Effect of estrogen on muscarinic acetylcholine receptor expression in rat myometrium.

We report the effect of acute estrogen treatment in the expression of muscarinic acetylcholine receptors (mAChRs) in myometrium. Strips were obtained from rats in estrus (control) and treated with estrogen, 24h before the experiments. Reverse transcriptase-polymerase chain reaction (RT-PCR) was performed and m2, m3 and m5 mAChR mRNA subtypes were detected in myometrium from both groups.

Angiotensin receptor in the heart of Bothrops jararaca snake.

Angiotensin II interacts with specific cell surface angiotensin AT1 and AT2 receptors and, in some vertebrates, with an atypical angiotensin AT receptor. This study was designed to characterize the angiotensin receptor in the heart of Bothrops jararaca snake. A specific and saturable angiotensin II binding site was detected in cardiac membranes and yielded Kd=7.

Receptor-mediated endocytosis of angiotensin II in rat myometrial cells.

The events involved in the processing of the angiotensin II (Ang II)-receptor complex were studied in primary cultures of rat myometrial cells. Ang II bound to rat myometrial cells in a specific, time- and temperature-dependent fashion. Pretreatment with cycloheximide did not interfere with binding up to 3 hr, but inhibited increases in binding observed over longer periods.

Two kinds of tryptamine receptor. 1957.

There are two kinds of tryptamine receptor in the guinea-pig ileum, namely the M receptors which can be blocked with morphine and the D receptors which can be blocked with dibenzyline. Atropine, an atropine-like drug, cocaine, and methadone inhibit effects due to the M receptors, even after dibenzyline, but have no additional effect after morphine. Lysergic acid diethylamide, dihydroergotamine and 5-benzyloxygramine inhibit effects due to the D receptors, even after morphine, but have no additional effect after dibenzyline.

Isolation and identification of angiotensin-like peptides from the plasma of the snake Bothrops jararaca.

Two distinct hypertensive peptides were purified and characterized from Bothrops jararaca (Bj) plasma incubated at pH 4, 37 degrees C, 24 hr. These peptides were active on rat and Bj blood pressure, on rat isolated uterus, on guinea pig isolated ileum and on Bj isolated duodenum. At the releasing conditions no further activities were found for kininases, angiotensinases or angiotensin converting enzymes.

Experimental cryptorchidism in prepubertal rats: some effects on reactivity of the seminal vesicle to catecholamines.

The development of testes and genital accessory organs, the plasma testosterone concentration and the reactivity of seminal vesicles to catecholamines were studied in rats rendered cryptorchid at the time of prepubertal growth. The wet weights of the accessory organs and the testosterone concentrations were reduced and corresponded to those observed after castration. The response of the seminal vesicle to adrenaline and noradrenaline, but not to methoxamine, showed a reduction in sensitivity.

Circulating vasotocin in the snake Bothrops jararaca.

1. There is biochemical and pharmacological evidence to suggest the presence of vasotocin in the blood and plasma of the snake Bothrops jararaca (Bj). 2.

Effect of chymotrypsin on rat blood pressure.

1. Chymotrypsin (Cht) administration (14 mg/kg, i.v.

Hydrolysis of L-cystine-di-beta-naphthylamide and neurohypophyseal peptides by the plasma of the snake Bothrops jararaca.

1. Bothrops jararaca plasma or serum hydrolysed L-cystine-di-beta-naphthylamide (CNAse activity) at a degree comparable to that of plasma or serum in pregnant women. 2.

Active and inactive renin in the plasma of the snake Bothrops jararaca.

1. Complementing the work of Gervitz R. K.

The vasopressor action of angiotensin in the snake Bothrops jararaca.

1. Carotid blood pressure from anesthetized B. jararaca snakes was recorded in order to study angiotensin action in this reptile.

Effects of catecholamines on the isolated aorta of the snake Bothrops jararaca.

1. Effects of catecholamines in snakes have been examined using an aorta preparation isolated from Bothrops jararaca. Adrenaline, noradrenaline and isoprenaline produced dose-dependent contractions on this preparation.

Kallikrein-kinin system in the plasma of snakes.

Using pharmacological preparations suitable for assay of mammalian kinins, it was shown that Bothrops jararaca (Bj) venom and other kininogenases were unable to release kinins from snake plasma. The kallikrein-kinin system presents species-specificity in birds. In order to detect such a specificity in snakes, the effects of Bj venom on snake blood pressure and the effect of incubates of snake plasma with trypsin, on snake blood pressure and snake uterus, were studied.

Effect of the neonatal steroid hormone treatment of rats on adult hormone levels and the reactivity of seminal vesicles to parasympathomimetic drugs.

1. Seminal vesicle reactivity to cholinergic agents, plasma testosterone, luteinizing hormone (LH) and follicle stimulating hormone (FSH) concentrations and seminal vesicle testosterone concentrations were determined in adult male rats treated during the first 6 h of life with 1.0 ml peanut oil (oil-treated), 1.

Kallikrein-kinin system in the plasma of the snake Bothrops jararaca.

1. Bothrops jararaca venom (BJV) caused a fall in the carotid artery blood pressure of the anaesthetized snake. This effect was tachyphylactic and was potentiated by captopril, a kininase II inhibitor; it was partially antagonized by promethazine plus cimetidine and was not affected by atropine.

Influence of castration and of the kind of sympathomimetic drug used upon the reactivity of rat seminal vesicles.

An interdependence of the hormonal state of rodents and the genital muscle response to drugs was observed either on females or on males. Castration or castration followed by oestradiol treatment increased the responses of rat seminal vesicles to parasympathomimetic drugs. As, however, the influence of such procedures upon the responses to sympathomimetic drugs is controversial, the parameters pD2 (apparent affinity constant), alpha (intrinsic activity) and rho (relative responsiveness) of adrenaline, noradrenaline, methoxamine and phenylephrine on the seminal vesicles isolated from normal and castrated rats were determined.

Effects of castration and antiandrogens (RU 23908 and cyproterone acetate) on glandulain activity and on the secretory epithelium of the rat submandibular gland.

1. The influence of hormones on the submandibular gland of rodents has attracted more attention since the observation of the sexual dimorphism of these organs. Androgens enhance both the development and the secretory activity of the gland.

Influence of castration upon trophism and reactivity of rat seminal vesicles.

1. Castration-induced time-dependent changes in trophism and reactivity of rat seminal vesicles were studied by measuring vesicle weight, spontaneous contractility, apparent sensitivity (pD2) to acetylcholine and acetyl-beta-methylcholine and intrinsic reactivity (alpha) to acetyl-beta-methylcholine 5, 10, 15 and 30 days after surgery. 2.

Influence of castration upon the seminal vesicle response to parasympathomimetic drugs.

The influence of castration upon rat seminal vesicle responses to acetylcholine, carbachol and betanechol has been investigated through the determination of the parameters pD2 (the apparent affinity constant), alpha (the intrinsic activity) and rho (the relative responsiveness) of such drugs on vesicles excised from normal and castrated rats. The pD2 and alpha values for carbachol and betanechol and the pD2 value for acetylcholine increased after orchiectomy; the pD2 increase was greater for the first two drugs than for acetylcholine. No significant difference in the values of rho of the acetylcholine receptor system was obtained after castration.

Changes in the adenohypophysis and genital tract of cryptorchid rats: some morphological and pharmacological aspects.

It has been confirmed that cryptorchidism may affect the control mechanism of gonadotrophin secretion. This has been based on morphological aspects of the adenohypophysis of cryptorchid rats which have shown an increase in basophilic and vacuolated basophilic cells, an increase known to be related to the production of gonadotrophin. The morphological alterations observed in the testes, prostates, seminal vesicles and ductus deferentes of these cryptorchid animals, the quiescence and the responses of their seminal vesicles and ductus deferentes to sympathomimetic and parasympathomimetic drugs indicated that these cryptorchid animals may be somewhere between normal and castrated rats, although not equidistant from either.

Contractile capacity of seminal vesicles from rats in different hormonal conditions.

Isometric contractions of seminal vesicles excised from normal, castrated, estradiol-, testosterone- or norandrostenolone - treated castrated rats were recorded in order to compare their contractile capacity. When expressed as grams of tension per strip of muscle, the vesicles of the castrated rats exhibited the smallest contractile capacity. The contractile force of the organs taken from estradiol-treated castrated rats was higher than that shown by the vesicles of castrates but smaller than those taken from normal, testosterone- or norandrostenolone- treated-castrates.

Effect of full agonists following calcium deprivation in rat vas deferens.

The contractile effects of maximum doses of adrenaline, noradrenaline, methacholine, acetylcholine, serotonin and barium chloride were studied following substitution of a medium without calcium for the normal nutrient solution. Except for the last agonist, the effects fall to about 10% within the first 3 min with prompt return to normal value upon reintroduction of regular fluid. This recovery is, however, slower if the previous incubation in Ca-free solution is prolonged.

Hormonal regulation of rat seminal vesicle sensitivity to adrenaline, noradrenaline, acetylcholine and acetyl-beta-methylcholine.

1. The influence of the hormonal condition of rats on the responsiveness of their seminal vesicles to drugs was investigated by determining pD(2) and alpha values for adrenaline, for noradrenaline, for acetylcholine and for acetyl-beta-methylcholine on isolated vesicles of normal, of castrated, and of oestradiol-treated castrated rats.2.