Suppression Of Aggressive Behavior Research Articles

Multifaceted suppression of aggressive behavior of thyroid carcinoma by all-trans retinoic acid induced re-differentiation

Since all-trans retinoic acid (ATRA) has shown promising results in differentiation therapy, the present study was designed to investigate the effects of ATRA on thyroid carcinoma and to evaluate the effectiveness of ATRA in redifferentiation induction of thyroid carcinoma. Therefore, we investigated cell growth rate, morphological and nuclear: cytoplasmic ratio, adherent-dependent growth, response to chemotherapy drug following differentiation, T3 and T4 measurement, and critical genes expression pattern. Papillary cell line showed more growth inhibition by ATRA, in addition, mesenchymal and spindle-shape of 8305C cells changed to polygonal. Additionally, high nuclear: cytoplasmic ratio of anaplastic decreased significantly. Redifferentiation significantly suppressed the anchorage-dependent growth in the both cell lines in a dose-dependent manner, potentiated the arsenic trioxide (ATO) effects in anaplastic and papillary cell lines. Furthermore, reduction in the expression of stemness, and invasion related genes was observed in the both cell lines. Altogether, ATRA treatment could hold the aggressive behavior of thyroid carcinoma in restraint and/or potentiate the effect of chemotherapy drug ATO.

Suppression of aggressive behaviour in juvenile Atlantic cod ( Gadus morhua) by l-tryptophan supplementation

Aggressive interactions and cannibalism of juvenile Atlantic cod may cause substantial production losses under conditions of intensive rearing. In other teleosts, chronically increased brain concentrations and turnover of the neurotransmitter serotonin (5-hydroxytryptamine, 5-HT) are associated with suppressed aggression. Further, dietary supplementation with the serotonin precursor, l-tryptophan (TRP) suppresses aggression in juvenile rainbow trout ( Onchorhyncus mykiss) and reduces cannibalism in juvenile grouper ( Epinephelus coioides). In the present study, the behavioural effect of dietary TRP supplementation was observed in pairs of juvenile Atlantic cod subjected to repeated encounters for 10 days. After 3 days, one group was given TRP-supplemented feed (28 g/kg). A significant ( P < 0.01) decrease in aggressive acts (from 40 ± 2.7/10 min to 17 ± 2.0/10 min, mean ± standard error of mean) was seen after changing to TRP-supplemented feed. The mean number of aggressive acts was also significantly ( P < 0.05) lower in the TRP-treated group (17 ± 2.0/10 min) compared to a control group not receiving TRP treatment (29 ± 3.3/10 min). A second experiment examined the effect of TRP-supplemented feed (28 g/kg) on the activity of central 5-HT, quantified as the concentration ratio between the 5-HT metabolite, 5-hydroxyindoleacetic acid (5-HIAA), and 5-HT. In this experiment, the TRP-treated group ([5-HIAA]/[5-HT] = 0.56 ± 0.04) showed elevated values ( P < 0.038) compared with the control group ([5-HIAA]/[5-HT] = 0.43 ± 0.03). In conclusion, this study shows that juvenile Atlantic cod are highly aggressive and that supplementing the feed with TRP affects central 5-HT signalling systems and reduces this behaviour.

Serotonin, but not melatonin, plays a role in shaping dominant–subordinate relationships and aggression in rainbow trout

The aim of this study was to clarify to what extent the effects of elevated dietary L-tryptophan (Trp) on aggressive behavior and stress responsiveness in rainbow trout are mediated by circulating melatonin and central serotonin (5-HT), respectively. Isolated rainbow trout were paired for 1 h a day for 7 days in order to create fish with experience of being dominant and subordinate. Following this week, the fish were tested for aggressive behavior using a resident–intruder test after which they were subjected to one of four treatments: (1) tryptophan, (2) the selective serotonin reuptake inhibitor (SSRI) citalopram, (3) melatonin, and (4) no treatment (controls). After 7 days of treatment, the fish were subjected to a second resident–intruder test. Trp-supplemented feed resulted in a suppression of aggressive behavior in fish with experience of being dominant. Moreover, fish fed Trp-supplemented feed, regardless of social experience, also displayed lower plasma cortisol levels than controls. These effects of elevated dietary Trp were closely mimicked by citalopram treatment, whereas exogenous melatonin had no effect on either aggressive behavior or plasma cortisol. Thus, the effect of elevated dietary Trp on aggressive behavior and stress responses does not appear to be mediated by melatonin even though elevated dietary intake of Trp resulted in an increase in plasma melatonin concentrations.

Neuropharmacology of an Extract derived from Convolvulus microphyllus

Neuropharmacological activities of the methanol extract of the whole plant of Shankhapushpi, Convolvulus microphyllus Sieb ex Spreng (Convolvulaceae), were studied in experimental animals. The extract was found to produce alterations in the general behaviour pattern, reduction in spontaneous motor activity, hypothermia, potentiation of pentobarbitone-sleeping time, reduction in exploratory behavioural pattern, and suppression of aggressive behaviour. The extract also showed an inhibitory effect on conditioned avoidance response and antagonism to amphetamine toxicity. These findings explicitly suggest that the whole plant extract of C. microphyllus possesses a potential CNS-depressant activity.

Low Serum Cholesterol and Suicide

"Primary prevention trials which have shown that the lowering of serum cholesterol concentrations in middle-aged subjects by diet, drugs, or both leads to a decrease in coronary heart disease have also reported an increase in deaths due to suicide or violence. There has been no adequate explanation for this association. I have reviewed the relevant published work and describe a physiological mechanism that might account for this curious finding. One of the functions of serotonin in the central nervous system is the suppression of harmful behaviour impulses. When mouse brain synaptosomal membrane cholesterol is increased there is a pronounced increase in the number of serotonin receptors. Low membrane cholesterol decreases the number of serotonin receptors. Since membrane cholesterol exchanges freely with cholesterol in the surrounding medium, a lowered serum cholesterol concentration may contribute to a decrease in brain serotonin, with poorer suppression of aggressive behaviour".

Sensory guidance in spider pre-copulatory behaviour

1. 1. In spider courtship, different tasks have to be mastered on the way to copulation. Sensory guidance is not only involved in spatial orientation, but also has to ensure sexual arousal, species recognition, and the suppression of aggressive behaviour. 2. 2. In the large tropical wandering spider Cupiennius salei (Ctenidae) and other species of the genus, precopulatory behaviour consists of three sequential phases which we call the chemical, the vibratory and the tactile phase according to the main category of stimulus used by the communicating partners. 3. 3. Both behavioural and electrophysiological experiments were performed to uncover the various roles of the different signals, emphasizing the vibratory signals which are transmitted from the sender to the receiver through the spiders' dwelling plant. 4. 4. Courtship is initiated by the arousal of the male upon contact with the pheromone laden female dragline. 5. 5. The male vibration then sent to the female is a particularly important clue in ensuring species isolation. 6. 6. Accordingly, the female's innate releasing mechanism is rather narrowly tuned to both spectral and temporal parameters contained in the male signal, and signal filtering to a considerable extent already starts in the female's vibration receptor. 7. 7. The female's own vibratory response not only informs the male of the presence of a conspecific female motivated for reproduction but also guides the male to the female's location. 8. 8. Both temporal and intensity parameters may be used for spatial orientation.

Effects of morphine hydrochloride on social encounters between male mice

The effects of a single injection of morphine hydrochloride (0.3, 0.6, or 1.25 mg/kg) or physiological saline (0.9% NaCI) on the agonistic behaviour elicited by isolation in male mice were examined. Individually housed mice were exposed to anosmic “standard opponents” 30 minutes after drug administration, and the encounters were videotaped and evaluated using an ethologically based analysis. Morphine (at 0.6 and 1.25 mg/kg) significantly and dose-dependently decreased time spent in offensive (“threat” and “attack”) and “digging” behaviours but markedly increased “non-social exploration” without a significant increase of “immobility.” The lowest dose was completely ineffective in producing changes in any of the behaviours studied. It is concluded that these results present a specific ethopharmacological profile characterized by suppression of aggressive behaviour, increase in non-social explotation, and no evident impairment of motor activity. © 1993 Wiley-Liss, Inc.

Neuropharmacological studies on Mikania cordata root extract.

Neuropharmacological studies have been conducted with the methanolic fraction of the root extract of Mikania cordata (Burm) B. L. Robinson on experimental animals. It was found to produce alteration in the general behaviour pattern, reduction in spontaneous motility, hypothermia, potentiation of pentobarbitone-sleeping time, analgesia, reduction in exploratory behaviour pattern, and suppression of aggressive behaviour. The extract also caused suppression of conditioned avoidance response and showed antagonism to amphetamine toxicity. The observations suggest that the root of M. cordata possesses a potent CNS-depressant action.

Inhibition of isolation-induced aggressive behavior with GABA transaminase inhibitors.

Administration of aminooxyacetic acid (AOAA) and gamma-acetylenic GABA (GAG) resulted in a dose-dependent suppression of aggressive behavior and a concomitant increase in brain GABA. The increase in GABA levels persisted beyond the time when AOAA and GAG exerted an anti-aggressive effect. Brain GABA levels remained significantly elevated over controls for 120 h after a single injection of AOAA and 46 h after a single dose of GAG.

Effects of Length of Time-Out from Positive Reinforcement and Schedule of Application in Suppression of Aggressive Behavior

A procedure of temporary isolation (time-out from positive reinforcement) was used as a punishment contingent on aggressive behavior in a brain-damaged child. It was found that a long time-out period administered on an intermittent schedule was relatively ineffective in controlling the undesirable behavior, while a short time-out administered consistently produced substantial suppression. Spontaneous recovery of suppression at the beginning of each experimental extinction day indicated that retention of learning may persist over many days.