[The role of oxytocin and vasopressin in central nervous system activity and mental disorders].
ABSTRACT Oxytocin and vasopressin, "peptides of love and fear", except for their classic role in control of labor and breastfeeding and blood pressure regulation, are also implicated in various processes like sexual behaviours, social recognition and stress response. These hormones seems to be essential for appropriate and beneficial social interactions, play a very important role in maternal care and closeness, promote general trust and cooperation and prolong social memory. They also play a very important role in modulating fear and anxiety response, especially by regulating the hypothalamic-pituitary-adrenal axis and amygdala activity by its projections to the brain stem and hypothalamic structures. Both hormones, particularly oxytocin, appears to be activating sexual behaviour or is responsible for increased sexual arousal. Evidence from clinical trials suggests their potential role in pathogenesis of schizophrenia, depression, autism and addiction together with possible therapeutic use in the above conditions. In schizophrenia, patients with higher peripheral oxytocin levels showed less severe positive, general and social symptoms and better prosocial behaviours. Literature suggests that exogenous oxytocin may be effective as an adjunctive therapy for that illness. Some data suggest that naturally occurring autoantibodies reacting with oxytocin and vasopressin are involved in depression, eating disorders and conduct disorder genesis.
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ABSTRACT: B. F. Kania. D. Wrońska, M. Błachuta Neurobiological importances of oxytocin for humans and animals Summary Oxytocin (OT), nonapeptide secreted by two different types of neurohypophysis neurons (magnocellular and parvocellular) exclusively in mammals from the 500 million years ago it was regarding a short time ago to neurohormon what be in charge of labor preparation and the onset of labor, as well as milk let down reflex after parturition. Although, in the past decade particular investigations in neuroanatomy, neurobiology and important possibilities of oxytocinergic neurons, fibres and specific binding oxytocin receptors were taking. In addition, oxytocin can be found within central and peripheral nervous system as well as almost in the all important peripheral organ and tissues (e.g., uterus, placenta, amnion, corpus luteum, testis, heart, adrenals). Also, in these organ, the localization of the oxytocin specific receptors were confirmed. They are in the brain (amygdala, nucleus accumbens, dorsal complex nucleus of the vagus centers, hippocampus, striatum, medial prefrontal cortex, medulla), spinal cord, jejunum, adrenal glands, gonads, udder, and others. Moreover, that oxytocin have important role in the parturition and lactation, to act also as a neurotransmitter and/or neuromodulator via specific receptors in different tissues and organ. Apart from different physiological properties in the brain and different regions of organism, it can influence upon pathophysiology of the socio-mental behavior as a anxiety, aggression, stress, pain, depression, schizophrenia or autism in humans. Molecular basis of OT effects (known as exultation and happiness hormone) is based mainly on antagonistic influence to the amino acid L-glutamate, dopamine as well as GABA-ergic systems, certainly in the brain. L-glutamate, one of the most abundant excitatory neurotransmitters in mammalian CNS, is involved in the long-lasting adaptative changes that occur in response to factor exposure. Glutamate can bind to its receptors NMDA and exert its effect. Glutamate NMDA complex receptor it composed from ionotropic and metabotropic fragments. Release of excessive amounts of L-glutamate, occurring in conflict situation can provoke neurotoxic effects and neurodegenration, facilitate pain transmission or trigerring systemic hyperactivity in the stress conditions. It was demonstrated that activation of metabotropic receptors promote OT release from hypothalamo-neurophyseal systems, but direct evidence of a glutamate contribution in modulation of OT release in unanaesthetized animals is spare.
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ABSTRACT: Ghrelin, a gut-brain signal, is well known to regulate energy homeostasis, food intake and appetite foremost via hypothalamic ghrelin receptors (GHS-R1A). In addition, ghrelin activates the reward systems in the brain, namely the mesolimbic dopamine system, and regulates thereby the rewarding properties of addictive drugs as well as of palatable foods. Given that the mesolimbic dopamine system mandates the reinforcing properties of addictive drugs and natural rewards, such as sexual behaviour, we hypothesize that ghrelin plays an important role for male sexual behaviour, a subject for the present studies. Herein we show that ghrelin treatment increases, whereas pharmacological suppression (using the GHSR-1A antagonist JMV2959) or genetic deletion of the GHS-R1A in male mice decreases the sexual motivation for as well as sexual behaviour with female mice in oestrus. Pre-treatment with L-dopa (a dopamine precursor) prior to treatment with JMV2959 significantly increased the preference for female mouse compared with vehicle treatment. On the contrary, treatment with 5-hydroxythyptohan (a precursor for serotonin) prior to treatment with JMV2959 decreased the sexual motivation compared to vehicle. In separate experiments, we show that ghrelin and GHS-R1A antagonism do not affect the time spent over female bedding as measured in the androgen-dependent bedding test. Collectively, these data show that the hunger hormone ghrelin and its receptor are required for normal sexual behaviour in male mice and that the effects of the ghrelin signalling system on sexual behaviour involve dopamine neurotransmission. © 2014 The Authors. Addiction Biology published by John Wiley & Sons Ltd on behalf of Society for the Study of Addiction.Addiction Biology 12/2014; DOI:10.1111/adb.12202 · 5.93 Impact Factor