The Effect of Acute and Repeated Stress on CRH-R1 and CRH-R2 mRNA Expression in Pituitaries of Wild Type and CRH Knock-Out Mice.

The activation of the HPA axis is the endocrine measure of stress responsiveness that is initiated by corticotropin-releasing hormone (CRH). CRH exerts its effects via CRHR1 and CRH-R2 receptors coupled to the cAMP signaling system and this process involves transcription factor cAMP-responsive element-binding protein (CREB).This study investigated the role of CRH and the possible involvement of CREB in gene regulation of CRH receptor, under basal conditions and after stress application in the pituitary.

Effect of Stress on the Expression of Galanin Receptors in Rat Heart.

Neuropeptide galanin, galanin-like peptide and galanin receptors 1, 2 and 3 are a crucial part of the so-called galaninergic system. Our previous studies have shown the possible role of this system in mood modulation, especially regarding stress. So far, the galanin receptors have been found in different tissues including brain and heart.

The galanin and galanin receptor subtypes, its regulatory role in the biological and pathological functions.

The multitalented neuropeptide galanin was first discovered 30 years ago but initially no biologic activity was found. Further research studies discovered the presence of galanin in the brain and some peripheral tissues, and galanin was identified as a modulator of neurotransmission in the central and peripheral nervous system. Over the last decade there were performed very intensive studies of the neuronal actions and also of nonneuronal actions of galanin.

The Effect of Stress on the Galaninergic System in the Rat Adenohypophysis: mRNA Expression and Immunohistochemistry of Galanin Receptors.

The neuropeptide galanin is a widely distributed neurotransmitter/neuromodulator that regulates a variety of physiological processes and also participates in the regulation of stress responses. The effect of stress is dependent on the activity of the hypothalamic-adenohypophyseal-adrenal axis. Although the adenohypophysis is a crucial part of this axis, galanin peptides and their receptors have not yet been identified in this part of the pituitary after activation of the stress response.

Effects of immobilizations stress with or without water immersion on the expression of atrial natriuretic peptide in the hearts of two rat strains.

Atrial natriuretic peptide (ANP) is produced and released by mammalian cardiomyocytes and induces natriuresis, diuresis, and lowering of blood pressure. The present study examined localization of ANP and a possible role of the hypothalamic-pituitary-adrenal axis (HPA) activity on the expression of proANP gene in the heart. The Sprague Dawley (SD) and Lewis (LE) rat strains were used.

Electronic and vibrational optical activity of several peptides related to neurohypophyseal hormones: disulfide group conformation.

Electronic and vibrational optical activity of the set of neurohypophyseal hormones and their analogs was investigated to clarify the S-S bond solution conformation. The selected compounds include oxytocin (I), lysine vasopressin (II), arginine vasopressin (III), and their analogs (IV-IX), differing widely in their pharmacological properties. We have extended the already known electronic circular dichroism data by new information provided by vibrational circular dichroism (VCD) and Raman optical activity (ROA).

Effects of acute stressors on the expression of oxytocin receptor mRNA in hearts of rats with different activity of HPA axis.

Objectives: Cardiovascular system is regulated by a diverse array of hormones, neurotransmitters and neuropeptides. Oxytocin and its receptors (OTR) were also shown to regulate cardiovascular functions and this hormone was even called cardiovascular hormone. In recent publication, we demonstrated the expression of mRNA of OTR by real-time quantitative PCR (RT qPCR) in all rat heart compartments.

Expression of heart oxytocin receptor and its mRNA in two rat strains with different activity of HPA axis.

Objectives: Oxytocin (OT) is a neuropeptide acting both as a peripheral hormone and in the brain as neurotransmitter and neuromodulator. In addition to its well-known effects on milk-ejection and uterine contraction, OT was shown to exert neuroendocrine regulation of heart functions. The aim of this study was to investigate the expression of mRNA of OT receptors (OTR) in rat hearts by real-time quantitative PCR (qPCR).

Galanin modulating effect on restraint stress-induced short- and long-term behavioral changes in Wistar rats.

The neuropeptide galanin has been recognized as a possible neurotransmitter/neuromodulator, and in addition has been implicated in anxiety- and depression-related behaviors. The present study demonstrates increased locomotion and rearing after galanin (0.3mg/kg) that was given intraperitoneally (i.

[Memory and its dysfunction].

In the last decades interdisciplinary research of memory takes place and it connects regions as cognitive psychology and neuroscience. Learning and memory are theoretical concepts, which enable to explain the fact that personal experience influences the behavior of the particular person. Memory has neuronal representation, which enables recollection of obtained experiences and information, and subsequently enables changes in behavior.

[Neurobiology of memory].

In the introduction we summarized basic information about memory and indicated studies, which were milestones in the study of memory. Basic studies of memory are reviewed and neurobiological approach is highlighted. The aim of this investigation is to find the relationship among basic facts about memory and what are the underlying mechanisms.

Oxytocin and carbetocin ameliorating effects on restraint stress-induced short- and long-term behavioral changes in rats.

Objectives: Carbetocin (CBT), an oxytocin (OXY) analog, was designed to exert prolonged peripheral actions. It has also been proposed as potential therapeutic mean in certain psychiatric disorders where OXY role has been implicated. This study examined the effects of both peptides on behavior of naive and restraint stress exposed rats in the open field (OF) and elevated plus maze (EPM) tests.

Role of oxytocin/oxytocin receptor system in regulation of cell growth and neoplastic processes.

Novel sites of oxytocin receptor expression have recently been detected in central nervous system, cardiomyocytes, endothelial cells, various carcinoma cells, etc. These and other discoveries have greatly expanded the classical biological roles of oxytocin, which are stimulation of uterine smooth muscle contraction at parturition and milk ejection during lactation. It is becoming clear that the great diversity of oxytocin actions in the brain and peripheral organs is paralleled by activation of a diversity of signalling pathways.

Oxytocin and carbetocin effects on spontaneous behavior of male rats: modulation by oxytocin receptor antagonists.

Objectives: Oxytocin (OXY) in addition to peripheral actions has many central regulatory functions which can be studied on animal models. In the present study we examined in rats, which behavioral actions of OXY and long-acting carba-analog of OXY carbetocin (CBT) in the open-field can be inhibited by OXY-receptor antagonists. Our interest focused on the behavioral patterns considered indicative of anxiety-related behavior.

Modulary effects of oxytocin and carbetocin on stress-induced changes in rat behavior in the open-field.

Oxytocin (OXY) has been shown to attenuate some of the physiological and behavioral alterations appearing in stressed rats. Carbetocin (CBT), an oxytocin analog [deamino-1-monocarba-(2-O-methyltyrosine)-oxytocin], was designed to exert prolonged action. In the present study we investigated the impact of these peptides on the behavioral changes in rats exposed repeatedly to restraint stressors.

Novel and simple behavioral paradigm for assessing anxiety in rats: effect of diazepam.

Objectives: Anxiety is an emotional state experienced by people, and is not readily modeled in animals. In order to extend till now ethologically derived paradigms used in the evaluation of anxiety and fear in rodents, a modified open-field was designed.

Methods: Spontaneous behavior of male rats was investigated in the elevated arena; the bottom was divided by inter-space of different width (2, 4, 6, 8 and 10 cm) into two identical parts.

Corticotropin-releasing hormone receptor subtypes in the rat anterior pituitary after two types of restraint stress.

The stress response in anterior pituitary (AP) is mediated by corticotropin-releasing hormone (CRH) acting through CRH-R1 and -R2, however, the function of CRH-R2 in AP is still not fully elucidated. We used 1-h long restraint (IMO) as well as restraint combined with water immersion (IMO+C). Using real-time PCR we quantified mRNA expression of CRH-R1, CRH-R2alpha-soluble and -insoluble, and cAMP response element binding (CREB), with reference gene GAPDH.

Dipeptide "alaptide" prevented impairments in spontaneous behavior produced with trimethyltin in male rats.

Objectives: On the animal model of trimethyltin (TMT) induced behavioral deficits the effect of chronic treatment with spirocyclic dipeptide cyclo/alanyl-l-amino-l-cyclopentane-carbonyl (alaptide, AL) was evaluated in adult male rats.

Methods: Changes in the spontaneous behavioral repertoire were investigated in the open-field test on Day 21 (Session 1) and Day 28 (Session 2) after a single oral TMT administration.

Results: In Experiment 1, rats given the highest TMT dose (7.

Effects of melanotan II, a melanocortin agonist, on grooming and exploration in rats after repeated restraint/immobilization.

2mg/kg melanotan II (MTII, administered i.p.), a cyclic peptide analog of alpha-melanocyte stimulating hormone, at a single dose increased grooming in naive rats placed in an unfamiliar open-field device without changing locomotion or rearing.

[Some newer findings concerning oxytocin receptor signaling].

Nonapeptide oxytocin (OT) is known primarily as an inducer of uterine contraction and milk ejection. Recently, there have been described its regulatory actions on various brain functions and on many peripheral actions including regulation of cell growth. The diversity of OT actions produced by the stimulation of OT receptors (OTR) is paralleled by a diversity of its signaling pathways.

Effects of two types of restraint stress on spontaneous behavior of Sprague-Dawley and Lewis rats.

The purpose of this study was to evaluate the action of two types of stressors in Sprague-Dawley (S-D) and Lewis (LEW) rats differing in their hypothalamic-pituitary-adrenal axis activity on locomotion and rearing in an open space. Exposure to restraint immobilization alone (IMO) or this immobilization combined with cold water (22 degrees C) immersion (IMO+C) lasted for 1 h and started 2 or 5 h before the test. To evaluate the acute and persisting effects of both stressors, four trials were performed in one-week intervals; rats were exposed to the stressors in trial 1 and 3.

Dynamics of immediate early gene and neuropeptide gene response to prolonged immobilization stress: evidence against a critical role of the termination of exposure to the stressor.

Stress-induced expression of immediate early genes (IEGs) appears to be transient even if the exposure to the stressor persists. However, there are some exceptions which suggest that particular characteristics of stressors can affect the dynamics of IEG expression. We studied in selected telencephalic, diencephalic and brainstem regions the mRNA levels of two clearly distinct IEGs (c-fos and arc) during prolonged exposure to a severe stressor such as immobilization (IMO) and after releasing the rats from the situation.

Timing of stress and testing influence the long-lasting behavioral performance in rats.

Three exposures (Days 1, 2 and 3) of rats to immobilization or immobilization combined with cold induced an alteration of exploratory behavior in an open space arena. When tested 1h after both stressors exposure, rats displayed a decrease in locomotor and rearing score. The deficit disappeared when rats were tested five days later and the performance remained unchanged in trials performed on days 9, 10, 15, 22 and 29 of the study.

Differences in the brain expression of c-fos mRNA after restraint stress in Lewis compared to Sprague-Dawley rats.

In order to study the contribution of genetic factors to the pattern of stress-induced brain activation, we studied the expression of c-fos mRNA, a marker of neuronal activity, in male Sprague-Dawley and Lewis strains, the latter being known to have a deficient responsiveness of the hypothalamic-pituitary-adrenal (HPA) axis. Immobilization (IMO) alone or combined with the immersion into water at 21 degrees C was applied for 15 or 60 min. The expression of c-fos mRNA was quantified by in situ hybridization in those brain areas that represent important parts of neuronal circuits activated by stress: medial prefrontal cortex, medial amygdala, lateral septum ventral part, paraventricular nucleus of the hypothalamus and locus coeruleus.

Effects of stress and of amphetamine on passive avoidance conditioning in rats.

This study examined the effects of immobilization stress combined with water immersion (ICS) and/or amphetamine (AM) on different memory phases in the passive avoidance task in rats. The performance of rats was evaluated in the retention tests 24 and 48 h after a single acquisition trial. ICS exposure lasting 1 h impaired retention of the learned avoidance response if applied 2 to 4 h before or immediately after training.