Previous studies have demonstrated that stress may increase prodynorphin gene expression, and kappa opioid agonists suppress drug reward. Therefore, we tested the hypothesis that stress-induced release of endogenous dynorphin may mediate behavioral responses to stress and oppose the rewarding effects of cocaine. C57Bl/6 mice subjected to repeated forced swim testing (FST) using a modified Porso...

Individuals within monogamous species form bonds that may buffer against the negative effects of stress on physiology and behavior. In some species, involuntary termination of the mother-offspring bond results in increased symptoms of negative affect in the mother, suggesting that the parent-offspring bond may be equally as important as the pair bond. To our knowledge, the extent to which affec...

There is evidence to support a relationship between stress, depression, and alcoholism. Animal models have been developed to ascertain the impact of stress on depressive-like symptoms and ethanol intake. The swim test susceptible (SUS) line of rats selectively bred for enhanced susceptibility to stress-induced immobility in the forced swim test (FST) also show high voluntarily ethanol intake co...

The central nucleus of the amygdala (CEA) is selectively involved in the passive component of the behavioral (immobility) and the accompanying parasympathetic response during conditioned, stressful environmental challenges. Vasopressinergic mechanisms in the brain seem to play a role in these stress responses. The effects of the neuropeptides arginine-8-vasopressin (AVP) and oxytocin (OXT) on m...

The aim of this study was to investigate beak surface temperature changes stress induced by fear resulting from tonic immobility using infrared thermography in laying hens. It also examined whether temperatures differed among brown and white lines. based on 89 hens both lines: 45 White Leghorn birds 44 Hy-Line birds. Beak measured with immediately before after testing. average obtained the uppe...

Analysis of the meaning of the immobility time in swimming experimental models The aim of this work was to evaluate if the meaning of immobility (helplessness or adaptation) depends on the experimental model (forced swimming test or swimming stress). Immobility time (IT) and glycogen mobilization of rats submitted to swimming session were analyzed in two protocols: swimming stress (SS) and forc...

The purpose of this study was to analyze the effect of auditory enrichment (by means of classical music) or physical enrichment (by means of hanging colored string bunches and barley grains on the floor) on tonic immobility duration, heterophil to lymphocyte ratio, and fluctuating asymmetry (FA) in chicks of several layer breeds. In experiment 1, 192 chicks from 8 Spanish breeds and 1 White Leg...

OBJECTIVE In this study, the effect of maternal deprivation (MD) and chronic unpredictable stress (CUS) in inducing depressive behaviors and associated molecular mechanism were investigated in rats. METHODS Maternal deprivation was established by separating pups from their mothers for 6 hours daily from postnatal day 1 to day 14. Chronic unpredictable stress was established by water deprivati...

The forced swim test (FST) is commonly employed to test the potency of drugs to reduce immobility as an indicator of anti-despair. Certainly, antidepressant drugs reduce the total time of immobility and enlarge the latency to the first immobility period. FST is preceded by the open field test (OFT) to discard any influence of changes in general motor activity that could interfere with immobilit...

In young male Wistar rats sudden silence superimposed on low intensity background noise evokes a relative decrease in heart rate. This bradycardia is accompanied by immobility behavior. In the present study, involving young (3 month), late-adult (14 month), aged (20 month), and senescent (25 month) rats the magnitude of the stress-induced bradycardia shows an age-related reduction while the beh...