Biomedical subjects

Maytal Shabat-Simon

Publications and source records attributed to Maytal Shabat-Simon.

3 recordsLinked to original sources

PubMed2006

Chronic exposure to Delta9-tetrahydrocannabinol downregulates oxytocin and oxytocin-associated neurophysin in specific brain areas.

Cannabinoids are widely abused drugs. Our goal was to identify genes modulated by Delta9-tetrahydrocannabinol (Delta9-THC) treatment. We found that chronic administration of Delta9-THC (1.5 mg/kg/day, i.p.; 7 days) to rats, downregulates the expression of oxytocin-neurophysin (OT-NP) mRNA and of OT and oxytocin-associated NP (NPOT) immunoreactivity in nucleus accumbens (NAc) and ventral tegmental area (VTA), brain areas involved in reward and addiction. Real-time PCR revealed a 60% and 53% reduction of OT-NP mRNA in NAc and VTA, respectively, under chronic treatment, while no changes were observed in NAc after 24 h. Immunohistochemistry showed a large decrease in number of OT and NPOT-stained fibers in NAc (by 59% and 52%, respectively) and VTA (by 50% and 56%, respectively). No changes in cell staining were observed in the paraventricular nucleus and supraoptic nucleus. As OT is known to inhibit development of drug tolerance and attenuate withdrawal symptoms, we suggest that OT downregulation could play a role during the establishment of the chronic effects of Delta9-THC.

Animals↗

PubMed2005

Dehydroepiandrosterone (DHEA) attenuates cocaine-seeking behavior in the self-administration model in rats.

The aim of this study was to determine the possible involvement of the neurosteroid dehydroepiandrosterone (DHEA) in cocaine-seeking behavior in a self-administration model in rats. DHEA pretreatment (continued thereafter concomitantly with cocaine self-administration) attenuated cocaine-seeking behavior and elevated the levels of dopamine and serotonin in several brain regions relevant to cocaine addiction. Chronic cocaine self-administration induced elevation in brain DHEA, its sulfate ester, DHEAS, and pregnenolone. The increased brain DHEA following cocaine self-administration may serve as a compensatory protective mechanism geared to attenuate the craving for cocaine. Such anti-craving activity is further enhanced by DHEA treatment before and during cocaine self-administration.

Affect↗

PubMed2004

Behavioral analysis during the forced swimming test using a joystick device.

The behavioral test described by Porsolt in 1977 for screening potential antidepressant drugs is extensively used both in basic research and in the pharmaceutical industry. The measured behavior is the immobility time during the swimming test (preformed in rodents), which decreases upon acute antidepressant treatment. Several research groups have suggested some modifications on the original Porsolt paradigm and its analysis. Nevertheless, there are still inaccuracies resulting from either undefined intermediate behaviors or from considering the movement of the whole body as one unit without analyzing the motion of the limbs. Herein, we propose a novel and simple scoring method, based on continuous measurement of the limbs motion, using a joystick, a computer screen and simple software. We validated the method, using antidepressant drugs and studied examples of false positives and false negatives of the traditional Porsolt paradigm. The proposed method is easy to use, it accounts for all range of movements and the analysis is relatively fast. Moreover, the results obtained using this analysis method show a normal Gaussian distribution in a population of rats (while the traditional Porsolt analysis does not) which allows selective breeding of 'motivated' and 'depressed' lines of animals.

Animals↗