Page not availableNeurosterokdi recettore neurosteroidi e gaba A recettore ionotropo uno dei due recettori per il gaba acido -amminobutirrico che sono presenti a livello del sistema nervoso, assieme. La how do nasal corticosteroid sprays work di un tranquillante naturale influisce sulla depressione. La scoperta di Graziano Pinna, oristanese, scienziato e docente alla Universit dell. La glicina un neurotrasmettitore inibitorio nel sistema nervoso centrale, specialmente nel midollo spinale e nel tronco encefalico, dove. Negli ultimi decenni si assistito ad un notevole incremento di reati, e di alcuni in particolare, agevolati dallutilizzo di sostanze psicoattive, tanto. Neurosteroidi e gaba Neurosteroidi e gaba tpr Category:
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Neurosteroids , also known as neuroactive steroids , are endogenous or exogenous steroids that rapidly alter neuronal excitability through interaction with ligand-gated ion channels and other cell surface receptors. In addition to their actions on neuronal membrane receptors, some of these steroids may also exert effects on gene expression via nuclear steroid hormone receptors.
Neurosteroids have a wide range of potential clinical applications from sedation to treatment of epilepsy  and traumatic brain injury. Based on differences in activity and structure , neurosteroids can be broadly categorized into several different major groupings. These neurosteroids exert inhibitory actions on neurotransmission. These neurosteroids have excitatory effects on neurotransmission.
Major examples include the pregnanes pregnenolone sulfate PS , epipregnanolone , and isopregnanolone sepranolone , the androstanes dehydroepiandrosterone DHEA; prasterone , and dehydroepiandrosterone sulfate DHEA-S; prasterone sulfate , and the cholestane 24 S -hydroxycholesterol NMDA receptor-selective; very potent.
Pheromones are neurosteroids that influence brain activity, notably hypothalamic function, via activation of vomeronasal receptor cells. They include the androstanes androstadienol , androstadienone , androstenol , and androstenone and the estrane estratetraenol. Certain other endogenous steroids, such as pregnenolone ,  progesterone ,   estradiol ,  and corticosterone are also neurosteroids.
However, unlike those listed above, these neurosteroids do not modulate the GABA A or NMDA receptors, and instead affect various other cell surface receptors and non-genomic targets. Also, many endogenous steroids, including pregnenolone, progesterone, corticosterone, deoxycorticosterone , DHEA, and testosterone , are metabolized into other neurosteroids, effectively functioning as so-called pro neurosteroids.
Neurosteroids are synthesized from cholesterol , which is converted into pregnenolone and then into all other endogenous steroids. Neurosteroids are produced in the brain after local synthesis or by conversion of peripherally-derived adrenal steroids or gonadal steroids.
They accumulate especially in myelinating glial cells, from cholesterol or steroidal precursors imported from peripheral sources. Some major known biological functions of neurosteroids include modulation of neural plasticity ,  learning and memory processes,  behavior ,   and seizure susceptibility ,  as well as responses to stress , anxiety , and depression.
Acute stress elevates the levels of inhibitory neurosteroids like allopregnanolone, and these neurosteroids are known to counteract many of the effects of stress. As such, it has been suggested that one of the biological functions of these neuromodulators may be to help maintain emotional homeostasis.
It is thought that fluctuations in the levels of inhibitory neurosteroids during the menstrual cycle and pregnancy play an important role in a variety of women's conditions , including premenstrual syndrome PMS , premenstrual dysphoric disorder PMDD , postpartum depression PPD , postpartum psychosis , and catamenial epilepsy.
Elevated levels of inhibitory neurosteroids, namely allopregnanolone, can produce paradoxical effects, such as negative mood , anxiety , irritability , and aggression. Several synthetic neurosteroids have been used as sedatives for the purpose of general anaesthesia for carrying out surgical procedures.
The best known of these are alphaxolone , alphadolone , hydroxydione , and minaxolone. Hydroxydione proved to be a useful anaesthetic drug with a good safety profile, but was painful and irritating when injected probably due to poor water solubility. This led to the development of newer neuroactive steroids. The next drug from this family to be marketed was a mixture of alphaxolone and alphadolone, known as Althesin.
This was withdrawn from human use due to rare but serious toxic reactions, but is still used in veterinary medicine. The next neurosteroid anaesthetic introduced into human medicine was the newer drug minaxolone, which is around three times more potent than althesin and retains the favourable safety profile, without the toxicity problems seen with althesin.
However this drug was also ultimately withdrawn, not because of problems in clinical use, but because animal studies suggested potential carcinogenicity and since alternative agents were available it was felt that the possible risk outweighed the benefit of keeping the drug on the market.
The neurosteroid ganaxolone , an analog of the progesterone metabolite allopregnanolone, has been extensively investigated in animal models and is currently in clinical trials for the treatment of epilepsy. Neurosteroids, including ganaxolone have a broad spectrum of activity in animal models.
A randomized, placebo controlled, week phase 2 clinical trial of orally administered ganaxolone in adults with partial onset seizure demonstrated that the treatment is safe, well tolerated and efficacious.
Data from non-clinical studies suggest that ganaxolone may have low risk for use in pregnancy. In addition to use in the treatment of epilepsy, the drug has potential in the treatment of a broad range of neurological and psychiatric conditions. Proof-of-concept studies are currently underway in posttraumatic stress disorder and fragile X syndrome. Researchers have suggested the use of so-called "neurosteroid replacement therapy" as a way of treating catamenial epilepsy with neuroactive steroids such as ganaxolone during the period of the menstrual cycle when seizure frequency increases.
Allopregnanolone SAGE is under development as an intravenous therapy for the treatment of super-refractory status epilepticus , postpartum depression , and essential tremor. Certain antidepressant drugs such as fluoxetine and fluvoxamine , which are generally thought to affect depression by acting as selective serotonin reuptake inhibitors SSRIs , have also been found to normalize the levels of certain neurosteroids which are frequently deficient in depressed patients at doses that are inactive in affecting the reuptake of serotonin.
This suggests that other actions involving neurosteroids may also be at play in the effectiveness of these drugs against depression. Benzodiazepines may influence neurosteroid metabolism by virtue of their actions on translocator protein TSPO; "peripheral benzodiazepine receptor".
Factors which affect the ability of individual benzodiazepines to alter neurosteroid levels may depend upon whether the individual benzodiazepine drug interacts with TSPO. Some benzodiazepines may also inhibit neurosteroidogenic enzymes reducing neurosteroid synthesis. From Wikipedia, the free encyclopedia. Progress in Brain Research. Jasper's Basic Mechanisms of the Epilepsies [Internet].
The Journal of Neuroscience. The European Journal of Neuroscience. Mini Reviews in Medicinal Chemistry. Doty 12 February The Neurology of Olfaction. The American Journal of Psychiatry. Trends in Endocrinology and Metabolism. International Review of Neurobiology. Annals of the New York Academy of Sciences. Scientific Foundations of Clinical Practice.
Marcel Dekker, New York, ; The Journal of Pharmacology and Experimental Therapeutics. Complementary and Alternative Therapies for Epilepsy. New mechanistic, therapeutical and predictive approaches". British Journal of Pharmacology. Reddy D, Rogawski MA Jasper's Basic Mechanisms of the Epilepsies 4th edition ed. National Center for Biotechnology Information.