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Activating Effects (activating + effects)
Selected AbstractsEarly adolescents show enhanced acute cocaine-induced locomotor activity in comparison to late adolescent and adult ratsDEVELOPMENTAL PSYCHOBIOLOGY, Issue 2 2008Kimberly A. Badanich Abstract Initiation of drug use during adolescence is associated with an increased probability to develop a drug addiction. The present study examined dose,response effects of cocaine (0, 5, 10, or 20 mg/kg, i.p.) on locomotor activity in early adolescent (postnatal day (PND) 35), late adolescent (PND 45), and young adults (PND 60) by measuring total distance moved (TDM) and frequency of start,stops. In response to 20 mg/kg cocaine, early adolescents showed the greatest cocaine-induced increase in TDM in comparison to late adolescent and adult rats. At this same dose, early adolescents showed the greatest cocaine-induced attenuation of start,stops relative to older rats. Results suggest that early adolescents engage in more cocaine-induced locomotor activity and less stationary behavior indicating that early adolescents are more sensitive to locomotor activating effects of high dose cocaine than older rats. © 2008 Wiley Periodicals, Inc. Dev Psychobiol 50: 127,133, 2008. [source] Comparative studies on the functional roles of N- and C-terminal regions of molluskan and vertebrate troponin-IFEBS JOURNAL, Issue 17 2005Hiroyuki Tanaka Vertebrate troponin regulates muscle contraction through alternative binding of the C-terminal region of the inhibitory subunit, troponin-I (TnI), to actin or troponin-C (TnC) in a Ca2+ -dependent manner. To elucidate the molecular mechanisms of this regulation by molluskan troponin, we compared the functional properties of the recombinant fragments of Akazara scallop TnI and rabbit fast skeletal TnI. The C-terminal fragment of Akazara scallop TnI (ATnI232,292), which contains the inhibitory region (residues 104,115 of rabbit TnI) and the regulatory TnC-binding site (residues 116,131), bound actin-tropomyosin and inhibited actomyosin-tropomyosin Mg-ATPase. However, it did not interact with TnC, even in the presence of Ca2+. These results indicated that the mechanism involved in the alternative binding of this region was not observed in molluskan troponin. On the other hand, ATnI130,252, which contains the structural TnC-binding site (residues 1,30 of rabbit TnI) and the inhibitory region, bound strongly to both actin and TnC. Moreover, the ternary complex consisting of this fragment, troponin-T, and TnC activated the ATPase in a Ca2+ -dependent manner almost as effectively as intact Akazara scallop troponin. Therefore, Akazara scallop troponin regulates the contraction through the activating mechanisms that involve the region spanning from the structural TnC-binding site to the inhibitory region of TnI. Together with the observation that corresponding rabbit TnI-fragment (RTnI1,116) shows similar activating effects, these findings suggest the importance of the TnI N-terminal region not only for maintaining the structural integrity of troponin complex but also for Ca2+ -dependent activation. [source] In-vitro effect of flavonoids from Solidago canadensis extract on glutathione S-transferaseJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 2 2006Pál Apáti Solidago canadensis is typical of a flavonoid-rich herb and the effect of an aqueous ethanol extract on glutathione-S-transferase (GST) activity using HepG2 cells was compared with those of the flavonol quercetin and its glycosides quercitrin and rutin, found as major constituents. The composition of the extract was determined by HPLC and rutin was found to be the major flavonoidal component of the extract. Total GST activity was assessed using 1-chloro-2,4-dinitrobenzene as a substrate. The glycosides rutin and quercitrin gave dose-dependent increases in GST activity, with a 50% and 24.5% increase at 250 mm, respectively, while the aglycone quercetin inhibited the enzyme by 30% at 250 mm. The total extract of the herb gave an overall dose-dependent increase, the fractions corresponding to the flavonoids showed activating effects while those containing caffeic acid derivatives were inhibitory. The activity observed corresponds to that reported for similar compounds in-vivo using rats, thus the HepG2 cell line could serve as a more satisfactory method of assessing the effects of extracts and compounds on GST. [source] Is the Strength of Implicit Alcohol Associations Correlated with Alcohol-induced Heart-rate Acceleration?ALCOHOLISM, Issue 8 2006Esther Van Den Wildenberg Background: Heart rate (HR) acceleration during the ascending limb of the blood alcohol curve has proven to be a reliable measure of the sensitivity to the activating effects of alcohol. In this study, we investigated the correlation between an ethanol-induced cardiac change and the strength of implicit alcohol-related arousal and approach associations and attentional bias for alcohol-related stimuli in heavy drinkers. These 3 types of implicit alcohol-related cognitions have been proposed to reflect the strength of incentive sensitization that is experienced after repeated alcohol use. Methods: Forty-eight heavy drinking men performed a modified version of the Implicit Association Test (IAT) to measure their implicit alcohol arousal and approach,avoidance associations. A modified version of the emotional Stroop was used to measure attentional bias for alcohol-related stimuli (blocked and unblocked). Next, a high dose of alcohol (1.0 mL/kg body weight 95% USP alcohol) was administered in a short period of time. Resting baseline HR, blood alcohol concentrations, mood, and craving for alcohol were assessed before alcohol administration and for 2 hours post,alcohol consumption. Results: Contrary to our hypothesis, a negative association was found between implicit arousal associations and alcohol-induced HR change. This indicates that strong arousal associations were correlated with a decrease in alcohol-induced HR. Approach associations and attentional bias were not correlated with alcohol-induced HR change, but both were correlated positively with each other. Conclusions: Alcohol-arousal associations and other implicit cognitions (attentional bias, approach associations) are not positively related to individual differences in the sensitivity to alcohol's activating effects, at least not in the present sample consisting primarily of family history-negative heavy drinkers. [source] Deletion of the ,7 Nicotinic Receptor Subunit Gene Results in Increased Sensitivity to Several Behavioral Effects Produced by AlcoholALCOHOLISM, Issue 3 2005Barbara J. Bowers Background: The finding that most people with alcoholism are also heavy smokers prompted several research groups to evaluate the effects of ethanol on neuronal nicotinic acetylcholine receptor (nAChR) function. Data collected in vitro indicate that physiologically relevant concentrations of ethanol inhibit the functional activation of homomeric ,7 nAChRs, which are one of the most abundant nAChR subtypes expressed in the mammalian brain. The studies outlined here used ,7 gene knockout (null mutant) mice to evaluate the potential role of ,7 nAChRs in modulating selected behavioral and physiological effects produced by ethanol. Methods: Current evidence indicates that many responses to ethanol are not genetically correlated. Therefore, the authors measured the effects of acute administration of ethanol on several behaviors that are altered by both ethanol and nicotine: two tests of locomotor activity, acoustic startle, prepulse inhibition of acoustic startle, and body temperature. Ethanol-induced durations of loss of righting reflex and ethanol elimination rates were also determined. These studies used null mutant (,7,/,) and wild-type (,7+/+) mice. Results: Relative to ,7+/+ mice, ,7,/, mice were more sensitive to the activating effects of ethanol on open-field activity, ethanol-induced hypothermia, and duration of loss of the righting response. Deletion of the ,7 gene did not influence the effects of ethanol on Y-maze crossing or rearing activities, acoustic startle, or prepulse inhibition of startle. Gene deletion did not alter ethanol metabolism. Conclusions: These results indicate that some but not all of the behavioral effects of ethanol are mediated in part by effects on nAChRs that include the ,7 subunit and may help to explain the robust association between alcohol consumption and the use of tobacco. [source] Acute Effects of Ethanol on Behavior of Adolescent Rats: Role of Social ContextALCOHOLISM, Issue 3 2001Elena I. Varlinskaya Background: First experiences with alcohol in humans occur predominantly in adolescence, and to a large extent the attractiveness of alcohol at this age is based on its ability to facilitate certain forms of social behavior (social facilitation). Adolescence is strongly marked by a focus on peer relationships, and the social nature of the situation plays an important role in responsiveness to alcohol. Peer-directed social activity of adolescent rats may be a valuable experimental model for the study of ethanol-induced changes in social behavior and assessment of the role of the social context in responsiveness to ethanol. Method: In the present study we used a modified dyad social interaction test to characterize acute effects of ethanol on different forms of social behavior (social investigation, contact behavior, and play) and social motivation (preference/avoidance of a peer) in adolescent rats. Ethanol effects on behavior directed toward a peer were compared with those induced by exposure to an inanimate novel object. Results: In the social context, the effects of ethanol were dose-dependent and biphasic. Low doses of ethanol (0.25,0.75 g/kg) produced apparent social facilitation (increased social activity and enhanced social preference), whereas higher doses (3 and 4 g/kg) caused social inhibition (decreased social activity and avoidance of a peer). This pattern was not observed for a nonsocial stimulus: Although overall activity in the nonsocial context was suppressed by 2 and 3 g/kg of ethanol, 0.5 g/kg of ethanol did not activate overall activity directed to the inanimate object. Conclusions: These findings demonstrate that the social nature of the testing situation plays an important role in responsiveness to alcohol in adolescence, especially to its activating effects. The results suggest also that the study of ethanol effects on social behavior of adolescent rats may be an effective tool for the study of adolescent alcohol use and abuse. [source] Fluvoxamine and sleep disturbances in posttraumatic stress disorderJOURNAL OF TRAUMATIC STRESS, Issue 3 2001Thomas C. Neylan Abstract This study assesses the efficacy of fluvoxamine treatment on different domains of subjective sleep quality in Vietnam combat veterans with chronic posttraumatic stress disorder (PTSD). Medically healthy male Vietnam theater combat veterans (N = 21) completed a 10-week open label trial. Fluvoxamine treatment led to improvements in PTSD symptoms and all domains of subjective sleep quality. The largest effect was for dreams linked to the traumatic experience in combat. In contrast, generic unpleasant dreams showed only a modest response to treatment. Sleep maintenance insomnia and the item "troubled sleep" showed a large treatment response, whereas sleep onset insomnia improved less substantially. These therapeutic benefits contrast with published reports that have found activating effects of Selective Serotonin Reuptake Inhibitors on the sleep electroencephalogram. [source] | ||||||||||