820 research outputs found
Allopregnanolone: state of the art.
No full textAllopregnanolone, a neuroactive steroid derived from progesterone, is synthesized within the nervous tissue, by means of specific enzymes. Contrary to progesterone and its first metabolite dihydroprogesterone, allopregnanolone is able to interact with GABA-A receptor and not with the classical progesterone receptor. This suggests that the effect of progesterone administration may be due to activation of progesterone receptor, or of GABA-A receptor, or both. However, this is rarely considered in the experimental studies. Here we summarize and discuss the hot topics involving the actions of allopregnanolone within the nervous tissue. One major role of this neuroactive steroid is neuroprotection in case of lesion, ischemia or peripheral neuropathies (i.e., diabetes). In addition, allopregnanolone may reduce the symptoms of neurodegenerative diseases (e.g., Alzheimer, Parkinson, Niemann-Pick type C, multiple sclerosis) in animal models and now translational studies are developed for its therapeutic use. Allopregnanolone may exert a beneficial effect also in case of neuropathic pain and it is also a potential candidate for the treatment of mood and anxiety disorders. Finally, this neuroactive steroid seems to have important physiological roles in the early differentiation of some neural circuits (in particular at hippocampal level), and to reduce stress during pregnancy. In conclusion, it appears that allopregnanolone is a key regulator of physiological functions and may have interesting therapeutic perspectives for neurodegenerative and psychiatric disorders
Seasonal fluctuations of progesterone receptor in the hypothalamus of the female frog, Rana esculenta
No full textAir Pollution and Mortality for 60 US Cities in 1960
No full textData includes measurements on mortality rate and explanatory variables(air-pollution, socio-economic and meteorological) for 60 US cities in 1960. This data was originally published in McDonald, G.C. and Schwing,R.C. (1973) 'Instabilities of regression estimates relating air pollution to mortality', Technometrics, vol.15, 463-482. It was redistributed through Carnegie Mellon University's StatLib (lib.stat.cmu.edu
The endocrine nervous system : source and target for neuroactive steroids
No full textFor a long time the endocrine brainwas considered to be limited to the hypothalamus and to
its special relationships with the hypophysis. The discovery of the wide distribution of
steroid hormone receptors, as well as that of the possibility of metabolizing or synthesizing
steroids by neural cells (neuroactive steroids), suggests, on the contrary, that interactions
among steroids and nervous system are key points of the regulatory processes in the central
and peripheral nervous system in normal conditions as well as in pathological conditions. In
this brief overview we illustrate a few examples of these relationships with major emphasis
on papers collected in this special issue
Progesterone receptor in the lizard: distribution and properties of progesterone binding sites in the brain
No full textAndrogen receptor deficiency alters the arginine-vasopressin sexually dimorphic system in Tfm rats
No full textIn rodents as well as in many other mammalian and non-mammalian species, the arginine-vasopressin (AVP) system includes a parvocellular sexually dimorphic portion located within the bed nucleus of the stria terminalis (BST), the medial amygdaloid nucleus (MeA) and the lateral septum. In this system, males have more cells and denser projections than females, neurons show androgen and estrogen receptors, and gonadal hormones are required for the activation. However, the role of these hormones for the differentiation of the system is not clear. Previous studies performed on aromatase knockout mice suggested that estradiol is not necessary for the differentiation of the system, but it is important for its activation in adulthood.To elucidate the role of androgens on differentiation and functioning of AVP parvocellular system, we compared male and female rats with a non-functional mutation of androgen receptor (Tfm, testicular feminization mutation) to their control littermates. Our data show that the lack of a functional androgen receptor significantly decreases the expression of AVP immunoreactivity within the BST and MeA of male Tfm. Thus supporting the hypothesis that androgens, through the action of their receptor, should have a relevant role in the organization and modulation of the AVP parvocellular sexually dimorphic system
Effects of xenoestrogens on the differentiation of behaviorally relevant neural circuits.
No full textIt has become increasingly clear that environmental chemicals have the capability of impacting endocrine function. Moreover, these endocrine disrupting chemicals (EDCs) have long term consequences on adult reproductive function, especially if exposure occurs during embryonic development thereby affecting sexual differentiation. Of the EDCs, most of the research has been conducted on the effects of estrogen active compounds. Although androgen active compounds are also present in the environment, much less information is available about their action. However, in the case of xenoestrogens, there is mounting evidence for long-term consequences of early exposure at a range of doses. In this review, we present data relative to two widely used animal models: the mouse and the Japanese quail. These two species long have been used to understand neural, neuroendocrine, and behavioral components of reproduction and are therefore optimal models to understand how these components are altered by precocious exposure to EDCs. In particular we discuss effects of bisphenol A and methoxychlor on the dopaminergic and noradrenergic systems in rodents and the impact of these alterations. In addition, the effects of embryonic exposure to diethylstilbestrol, genistein or ethylene,1,1-dichloro-2,2-bis(p-chlorophenyl) is reviewed relative to behavioral impairment and associated alterations in the sexually dimorphic parvocellular vasotocin system in quail. We point out how sexually dimorphic behaviors are particularly useful to verify adverse developmental consequences produced by chemicals with endocrine disrupting properties, by examining either reproductive or non-reproductive behaviors
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