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At least 289 records · Page 16Linked to original sources
PubMedDate not supplied

Cortisol excretion during the defense reaction in humans.

Twelve subjects with specific phobias were exposed to slides with a phobic or a neutral content while cortisol excretion, electrodermal activity, and distress-ratings were studied. Six subjects fearful of blood and mutilation, and six of snakes or spiders, were presented with two sets of ten different slides (phobic or neutral; 8-sec exposures, separated by 50-sec intervals) with the order of presentation balanced between days. Before and after each session, subjects rated feelings of distress, and urine samples were obtained for the determination of cortisol by radioimmunoassay. Electrodermal activity was recorded before and during slide presentation. Compared to neutral exposures, phobic slides elicited larger cortisol excretion, higher distress ratings, and greater skin-conductance responses with slower recovery. No differences between animal and blood and mutilation phobics were observed. Thus, humans having specific phobias exhibit pituitary-adrenal cortical arousal during the defense reaction elicited by slides of their phobic objects.

Adult↗
PubMedDate not supplied

[Evoked potentials of the brain limbic structures during a change in the motivational state of dogs and during the realization of unconditioned reflex reactions].

In experiments on 6 dogs it has been shown that in the EPs led from the hippocampus in response to electrostimulation of limbic structures and from the latters at the hippocampus stimulation, initial negativity, after positivity and late negative wave are the most stable components. At transition from one functional state to another two latter waves are subjected to the greatest changes. Amplitude-temporal characteristics of intralimbic EPs depend on the level and type of motivation, degree of emotional stress and properties of conditioned reaction.

Animals↗
PubMed1975

Effects of cannabis resin on social behaviour in the laboratory mouse.

The effects of several dose levels of cannabis have been studied by an ethiological analysis of encounters between male mice injected with the drug and partners injected with Tween-saline. The duration of immobility was directly related to the logarithm of the dose of cannabis given. The ratio of flight in the treated animals to aggression in those mice with which they were paired showed a progressive increase as the dose of cannabis was raised from 4-50 mg/kg. A straight line relationship was found to exist between the logarithm of flight/aggression and logarithm of the dose of cannabis administered. Non-social activity and social investigation were decreased by the administration of cannabis; this was due to the time spent by the treated animals in immobility. Aggression was not significantly altered. Many mice given doses of 25-100 mg cannabis/kg showed an ataxic gait and the Straub tail reaction.

Aggression↗
PubMed2003

Effects of Hypericum perforatum and paroxetine in the mouse defense test battery.

Since (a) Hypericum perforatum shows anxiolytic-like effect in some animal models, (b) antidepressant drugs (AD) have been used as the main drug treatment for panic disorder (PD), (c) AD are also effective in generalized anxiety disorder (GAD), and (d) H. perforatum exhibits antidepressant activity, it was hypothesized that H. perforatum might possess an antipanic-like and/or anxiolytic-like effect. Previous studies with the mouse defense test battery (MDTB) have suggested that this model may be useful for the investigation of anxiolytic-like and antipanic-like compounds. Thus, the aim of the present study was to evaluate the effect of H. perforatum extract in the MDTB. The effect of acute, subchronic (7 days), and chronic (21 days) H. perforatum (150 and 300 mg/kg) extract administration was evaluated in mice submitted to the MDTB. Paroxetine (5 mg/kg), a selective serotonin re-uptake inhibitor with anxiolytic and antipanic effect, was used as a positive control. The results showed that 21 days of repeated administration of H. perforatum 300 mg/kg and paroxetine 5 mg/kg reduced flight reactions (number of avoidances, avoidance distance, and overall flight speed) to the presence of the predator. While the effect of paroxetine confirms that MDTB is useful for the detection of antipanic-like drugs, the effect of H. perforatum suggests a putative antipanic-like effect for this extract. Moreover, after 21 days of repeated administration, paroxetine increased the number of approaches/withdrawals and reduced the number of upright postures, suggesting a partial anxiolytic-like effect, while H. perforatum only reduced the number of upright postures. The present results suggest anxiolytic-like and antipanic-like effects of H. perforatum extract. However, it should be emphasized that the risk assessment (the main index of anxiety) was not affected by the extract, while the attack reactions were only weakly modified.

Animals↗
PubMed1979

[Change in the cholesterol and triglyceride content in the blood in self-stimulation and avoidance reactions].

The changes in the blood serum cholesterol and triglyceride content were studied or rabbits of both sexes during reactions of self-stimulation and avoidance. Self-stimulation was accompanied by a significant decrease in the blood serum cholesterol and triglyceride content. During the reaction of avoidance the character of the cholesterol changes varied. The reaction of avoidance of the "agression" type was accompanied by elevated blood serum cholesterol content, whereas the reaction of the "fear" type was associated with a decrease in its content. The maximal changes in the cholesterol and triglyceride content as compared to the initial level were observed in all types of the reactions 15--30 minutes following stimulation.

Animals↗
PubMedDate not supplied

[Oligopeptides in mechanisms of emotional reactions].

Oligopeptides participate in central mechanisms of emotional reactions. The oligopeptides are found, exhibiting at definite doses the activating and inhibitory effects on behavioral and vegetative manifestations of negative and positive emotional reactions.

Action Potentials↗
PubMedDate not supplied

[Neuronal spike activity in the sensomotor region of the cerebral cortex upon direct stimulation of emotionally "positive" and "negative" zones of the hypothalamus].

The effect of electrical stimulation of emotionally positive and negative hypothalamic areas on the unit activity of the sensorimotor cortex in rats was studied in order to elucidate physiological mechanisms of emotions as an important factor organizing purposeful animal behaviour. It was found that such an effect is primarily of inhibitory nature and that it does not carry specific information on biological sign of emotion. It is suggested that the formation of adequate behavioural reactions in different emotional states occurs at earlier stages.

Animals↗
PubMed1988

Defense reaction induced by microinjections of bicuculline into the inferior colliculus.

Behavioral and autonomic effects of microinjections of bicuculline--a GABA receptor antagonist--into ventral aspects of the inferior colliculus (IC) produced a behavioral activation together with jumps. This activation was similar to escape behavior that has been induced from periventricular structures although it was neither as explosive as that observed from the dorsal periaqueductal gray matter (DPAG) nor as coordinated as that obtained from the medial hypothalamus (MH). In anesthetized rats, microinjection of bicuculline into the IC produced a clear rise in mean arterial blood pressure and in heart rate. These effects reached a maximum after 10 min and subsided within 20 min after injection. GABA receptor blockade in the IC of detelencephalated rats also resulted in escape behavior qualitatively similar to that observed in intact animals. These results suggest that in addition to the central gray and medial hypothalamus, GABA also exerts a tonic inhibitory action on neurons of the IC implicated in the generation or elaboration of aversive responses.

Animals↗
PubMed1976

Habituation and conditioning of the defense reactions and their cardiovascular components in cats and dogs.

Cardiovascular and behavioural responses elicited by novel, noxious or aversive stimuli have been studied in dogs and cats. Hindlimb blood flow, heart rate and arterial blood pressure increased in dogs when an orienting response was elicited by a novel stimulus (a sound). Similar cardiovascular responses occurred in dogs to mild noxious stimulus and in cats displaying a threatening posture when confronted by a dog. The cardiovascular components of the orienting response to a sound habituated with repetition of the sound. In two dogs however sensitization (increase) of the response occurred with reped by repetition of the confrontations: the vasodilation in the muscles waned and eventually was replaced by vasoconstriction while the cardiac acceleration and pressor response persisted. The threatening response was the most persistent. The modification of the behavioural and cardiovascular aspect of the response was not developing in parallel. The cardiovascular pattern was altered before any apparent changes of the behavioural pattern occurred. The cardiovascular responses of the noxious stimulus in dogs and cardiovascular components of the defence reaction in cats were readily conditioned to a sound. The possible role of the modification of the cardiovascular pattern in defence reactions in pathogenesis of hypertension is discussed.

Animals↗
PubMed1994

Behavioral and physiological effects of different water depths in the forced swim test.

Rats were immersed for 15 min in a forced swim test in cylinders filled with water to a depth of 20 or 35 cm. The following day, they were reimmersed for a 5-min test period at one of these two depths. Water immersion, regardless of water depth, resulted in increased serum lactate and corticosterone levels, reduced serum carbon dioxide and potassium levels, a metabolic acidosis, and an increase in the phosphorus/potassium ratio. Testing at the greater water depth resulted in lower immobility times, higher lactate and lower carbon dioxide levels, a greater metabolic acidosis, and a higher phosphorus/potassium ratio than testing at the shallower depth. Water depth did not significantly affect corticosterone or potassium responses. None of the interactions between day 1 and day 2 depth was significant. The correlation between immobility time and corticosterone was very low, whereas the correlation with lactate, carbon dioxide, anion gap, and the phosphorus/potassium ratio were high. The inference from these results is water depth at time of testing affects the rat's behavioral and physiological reactions in the forced swim test and prior exposure to water at any depth does not.

Animals↗