The hypothalamic supraoptic and paraventricular nuclei consist of oxytocin and arginine vasopressin synthesizing neurons that send projections to the neurohypophysis. A growing body of evidence in adult animals and young animals at near term confirmed the structure and function in the vasopressinergic and oxytocinergic network. However, whether those distinctive neural networks are formed before near term is largely unknown. This study determined the special patterns in location and distribution of oxytocin- and vasopressin-neurons in the paraventricular and supraoptic nuclei from preterm to term in the ovine fetuses. The results showed that oxytocin- and vasopressin-neurons were present in both nuclei at the three gestational time periods (preterm, near term, and term). In the paraventricular nuclei, vasopressin-cells concentrated mainly in the core of the middle magnocellular paraventricular nuclei, and oxytocin-cells were scattered surrounding the core. In the supraoptic nuclei, vasopressin-cells mostly located in the ventral part, and oxytocincells in the dorsal part. The data demonstrated that the special distributed patterns of vasopressin- and oxytocin-neuron network have formed in those two nuclei at least from preterm. Intracerebroventricular injection of angiotensin II significantly increased fetal plasma oxytocin and vasopressin levels at preterm, which was associated with an increase of oxytocin- and vasopressin-neuron activity marked with c-fos expression. The data provided new evidence for the structural and functional development of the oxytocin- and vasopressin-network before birth., L. Shi, Y. Fan, Z. Xu., and Obsahuje seznam literatury
The involvement of the mTOR system/enzyme sirtuin 1 (SIRT1) intracellular signaling system in the control of ovarian functions and its role in mediating hormonal action on the ovary has been proposed, but this hypothesis should be supported by a demonstrated influence of hormones on mTOR/SIRT1. Therefore, the aim of our in vitro experiments was to examine the effect of the known hormonal regulators of ovarian functions, such as follicle-stimulating hormone (FSH), oxytocin (OT) and insulin-like growth factor I (IGF-I), on mTOR/SIRT1. The accumulation of SIRT1 in porcine ovarian granulosa cells cultured with and without these hormones (at doses of 1, 10 or 100 ng.ml-1 ) was evaluated using immunocytochemistry. It was observed that the addition of FSH (at 10 ng.ml-1 but not at 1 or 100 ng/ml) and OT (at all tested doses) increased the expression of SIRT1 in ovarian cells. In addition, 100 ng.ml-1 , but not at 1 or 10 ng.ml-1 , of IGF-I decreased SIRT1 accumulation. Our observations are the first demonstration that hormones can directly regulate the ovarian mTOR/SIRT1 system and that this system could mediate the action of hormonal regulators on the ovary.
Galanin (GAL) is suggested to be a neuropeptide involved in pain transmission. In this study we tried to determine, whether the increase of GAL concentration in brain cells affects impulse transmission between the motor centers localized in the vicinity of the third and fourth cerebral ventricles. The experiments were carried out on rats under chloralose anesthesia. The study objectives were realized using the method allowing to record the amplitude of evoked tongue jerks (ETJ) in response to noxious tooth pulp stimulation during the perfusion of the cerebral ventricles with solutions containing tested compounds. Perfusion of the cerebral ventricles with GAL concentration-dependently inhibited the ETJ amplitude. The antinociceptive effect of GAL was blocked by a galanin receptor antagonist, galantide (GLT) and by opioid antagonists: non-selective naloxone (Nal) and μ-selective β-funaltrexamine (β-FNA). In contrast, a δ-opioid receptor antagonist, naltrindole (NTI) or the κ-opioid receptor antagonist, nor-binaltrophimine (nor-BNI) did not inhibit the effect of GAL. The antinociceptive effect of GAL was more pronounced when GAL was perfused in combination with other neuropeptides/neurohormones, such as endomorphin-2 (EM-2), vasopressin (AVP) and oxytocin (OT). The present results demonstrate that in the orofacial area analgesic activity is modulated by GAL, OT and AVP and that EM-2-induced antinociception involves GAL., M. Zubrzycka, A. Janecka., and Obsahuje bibliografii a bibliografické odkazy
Bone metabolism is regulated by interaction between two skeletal cells – osteoclasts and osteoblasts. Function of these cells is controlled by a number of humoral factors, including neurohormones, which ensure equilibrium between bone resorption and bone formation. Influence of neurohormones on bone metabolism is often bimodal and depends on the tissue, in which the hormone is expressed. While hypothalamic beta-1 and beta-2-adrenergic systems stimulate bone formation, beta-2 receptors in bone tissue activate osteoclatogenesis and increases bone resorption. Chronic stimulation of peripheral beta-2 receptors is known to quicken bone loss and alter the mechanical quality of the skeleton. This is supported by the observation of a low incidence of hip fractures in patients treated with betablockers. A bimodal osteo-tropic effect has also been observed with serotonin. While serotonin synthetized in brain has osteo-anabolic effects, serotonin released from the duodenum inhibits osteoblast activity and decreases bone formation. On the other hand, both cannabinoid systems (CB1 receptors in the brain and CB2 in bone tissue) are unambiguously osteoprotective, especially with regard to the aging skeleton. Positive (protective) effects on bone have also been shown by some hypophyseal hormones, such as thyrotropin (which inhibits bone resorption) and adrenocorticotropic hormone and oxytocin, both of which stimulate bone formation. Low oxytocin levels have been shown to potentiate bone loss induced by hypoestrinism in postmenopausal women, as well as in girls with mental anorexia. In addition to reviewing neurohormones with anabolic effects, this article also reviews neurohormones with unambiguously catabolic effects on the skeleton, such as neuropeptide Y and neuromedin U. An important aim of research in this field is the synthesis of new molecules that can stimulate osteo-anabolic or inhibiting osteo-catabolic processes., I. Žofková, P. Matucha., and Obsahuje bibliografii
The aim of our study was to examine the direct influence of plant polyphenol resveratrol and oil-related environmental contaminant benzene on ovarian hormone release, as well as the ability of resveratrol to prevent the effect of benzene. Porcine ovarian granulosa cells were cultured with and without resveratrol (0, 1,10 or 100 ug/ml) alone or in combination with 0.1% benzene. The release of progesterone, oxytocin and prostaglandin F was measured by enzyme immunoassay (EIA). Benzene promoted the release of progesterone, oxytocin and prostaglandin F. Resveratrol, when given alone, stimulated both progesterone and prostaglandin F, but not the oxytocin output. Moreover, resveratrol prevented and even inverted the stimulatory action of benzene on all analysed hormones. These observations demonstrate the direct influence of both benzene and resveratrol on porcine ovarian hormone release, as well as the ability of resveratrol to prevent the benzene action on the ovary.