium

ATP-sensitive potassium channels (K(ATP) channels) are composed of sulfonylurea receptors (SURs) and potassium inward rectifiers (Kir(6.x)) that assemble to form a large octameric channel. This study was designed to examine the expression and role of sulfonylurea-binding regulatory subunits 1 (SUR1 (ABCC8)) and 2 (SUR2 (ABCC9)) of the K(ATP) channels in the pregnant rat myometrium with particular regard to the contractility. RT-PCR and western blot analyses were performed to detect the presence of SUR1 and SUR2. The SUR1 levels were markedly increased in the early stages of pregnancy. The highest level was detected on day 6 of pregnancy, whereas in the late stages, the levels of SUR1 were significantly decreased. The SUR2 level remained unchanged throughout pregnancy. The SUR non-selective diazoxide and the SUR2-selective pinacidil inhibited oxytocin-induced contractions. Glibenclamide, a K(ATP) channel blocker, antagonized both pinacidil- and diazoxide-induced relaxations. It was established that SURs are responsible for pharmacological reactivity of K(ATP) channel openers. We conclude that both SURs are involved in the K(ATP) channel in the pregnant rat myometrium. It may further be concluded that 'pinacidil-like' K(ATP) channel openers may be of therapeutic relevance as tocolytic agents in the future.

The effects of adjuvant arthritis on the myometrial adrenergic functions in the nonpregnant and the late-pregnant rat

The beneficial effects of pregnancy on the symptoms of inflammatory diseases are well documented. The modulation in the uterine functions in the presence of generalized inflammation, however, is much less characterized. The aim of the present study was to explore the modulatory action of adjuvant arthritis on the adrenergic functions of the uterus in nonpregnant and late pregnant rats. Adjuvant arthritis was induced by the subplantar injection of M. butyricum. Presynaptic functions were characterized by a superfusion technique and by registration of the contractions of isolated uterine rings elicited by electric field stimulation. The functions of the adrenoceptors were characterized by constructing concentration-response curves with agonists for both α- and β-receptors. Where these curves differed significantly from the control, the expressions of these receptors at the mRNA level were additionally determined. Adjuvant arthritis substantially decreased the uptake and release of [(3)H]noradrenaline in myometrial samples from nonpregnant rats, but caused no change at term. The electrically induced contractions were decreased by inflammation in both gestational states. Arthritis resulted in decreased β-adrenoceptor-mediated relaxation (in both the nonpregnant and the late-pregnant animals) and an increase in α-mediated contraction at term. It can be concluded that adjuvant arthritis deteriorates the adrenergic innervation of the uterus. The effects of exogenous sympathomimetics are shifted, favoring a state of higher contractility. If similar mechanisms are operative in humans, the present results could imply that β-adrenoceptor agonists are not ideal tocolytics when pregnancy is complicated by generalized inflammation.

Nociceptin inhibits uterine contractions in term-pregnant rats by signaling through multiple pathways

The actions of the endogenous peptide nociceptin (PNOC; previously abbreviated as N/OFQ) on the myometrium have not been investigated previously. Our aim was to study the presence and functional role of PNOC in the modulation of uterine contractility in pregnant rats at term. The presence of PNOC and its receptors (OPRL1; previously called NOP) in the uterus were detected by radioimmunoassay and radioligand-binding experiments. The PNOC-stimulated G protein activation was assessed by a [(35)S]GTPgammaS-binding technique. The effects of PNOC in uterine rings precontracted with KCl or oxytocin were also tested in vitro. Uterine levels of cAMP were measured by enzyme immunoassay. The K(+) channel blockers tetraethylammonium and paxilline were used to study the role of K(+) channels in mediating the uterine effects of PNOC. Both PNOC and OPRL1 were present in the uterus. PNOC revealed a maximum contraction inhibition of approximately 30%, which was increased to 40% by naloxone. Naloxone and pertussis toxin significantly attenuated the G protein-stimulating effect of PNOC. The uterine cAMP levels were elevated by PNOC and naloxone and after preincubation with pertussis toxin. Tetraethylammonium and paxilline reduced the contraction-inhibiting effect of PNOC and naloxone to approximately 10% and 15%, respectively. We presume that PNOC plays a role in regulating uterine contractility at term. Its effect is mediated partly by stimulatory heterotrimeric G (G(s)) proteins coupled to OPRL1 receptors and elevated cAMP levels, and also by Ca(2+)-dependent K(+) channels. Our results demonstrate a novel action and signaling pathway for PNOC that might be a potential drug target.

In vitro and in vivo investigations on the binary meloxicam-mannitol system

The objective of the study in rats was to investigate the anti-inflammatory effects of pure meloxicam (ME) with different particle sizes and of physical mixtures of the binary ME-mannitol system. The level of local inflammation was significantly decreased when the amount of mannitol was the highest and the particle size of ME was the lowest as well as the components had the interparticulate interaction. The same results were achieved in in vitro experiments.

Effects of streptozotocin-induced diabetes on the uterine adrenergic nerve function in pregnant ratsA superfusion study

Pregnancy-induced diabetes mellitus poses one of the greatest challenges in obstetrical practice. The direct action of diabetes on the myometrial adrenergic functions has not been completely characterized. Accordingly, the present study relates to the impact of experimentally induced diabetes on the presynaptic functions of the rat uterus in relation to gestational age. Experiments were carried out on non-pregnant, early-pregnant (day 7), middle-pregnant (day 14) and late-pregnant (day 21) animals. Diabetes was induced with streptozotocin (60 mg/kg, i.v.) in virgin female or early-pregnant animals (on day 2 for the day 7 experiments and on day 5 for the experiments on the middle and late-pregnant animals). Myometrial samples were utilized for superfusion experiments. After saturation, [3H]noradrenaline perfusate fractions were collected and electric field stimulation was applied to determine the amount of transmitter liberated. Additionally, the total uptake capacity of each sample was assayed. Experimental diabetes decreases the transmitter uptake capacity both in virgin rats and at all stages of pregnancy. In early pregnancy (on day 7), this limitation in uptake is obvious as early as 5 days after the induction of diabetes. In non-pregnant animals, the electrically stimulated transmitter release is inhibited substantially, a similar decrease being observed only at mid-pregnancy (day 14). The present superfusion study proves that experimental diabetes depresses the presynaptic adrenergic functions (both the transmitter uptake and the stimulated release) in the myometrium of the rat. Since the effect of diabetes on the uptake capacity can be detected earlier than for generally accepted markers of peripheral neuropathies, superfusion can be suggested as a sensitive and reliable approach for investigations of hyperglycaemia-related functional deteriorations. We speculate that diabetes-induced functional deterioration of the adrenergic nerves could partially explain the anomalies of the reproductive functions found in diabetic patients if a similar mechanism is operative in humans.

WITHDRAWN: Effects of diabetes on the uterine adrenergic nerve function in pregnant rats. A superfusion study

The Publisher regrets that this article is an accidental duplication of an article that has already been published in Neurochemistry International, doi:10.1016/j.neunet.2005.10.001. The duplicate article has therefore been withdrawn.

Effect of Avemar--a fermented wheat germ extract--on rheumatoid arthritis. Preliminary data

OBJECTIVE

To investigate the effect of the fermented wheat germ extract (Avemar)in patients with severe rheumatoid arthritis (RA).

METHODS

Fifteen female RA (Steinbrocker II-III) patients, who had unsuccessfully tried two different DMARD treatments, were enrolled in an open-label, 1-year long, pilot clinical study. DMARD and steroid therapies were recorded and continued. All patients received Avemar as additional therapy. For measurement of efficacy the Ritchie Index, the Health Assessment Questionnaire (HAQ) and the assessment of morning stiffness were applied. Patients were evaluated at baseline, 6 and 12 months. For statistical analyses the Wilcoxon test was used.

RESULTS

At both 6 and 12 months, Ritchie index, HAQ and morning stiffness showed significant improvements compared with the baseline values. Dosages of steroids could be reduced in about half of the patients. No side effects of Avemar were observed.

CONCLUSION

Supplementation of standard therapies with a continuous administration of Avemar is beneficial for RA patients.

A rat model for functional characterization of pregnancy-induced denervation and postpartum reinnervation in the myometrium and cervix: a superfusion study

The pregnancy-induced rapid degeneration of the adrenergic nerves innervating the uterus is a well-known but poorly understood phenomenon. Since most of the published investigations were carried out by histological assay, our aim was to describe the loss of the adrenergic function during pregnancy and the reinnervational procedure in the postpartum period. Myometrial and cervical samples from rats were loaded with [3H]noradrenaline and then transferred into a chamber for superfusion. After a wash-out period, fractions were collected. The fifth and fifteenth fraction tissues were stimulated with an electric field. The [3H]noradrenaline contents of the fractions were determined, together with the amount remaining in the tissue. The myometrial [3H]noradrenaline release was substantially decreased in early pregnancy, and absent in the late stage. Differences in release profile were detected between the implantation sites and the interimplantation areas. As a refinement of the results of previous histochemical studies, the noradrenergic functions of the cervix were found to be deeply affected in the early postpartum period. The pregnancy-induced denervational procedure can be followed by means of a superfusional technique after [3H]noradrenaline loading. As our technique is considered to be similar in sensitivity to histological methods, superfusion can be regarded as a model for functional investigations of pregnancy-induced denervation.

Topical absorption of piroxicam from organogels—in vitro and in vivo correlations

In view of their good skin tolerability, glyceryl fatty acid esters were used as organogelators, and their effects in the topical penetration of piroxicam (Px) were investigated. The in vivo skin penetration was evaluated by measuring the anti-inflammatory effect in rats, where we found that Px incorporated into glyceryl fatty acid ester organogels exhibited a significantly greater inhibition of oedema than that of the placebo control either when applied locally (p < 0.001), or via transdermal absorption (p < 0.01 and < 0.05, respectively). As the Px concentration was increased, the extent of oedema inhibition rose in accordance with a power law. Comparisons with traditional galenic organogels and a marketed product revealed that the relative biological availability of Px was better from glyceryl fatty acid ester organogels, except when calculated for D1 versus T2 and T3. In order to predict the extent of in vivo skin absorption, we measured the penetration coefficient and the in vitro penetration. In accordance with theory, the extent of in vivo oedema inhibition increased as P(oct/w) increased, and maximum inhibition was observed at logP = 2.0211. However, the in vitro penetration through a synthetic membrane did not correlate with the in vivo results, the reason for which might be the different natures of the model barriers.

Iron(II) sulfate release from drop-formed lipophilic matrices developed by special hot-melt technology

Iron(II) sulfate-containing lipophilic matrices were developed by a special hot-melt technology (melt solidification in drops), using stearin, white wax and their mixture as conventional bed materials. The special technology resulted in spherical particles which can be filled directly into capsules; these store iron as a depot and ensure a slow and uniform release, whereby the irritation of the gastric mucosa by the iron can be decreased. The rates of dissolution of the iron(II) sulfate from the various lipophilic matrices were different, but fundamentally low. Kinetic calculations demonstrated that the rate of dissolution of the iron(II) sulfate was of approximately zero kinetic order. The results of in vivo experiments on rabbits correlated well with the in vitro data. The plasma curves for the animals treated with the iron(II) sulfate preparations varied with the excipients in the depot products. The properties and ratio of the bed materials influenced the release of the iron(II) sulfate. In all probability, the release of the active agent can be regulated through the use of a melt of stearin and white wax in different ratios. The development products functioned as a sustained-release system and ensured elimination of the irritation of the gastric mucosa. At the same time, the results justified the applicability of the special hot-melt technology in the development of the solid dosage form.

Synergism between beta 2-adrenoceptor agonists and subtype-selective alpha 1A-adrenoceptor antagonists in the tocolytic effect on pregnant rat uterus in vitro

1. Despite great efforts in recent decades, premature birth is still a leading cause of perinatal morbidity and mortality. beta2-Adrenoceptor agonists are frequently used as tocolytics, although their use is rather controversial. Previous animal studies have revealed that blockade of alpha1A-adrenoceptors results in relaxation of the pregnant rat myometrium. 2. The aim of the present study was to investigate the uterus relaxant effect of the beta2-adrenoceptor agonists (terbutaline, ritodrin) applied together with the subtype-selective alpha1A-adrenoceptor antagonists (WB 4101, 5-methylurapidil) in an in vitro rat model. The main objective of the experiments was to clarify whether there was an additive or a potentiating synergism between the two drug classes. 3. Myometrial rings were taken from female, 22-day pregnant (end-term) Sprague-Dawley rats. Electrical field stimulation (EFS) was used to elicit rhythmical contractions. Non-cumulative concentration-response curves were constructed to the beta2-adrenoceptor agonists and the alpha1A-adrenoceptor antagonists alone and to beta2-adrenoceptor agonists co-administered with the alpha1A-adrenoceptor antagonists. 4. Both groups of drugs inhibited EFS-induced contractions in a dose-dependent way. Administering the beta2-adrenoceptor agonists in combination with the alpha1A-adrenoceptor antagonists resulted in a significant decrease in the EC50 and an increase in the maximal contraction inhibiting effect. 5. The potentiating synergism that has been revealed between beta2-adrenoceptor agonists and alpha1A-adrenoceptor antagonists in the uterus relaxant effect may be of great clinical importance because it could improve the efficacy of therapy of preterm delivery.

Noncompetitive nature of oxytocin antagonists with general structure Mpa(1)Xxx(2)Sar(7)Arg(8)

Eight oxytocin (OT) antagonists with general structure Mpa(1)Sar(7)Arg(8), substituted at position 2 with conformationally constrained and bulky amino acids, were synthesized and pharmacologically tested. Binding affinities and selectivities of compounds for OT, and vasopressin receptor subtypes were investigated. In vitro effects of antagonists were evaluated via inhibition of OT-induced contractions of isolated guinea-pig uterus. The abilities of OT antagonists to inhibit spontaneous contractility in 24 h postpartum rat uterus were investigated. These peptides exhibited pseudoirreversible pharmacological properties, and comprise a novel group of OT antagonists for potential clinical use. Their noncompetitive pharmacological nature can be of therapeutic benefit through a sustained effect on myometrium.

[Pharmacological models to investigate the role of the adrenergic system on post-partum rat uterus]

The adrenergic system plays a major role in the regulation of the pregnant uterine contractility. Our aim was to develop an experimental animal model to study the role of the alpha 1A-adrenergic receptor (AR) in uterine motor activity by antisense oligonucleotides (AONs). AONs were injected with DOTAP and pluronic gel into the uterine lumen of post-partum rats 2-3 hours after delivery. The decrease of the alpha 1A-AR density by AON was demonstrated by RT-PCR method, Western blot analysis and radioligand binding assay on rat uterus preparations 24 h after delivery. The changes in the contractility of the uterus were measured on isolated rat uterine tissue by electric field stimulation (EFS). The EFS investigation demonstrated that the effect of the specific alpha 1A-blocker 5-methylurapidil and WB4101 was significantly decreased in the AON-treated rat uterus as compared to the control group but the effect of the beta-mimetic terbutalin and alpha 1D-antagonist BMY7378 was unchanged. Our result suggest that the alpha 1A-ARs play a very important role in the regulation of uterine contractility, and may serve as the basis for a subsequent new group of tocolytics (uterus selective alpha 1-antagonists), which may lead to more selective therapy than currently used beta-mimetics.

[Influence of adrenergic denervation on uterine contractility of pregnant rats in vitro]

The aim of the present study was to investigate the functional changes in the sympathetic nerves in the rat myometrium during pregnancy by electric field stimulation (EFS) in vitro. In our experiments the contractility of the rat myometrium were registered at 5, 10, 15, 18, 20, 22 (term) day of pregnancy, in non pregnant rats and in 6-OH-dopamine pretreated rats. The parameters of EFS were the following: pulse width 0.6 ms, frequency range of nerve stimulation 1-70 Hz, supramaximal voltage 40 V. We concluded that low pulse width and low frequency stimulation is selective for adrenergic nerves. We found that during pregnancy a gradual drop-out of low frequency induced uterine smooth muscle contraction appears. It is surprising that very low frequency stimulation has no effect on the 5th day of pregnancy although the same frequency stimulation causes contraction on the 10th day. By the 22nd day of pregnancy the rat uterus shows the same responsiveness to nerve stimulation as it is detected in 6-OH-dopamine pretreated non pregnant rats. The adrenergic denervation of the pregnant uterus does not mean that it loses the ability to respond to cathecholamines since non-synaptic adrenergic receptors exist in the late pregnant rat uterus.

Antioxidant activity of leaves of Salvia species in enzyme-dependent and enzyme-independent systems of lipid peroxidation and their phenolic constituents

The protective effects of eleven Salvia species native to Europe against enzyme-dependent and enzyme-independent lipid peroxidation were evaluated. The 50% aqueous methanolic extracts of the leaves of all tested plants were found to be more effective than the positive control alpha-tocopherol acid succinate. The extracts of S. candelabrum, S. ringens, S. tomentosa, S. nemorosa, and S. glutinosa displayed considerable concentration-dependent antioxidative effects that were comparable to those of the medicinal and aromatic plant S. officinalis. The concentrations of flavonoids, hydroxycinnamic acids and total phenolic compounds in each extract were quantified with the aim of clarifying the connection between activity and chemical composition.

Use of antisense oligonucleotides to verify the role of the alpha(1A)-adrenergic receptor in the contractility of the rat uterus post partum

The adrenergic system plays a major role in the regulation of the contractility of the uterus during pregnancy. This study investigated the role of the alpha(1A)-adrenergic receptor (AR) in this regulation. The use of partial phosphorothioate antisense oligodeoxynucleotides (AONs) permitted the sequence-selective inhibition of AR gene expression. AONs were injected together with a cationic liposomal carrier agent into the post partum rat uterus. Incubation for 12 or 24 h with the most effective AON (480-AON) caused a 58.7 or 53.0% inhibition, respectively, of the expression of the alpha(1A)-AR density, whereas incubation for 36 or 48 h resulted in only a 38.8 or 26.7% inhibition, respectively. The decrease of the alpha(1A)-AR density by 480-AON was demonstrated by Western blot analysis and a radioreceptor binding assay on rat uterus preparations 24 h after delivery. The changes in the contractility of the uterus after AON treatment were measured on isolated rat uterine tissue by electric field stimulation. The significant decrease in the ability of the uterus to contract was indicated by the area under the curve method. The electric field studies revealed that the specific alpha(1A)-blockers 5-methylurapidil and WB 4101 inhibited the rhythmic contraction by about 74 and 70% in the control uteri and by 25 and 20% in 480-AON-treated uteri, respectively. The curves for the beta-mimetic (terbutaline) and alpha(1D)-antagonist (BMY7370) inhibitors were unchanged after 480-AON treatment of the uteri. These results suggest the importance of the alpha(1A)-AR in the tocolytic effect exerted by the alpha(1)-antagonist, although high concentrations of antagonists can not exclude the role of alpha(1D)-ARs, too. Additionally, these prove that the knockdown transformation by AONs offers a useful animal model for the investigation of receptors controlling the function of uterine tissue.

Study of in vitro and in vivo dissolution of theophylline from film-coated pellets

Tests were performed on the influence of polymer coating films on the rates and the extents of in vitro and in vivo liberation of theophylline from pellets. Uncoated and coated pellets were used in the experiments. The coating material was Eudragit L; The film thickness was varied. The in vivo liberation of theophylline was studied in rabbits. The serum level of the released drug measured with a TDX Analyser. No appreciable difference was observed between the uncoated and the coated pellets as concern the maximum release data, but a significant shift was found in t(max) for Eudragit L coated pellets.

Characterization of late-pregnant rat uterine contraction via the contractility ratio in vitro significance of alpha1-adrenoceptors

The aim of this study was to characterize the ability of late-pregnant (days 15-22) rat uterine tissue rings to contract in response to electric field stimulation in vitro. For this purpose, maximum rhythmic contractions were elicited by optimum choice of the period time and the pulse width, the two main parameters of electric field stimulation. In parallel, the plasma 17beta-estradiol and progesterone levels were determined. It was found that the contractility ratio, i.e. the quotient of the optimum pulse width and the period time, is a good parameter with which to express the contractility. The larger the contractility ratio, the better the ability to contract. Evaluation of the area under the curve did not furnish information relating to the contractility in this method. A very close correlation was observed between the contractility ratio and the quotient of the 17beta-estradiol and progesterone levels on different days, demonstrating that the in vitro ability characterized by the contractility ratio is in keeping with the physiological regularity. There was also a very close correlation between the contractility ratio and the quotient of the alpha1- and beta-adrenergic receptors, suggesting the main role of the numbers of alpha1-receptor in pregnant uterine contractility. It is believed that this is the first in vitro model to give a numerical measure concerning the ontogeny of uterine contractility in late pregnancy.

On a possible new intracellular signal-system in rat gastric mucosa

It is known that cAMP and cGMP, as an "intracellular second messenger system" play a significant role as a signal system, in the mechanism of action of anti-ulcerogenic (cytoprotective) drugs. According to our present, preliminary investigations it seems that during different experimental circumstances the gastric mucosal 3'-5'-cyclic-cytidine-mono-phosphate (cCMP) 3'-5'-cyclic-uridine-monophosphate and (cUMP) levels were changed--similarly to CAMP and cGMP--and these changes might be a possible indicator of a further, most probably secondary, signal- system role.

[Synthesis and in vitro receptor analysis of new potential oxytocin antagonists]

Oxytocin (OT) itself and the sensitivity of the uterus to OT play a crucial role in the initiation of both normal and pathologically early delivery. It recognition of the complex mechanism of action suggests that specific OT antagonists are of therapeutic value in postponing early contractions. In this study neurohypophyseal hormone analogues containing Sar in position 7, Arg in position 8, and various conformationally restricted or bulky derivatives of phenilalanine and tryptophan amino acids in position 2 were prepared to design more potent and selective OT antagonists. We determined the ligand-receptor binding characteristics of these newly synthetized peptides in the presence of [3H]oxytocin and [3H]vasopressin on isolated guinea-pig uterus, rat liver and kidney inner medulla plasma membranes. In the case of each peptides we calculated the Ki values and the selectivity ratio. The binding to the OT receptor was dramatically decreased for the Trp-derivatives containing analogues, while the Phe-derivatives containing analogues displayed a relatively high receptor affinity and have a relatively high OT/VP1 receptor selectivity.

Synthesis and biological activity of a new progestogen, 16-methylene-17alpha-hydroxy-18-methyl-19-norpregn-4-ene-3, 20-dione acetate

The progestational activity of second- and third-generation progestins in oral contraceptives were markedly increased by addition of an 18-methyl group. A new progestin, the 18-methyl analog of Nestorone, 16-methylene-17alpha-hydroxy-18-methyl-19-norpregn-4-ene-3,2 0-dione acetate (10), was synthesized. The relative binding affinity and biologic activity of 10 was compared with Nestorone, levonorgestrel, and progesterone using a binding assay for rat progesterone receptors, the Clauberg assay in the rabbit, and by assessing pregnancy maintenance in the rat. These studies, as summarized in Table 4, show that 10 is three to ten times more potent than Nestorone. The addition of the 18-methyl group to Nestorone markedly increased its potency as noted above, but is unlikely to change its rate of delivery from sustained release systems. 10 should be ideally suited for administration by implants or small skin patches.

Protective effects of the aerial parts of Salvia officinalis, Melissa Officinalis and Lavandula angustifolia and their constituents against enzyme-dependent and enzyme-independent lipid peroxidation

The antioxidant effects of aqueous methanolic extracts from three medicinal Lamiaceae species were investigated in enzyme-dependent and enzyme-independent lipid peroxidation systems. All these extracts caused a considerable concentration-dependent inhibition of lipid peroxidation. Phenolic components present in the plant extracts were evaluated for antioxidant activity and were found effective in both tests. Their concentrations in each extract were determined by TLC-densitometry.

Jatrophane diterpenoids from Euphorbia peplus

From the pro-inflammatory active extract of Euphorbia peplus, a new diterpene polyester (1) based on the jatrophane skeleton was isolated together with the known compounds 2-5. The irritant activities of some jatrophane diterpenes (2, 3 and 6-9) were also investigated: only compound 2 was found to exert a weak pro-inflammatory activity on mouse ear.

Ontogeny of imidazoline binding sites in the human placenta

INTRODUCTION

Non-adrenergic imidazoline binding sites (IBS) were described as pharmacologically distinct from alpha2-adrenergic receptors. Recently it was shown that the human placenta is the richest source of IBS, however, no function has been assigned to this new putative receptor. As concerns the presence of alpha2-adrenoceptors in the human placenta, it was reported that no alpha2-receptors were detected in human placental membranes with the radiolabelled alpha2-adrenoceptor antagonist [3H]rauwolscine or the alpha2-adrenoceptor agonist [3H]clonidine. This scientific contradiction has been solved when the authors have recently demonstrated that IBS and alpha2-adrenoceptors coexist in human term placental membranes.

STUDY OBJECTIVE

Scientific literature does not provide any information regarding the ontogeny of IBS. The present study intended to determine the density of IBS and alpha2-adrenoceptors in correlation with gestational age.

MATERIALS AND METHODS

Human first and second trimester placentas (6-10 and 14-18 weeks of gestation, respectively) were obtained immediately following the interruption of gestation, third trimester placentas (38-40 weeks) were obtained after normal vaginal delivery. Human placental membrane fractions were prepared and radioligand binding assays were performed in duplicate, using [3H]RX 821002 and [3H]RX 781094 (idazoxan) as radioligands.

RESULTS

According to the results of the binding assays, the concentration of alpha2-adrenoceptors decreased with the advancing gestational age. In contrast with this pattern, the density of IBS significantly increased.

CONCLUSION

Our present results demonstrated that the density of IBS shows a significantly increasing tendency throughout gestation. The unique position of the placenta between maternal and fetal circulations determines its function as a mediator in transport mechanisms. The increasing expression of IBS in the growing placenta might suggest a role for these sites in the mediation of the transport of nutrients, ions, etc.

In vivo effects of 2-substituted [Mpa1Sar7Arg8]-oxytocin antagonists on postpartum rat

A set of oxytocin antagonists consisting of [Mpa1Sar7Arg8]-oxytocin substituted by various conformationally restricted or bulky D amino acids at position 2 were synthetized and biologically tested. In in vivo pharmacological investigations, the effects of these peptides were examined on the spontaneous motor activity of postpartum rat. Three of the newly prepared peptides proved at least as effective in inhibiting uterine contractions as clinically investigated atosiban.

Correlation between alpha1/beta-adrenoceptor ratio and spontaneous uterine motor activity in the post-partum rat

The spontaneous uterine motor activity of the post-partum rat was investigated in parallel with the in-vitro determination of the density of the alpha1 and beta-adrenergic receptors of the myometrium. The in-vivo experiments were performed by an improved method, using a Millar catheter fitted with a latex microballoon. The spontaneous contractility of the post-partum rat uterus was found to be highest 24 h after delivery, indicating that this time is the most suitable for pharmacological examinations of tocolytic agents. A very close correlation was found between the results of the in-vivo experiments and the alpha1/beta-adrenergic receptor ratio assessed by an in-vitro receptor assay, thus indicating that the state of the adrenergic receptor system fundamentally determines the contractility of the uterus. This conclusion is supported by the fact that the pharmacological sensitivity of the rat uterus to prazosin and fenoterol changed as a function of the post-partum time in accordance with the alpha1/beta-adrenoceptor ratio. These results and the relevant data available reveal a crucially important role of an alpha1-adrenoceptor-mediated process, implicating alpha1-blockers as theoretically potent agents for inhibition of premature uterine contractions.

Computer analysis of video and ultrasonographic images for evaluation of bull testes

The objectives of this study were to determine relationships between scrotal size (SC; estimated from a video image) and testicular size, and between ultrasonographic echotexture of the testis and seminiferous tubule area in bulls. Video images of the scrotum of 49 Holstein-Friesian (H-F) bulls were recorded and digitized. Scrotal width and length were measured with custom software. After slaughter, scrotums (containing testes) were excised, SC and testicular height, width and volume were measured, and the testes were examined ultrasonographically. Correlations between SC and testicular width or volume (r = 0.86, P < 0.001 and r = 0.84, P < 0.001, respectively) were much higher than those between scrotal width and testicular width or volume (r = 0.23, P < 0.11 and r = 0.28, P < 0.06). Histological examination of the testes was performed in 31 of the bulls. Ultrasonographic echotexture of the testes (determined with custom software) was highly correlated (r = -0.5, P < 0.005) with seminiferous tubule area. Although SC was superior to video imaging for estimating testicular size, ultrasonographic imaging of the testes has considerable potential for the evaluation of testicular function in bulls.

Endocrine and thermal responses to GnRH treatment and prediction of sperm output and viability in holstein-Friesian breeding bulls

A study was conducted to determine changes in serum LH and testosterone concentrations and in scrotal surface temperature (SST; measured with infrared thermography) following GnRH treatment and to predict the number of spermatozoa collected and the proportion that were viable. Holstein-Friesian breeding bulls (n = 22, average age, 24.3 m.o.; range, 15 to 41 m.o.) were examined twice 30 d apart. Concurrently, semen was collected twice weekly with an artificial vagina. Treatment with GnRH (100 micrograms, i.m.) increased (P < 0.0001) serum LH and testosterone concentrations and increased (P < 0.0001) SST (range 0.6 to 1.1 degrees C; P < 0.05) at the top and bottom of the scrotum. In regression models to predict the total number of spermatozoa, significant independent variables included ultrasonic echotexture of the testes (negative slope), scrotal width (positive slope) and SST at the bottom of the scrotum 45 min after GnRH treatment (positive slope). In regression models to predict the percentage of live spermatozoa, ultrasonic echotexture was a significant independent variable (negative slope). Measurement of testicular ultrasonic echotexture and SST after GnRH treatment augmented measurement of testicular size for predicting the number and percentage of live spermatozoa.

Morphologic, endocrine and thermographic measurements of testicles in comparison with semen characteristics in mature Holstein-Friesian breeding bulls

Twenty Holstein-Friesian breeding bulls (62-79 months of age) were examined 3 times, at 30-day intervals. Scrotal thermograms for assessment of scrotal surface temperature (SST) and blood samples for plasma testosterone concentrations were taken just before and then 45 and 90 min, respectively, after treatment with GnRH (50 micrograms, Gonavet, i.m. per bull). Following GnRH treatment, there generally were significant increases in mean values of both top SST (range, -0.1 to 1.4 degrees C) and bottom SST (range, 0.3 to 1.8 degrees C). Scrotal circumference was highly repeatable but SST and video-measurements of scrotal dimensions were less repeatable, because apparently they were affected by ambient temperature. Plasma testosterone concentrations before GnRH treatment were more repeatable than those after GnRH treatment. Correlations between examinations of 0.67 to 0.81 and -0.14 to 0.47, respectively, but the converse was true for SST measurements. Semen was collected with an artificial vagina 3 times per week for 12 weeks starting 2 weeks before the first examination. The total number of spermatozoa per ejaculate was highly repeatable and the percentage of motile and live spermatozoa were relatively consistent. Separate regressions for each variable and for each examination were conducted for these 3 semen characteristics as dependent variables. For the number of spermatozoa per ejaculate and for the percentage of motile spermatozoa, significant independent variables were plasma testosterone concentrations and difference between top and bottom SST, respectively. The slopes of these equations were nearly all negative and the R2 was from 0.15 to 0.42. For prediction of the percentage of live spermatozoa, both SST gradient and plasma testosterone concentrations were significant independent variables. For these regressions, the slopes were negative and the regression coefficients were generally lower than for the other 2 dependent variables (range, 0.16 to 0.25). Treatment with GnRH and assessment of SST and plasma testosterone concentrations have some correlation with the semen production in the mature bull.

Do alpha 2-adrenoceptors and imidazoline binding sites coexist in the human term placenta? Evidence from direct binding studies

Alpha2-Adrenergic receptors and non-adrenergic imidazoline binding sites (IBS) in human placental membranes were investigated by means of the radioligands [3H]-RX 821002 and [3H]-RX 781094 (idazoxan) respectively. Human term placentae (38-40 weeks) were obtained immediately after vaginal delivery. The specific binding of the alpha2-subtype-selective [3H]-RX 821002 confirms the presence of alpha2-adrenoceptors in the human placenta, while [3H]-idazoxan binds to non-adrenergic IBS. The sites were characterized by displacement analyses with various imidazoline and non-imidazoline drugs. The presence of an endogenous ligand for IBS has not yet been demonstrated. Clonidine displacing substance (CDS) was recently identified as agmatine; it recognizes both alpha2 and imidazoline receptors. This phenomenon was studied in crude placental membranes. The studies revealed that: (i) alpha2-adrenoceptors coexist with non-adrenergic IBS in human placental membranes; (ii) there is a strong probability that alpha2-adrenoceptors and IBS are pharmacologically distinct; and (iii) agmatine binds to placental alpha2 and imidazoline receptors with different affinities.

Evidence of non-synaptic regulation of postpartum uterine contractility in the rat

Myometrial tissue rings from postpartum rats (24 h after delivery) were studied in vitro by electric field stimulation, and the alpha1/beta2-adrenoceptor ratio was determined by a radioligand binding technique. Pregnancy-denervated uterine rings were stimulated by long-duration pulses (100 ms). The contractions were inhibited by beta2-agonists (terbutaline and fenoterol) and alpha-antagonists (phentolamine, urapidil and yohimbine) in a concentration-dependent manner. Their effects were not altered by the adrenergic neuron-blocking agent bretylium. The alpha-antagonists (except phentolamine) elicited the same maximal inhibition as the beta2-agonists. Receptor assays revealed that the alpha1/beta2 ratio was about 2 in the measured uteri. It was concluded that the inhibitory effects of alpha-antagonists and beta2-agonists are mediated via non-synaptic adrenoceptors of the denervated postpartum rat uterus. The same inhibitory activity could be explained by the greater amount of alpha-receptors. It is believed that this is the first functional proof of the existence of non-synaptic alpha1-adrenoceptors in smooth muscle.

Are alpha-adrenergic antagonists potent tocolytics? In vivo experiments on postpartum rats

The aim of this study was to investigate the effects of alpha-adrenergic antagonists on the motor activity of the postpartum uterus of the rat in vivo. Intrauterine pressure was assessed by means of a Millar catheter fitted with a latex microballoon. Some of the tested compounds (urapidil, yohimbine, phentolamine, benoxathian and prazosin) decreased the uterine activity to a significant extent (57.4-67.4%). However, none of the investigated alpha receptor blockers exerted the same effect as beta-adrenergic agonists. Our results suggest that alpha-adrenergic antagonists could possibly be used as an alternative to beta-adrenergic agonists in clinical tocolysis after an appropriate clinical evaluation.

Determination of RU486 (mifepristone) in blood by radioreceptorassay; a pharmacokinetic study

A human progesterone receptor assay has been developed for the measurement of the biologically active molecular fraction of RU486 (RU486 binding equivalent) for studying its pharmacokinetic properties. Thirty-nine healthy pregnant volunteers with amenorrhoea of 49 days or less receiving a single oral dose of 200 mg, 400 mg or 600 mg RU486 orally in a single dose were involved in this study. Blood samples were collected within 48 hours for the analysis. It was found that the pharmacokinetics of the RU486 binding equivalent followed an open two-compartment model. The dose was rapidly absorbed and peak serum concentrations were measured within 1-2 hours after ingestion of the drug. The distribution was also rapid, but the elimination was slow, the elimination half-life ranging between 83 and 90 hours. Significant differences were found between the peak plasma values for the 200 mg and 600 mg doses (p < 0.05) and between the AUCs for the 200 mg and 600 mg doses (p < 0.01) and the 400 mg and 600 mg doses (p < 0.05). It can be concluded that this newly developed radioreceptor assay satisfies the requirements of radioligand binding techniques and can be used to determine the serum levels of RU486 and its metabolites, which are able to bind to human myometrial progesterone receptors. The pharmacokinetics for the RU486 binding equivalent is similar to that for RU486, with the exception of very slow elimination, which may originate from the measurement of the biologically active metabolites together with the parent compound.

Expression of two alpha 2-adrenergic receptor subtypes in human placenta: evidence from direct binding studies

Adrenergic receptors may play an important role for mediating a variety of metabolic and haemodynamic effects of catecholamines including placental blood flow. The alpha-adrenergic receptors of the human placenta were characterized in vitro by the use of [3H]rauwolscine and [3H]prazosin as radioligands. Saturation experiments would suggest that the alpha-adrenoceptors in the human placenta are alpha 2. Comparative binding studies were performed, using recently synthesized compounds (Beecham Pharmaceuticals, UK) selective for alpha 2A (BRL-44408) and alpha 2B (BRL-41992) subtypes. The results indicate that human placenta contains at least two pharmacologically distinct alpha 2-adrenoceptor subtypes with approximately 60 per cent alpha 2A and 40 per cent alpha 2B receptors. In contrast with the pattern of increasing beta-adrenoceptor density, the concentration of alpha 2-adrenoceptors in term placentae is significantly lower than in placentae from the first trimester.

Correlation between beta- and alpha-adrenergic receptor concentrations in human placenta

alpha 2- and beta-adrenergic receptors in human placental membranes have been investigated using the radioligands [3H]-RX 821002 and [3H]-dihydroalprenolol, respectively. The specific binding of the alpha 2-adrenoceptor antagonist RX 821002 confirms the presence of an alpha 2-adrenoceptor in the human placenta, which has been characterized previously with [3H]-rauwolscine. The major finding presented here is a correlation between the alpha 2- and beta-adrenergic receptor concentrations (r = 0.765) in the human placenta at term. It is suggested that the alpha 2/beta adrenoceptor balance may play an important role in regulation of the vascular bed of the placenta. Determination of the alpha 2/beta ratio may help towards an understanding of the contractility of the placental vascular muscles.

[Pharmacokinetics of RU 486 and its active metabolites in humans]

The pharmacokinetics of RU 486 and its active metabolites were studied in 31 women who received a single oral dose of 200 mg (n = 9), 400 mg (n = 10) or 600 mg (n = 12) of RU 486 for termination of an early unwanted pregnancy. The serum levels were measured within 48 hours after the intake by radioligand binding assay using human myometrial cytosolic progesterone receptor as binding protein. The assay is based on the competitive replacement of 3H-ORG-2058 by the active molecular fraction of RU 486 present in the serum. The results were expressed as RU 486 equivalent. It was found that pharmacokinetics of the RU 486 equivalent followed two-compartment open model. The pharmacokinetic parameters were calculated by MEDUSA computer programme. Rapid absorption and distribution was followed by relatively slow elimination. The elimination half-life ranged between 80-90 hours. No significant difference was found between the parameters of the absorption distribution and elimination processes of three different doses. Thus, the RU 486 equivalent followed first-order kinetic. Peak serum concentrations were reached within 1-2 hours after the ingestion of the drug. Significant differences were found between 200 and 600 mg doses in the peak plasma values (p < 0.05) and in the areas under the curve (p < 0.01). However, these differences were not directly proportional to the increase of the dose.

Changes in adrenergic receptors in the pregnant human uterine cervix following mifepristone or placebo treatment in the first trimester

There is increasing evidence that the antiprogesterone mifepristone (RU-486) can dilate the cervix of pregnant women. The uterine and cervical smooth muscle contractile response to adrenergic agonists is regulated by the steroidal environment. This study was undertaken to assess the effects of treatment with RU-486 on the concentrations of alpha- and beta-adrenoceptors in cervical crude membranes from pregnant women using a radioligand binding assay. A special needle biopsy technique was used for human cervical specimens. The probable relative oestrogen dominance due to the antiprogesterone treatment selectively decreased the alpha-2 adrenoceptor in human cervix at an early stage of gestation. This finding was similar to that reported earlier in pregnant rabbits. The existence of a functionally distinct alpha-2 adrenergic receptor subtype will have important implications for our understanding of the contractile activity of the cervix.

[Radioreceptor assay for determination of the anti-progestogen, RU-486 and its active metabolites in the blood]

RU-486 is an antiprogesterone 19-norsteroid with high binding affinity for the progesterone receptor. It can be used with success for termination of early human pregnancy. Since the metabolites of RU-486 are often biologically active, their concentrations in blood can also have clinical significance. We have developed a rapid sensitive radio receptor assay for determination of RU-486 and its active metabolites. Human myometrium progesterone receptor was used as binding protein. The assay is based on the competitive replacement of 3H-ORG-2058 by the active molecular fraction of RU-486 present in the serum. The analytical parameters of this assay are the followings: intraassay percent of coefficient of variation (CV%) is ranged between 7.6 and 10.4%. The interassay CV% was from 7.1 to 16.3. The sensitivity of the receptor assay was 8.7 pmol/tube and the acceptable range was between 10 and 120 pmol/tube. The recovery ranged between 95 and 122% (r = 0.983). These parameters are suitable for the requirement of radioligand binding techniques based on the immunoassays.

Lysosomal enzyme activities in frozen, non-cultured chorionic villi for prenatal diagnosis of enzymopathies

Normal reference values of lysosomal enzyme activities (alpha-glucosidase, mannosidase, fucosidase and arylsulfatase-A) were determined in chorionic villi obtained from artificial abortion in the first trimester of normal pregnancies (gestational weeks 6 to 11). Villi were homogenized comparatively either in saline or in Triton X-100 detergent. The alpha-glucosidase, mannosidase and arylsulfatase-A enzyme activities significantly diminished if homogenization was done in saline instead of Triton-X while the difference in fucosidase activity was not significant. Significant correlation was detected between alpha-glucosidase activity and week of gestation. It is suggested that Triton X-100-homogenization should be used for the lysosomal enzyme determinations in chorionic villi because the solubilization of enzymes from the lysosomes is complete in this case than with homogenization in saline.

Effects of antiprogestogen (RU-486) treatment on myometrial and cervical alpha and beta-adrenoceptors in pregnant rabbits

Oestrogen and progesterone influence myometrial and cervical responses at different levels of the mechanisms regulating uterine contractility. One of these mechanisms could involve alterations in the adrenoceptor concentrations. This study was undertaken to assess the effects of treatment with the antiprogestogen RU-486 on the concentrations of alpha- and beta-adrenoceptors in pregnant rabbit myometrial and cervical membranes by means of a radioligand binding technique. The probable relative oestrogen dominance due to the antiprogestogen treatment selectively decreased the alpha 2-adrenoceptor subtype in the cervix, where an alpha-adrenoceptor dominance was found on day 27 of pregnancy. The results indicate a heterologous regulation of alpha-adrenoceptors by sex steroids, i.e. suppression of the alpha 2-adrenoceptor concentration by antiprogestogen treatment.

[Therapeutic use of a gonadotropin releasing hormone analogue in breast cancer]

Superagonistic analogues of Gn-RH given chronically produce a paradoxic inhibition of pituitary gonadotropin secretion and consequently decrease the peripheric hormones estradiol and progesterone to a postmenopausal level. For curative purposes buserelin (SuprefactR, Hoechst) treatment has been performed by the authors in two cases of breast cancer. The patients--one with NED (no evidence of disease) and the other with pulmonary and osseal metastases--in addition to low hormonal levels developed amenorrhoea. A group of climacteric complaints were observed without any toxic side effects, however. The treatment of premenopausal women suffering from breast cancer with chronic administration of Gn-RH analogues may constitute a valuable alternative to surgical oophorectomy.

Physiological values of cysteine and metalloproteinase activities in chorionic villi

Lysosomal cysteine proteinases (cathepsin H, B + L) and metalloproteinase (MMP7-ase) activities were measured from early gestational period (6-12 weeks) in frozen, non-cultivated chorionic villi. The mean activity of cathepsin H was 50.99 mU/mg protein, of cathepsin B + L, 71.16 mU/mg protein, and of MMP7-ase, 16.16 mU/mg protein. The MMP7-ase enzyme activities showed a correlation with gestational age. There was a significant correlation between the activities of cathepsin H and MMP7-ase.

Adrenergic receptors in human fetal liver membranes

The adrenergic receptor binding capacities in human fetal and adult livers were measured to investigate the mechanism of the reduced alpha-1 adrenoreceptor response of the liver associated with a reciprocal increase in beta-adrenoreceptor activity in a number of conditions. Alpha-1 and beta-adrenoreceptor density were determined using 3H-prazosin and 3H-dihydroalprenolol, respectively, as radioligand. Heterogenous populations of beta-adrenoreceptors were found in fetal liver contrast to adult. Decreased alpha-1 and increased beta-receptor density were found which may relate to a decreased level in cellular differentiation. These findings may be important for the investigation of perinatal hypoglycaemia of newborns after treatment of premature labour with beta-mimetics. This is the first demonstration of differences in the ratio of alpha-1 and beta-adrenoceptors in human fetal liver.

Modulation of uterine GABAA receptors during gestation and by tetrahydroprogesterone

Binding of a GABAA receptor agonist, [3H]muscimol, was studied in rat uterine membranes of non-pregnant rats and those at days 15 and 19 of pregnancy. Also, an interaction of the uterine GABAA receptors with tetrahydroprogesterone was examined. At day 15 of gestation [3H]muscimol binding was twice as high as in non-pregnant rats, but at day 19 it was reduced. These changes resulted from an increase of the receptor affinity and decrease of the receptor density, at days 15 and 19, respectively. Since tetrahydroprogesterone, in vitro, also increased [3H]muscimol binding, we propose that this steroid may participate in regulation of uterine function during pregnancy.

No evidence of the existence of beta adrenoceptors in human sperm using radioligand binding technique

The investigations were carried out on 20 freshly ejaculated and pooled samples of human semen with normozoospermia and motility of 70-80%. In the present study no difference was found between total and non-specific binding to semen membranes using [3H]-dihydroalprenolol (DHA) as a radioligand. Our results suggest that beta adrenoceptors could not be found in human sperm.

Pregnancy-induced alterations of GABAA receptor sensitivity in maternal brain: an antecedent of post-partum 'blues'?

Pregnancy increases affinity of [3H]muscimol binding to GABAA receptors in the rat forebrain. Post-partum, the receptor affinity is further increased concomitantly with a reduction of the receptor density. These changes may result from an action of endogenous placental and adrenal steroids, tetrahydroprogesterone and tetrahydrodeoxycorticosterone, which in vitro behave as allosteric agonists of GABAA receptors. The alterations may contribute to the psychological phenomena associated with pregnancy and the puerperium.