When Thoughts Are in a Race: Area 10 and Bipolar Disorders

Racing thought, when patients incessantly shift from one word or sentence to another while pending previous ones unfinished, is a symptom of (hypo)mania in bipolar disorders received less attention hitherto. Here, based on few evidence, we aim to unfold our hypothetical viewpoint that the frontopolar cortex that is believed to play a part in multitasking and management of competing goals might be dysfunctional in bipolar patients and may contribute in induction of flight of ideas. We then address new avenues for future research and try to encourage researchers to design more comprehensive studies to either accept or decline this proposed conjecture.

Possible role of the hyperpolarization-activated cyclic nucleotide-gated channels in memory consolidation during slow-wave sleep

Over more than a century of research has demonstrated that sleep is necessary for the retention of memory. The current review aim to discuss the functional brain network connectivity is important during slow-wave sleep [SWS] for memory consolidation. While several evidences indicated the importance of SWS for memory consolidation but information to understand the main mechanisms of it are not enough. Although there is the likely involvement of various factors in this phenomenon, we hypothesize the key role of Ih current arising memory consolidation during SWS by generation of neuronal oscillations. Finding the possible mechanism involving in this process may provide lights to suggesting new treatments against memory impairments

Effect of low frequency electrical stimulation of dentate gyrus on amygdala kindling_acquisition in rats

Background: Low frequency stimulation [LFS] has been recently suggested as an antiepileptic method in treating the drugresistant epileptic syndromes such as temporal lobe epilepsy. So far, in the most clinical and experimental studies, LFS has been applied to the seizure focus itself. Considering the role of dentate gyrus in spreading of the limbic seizures, in the present study the effect of LFS of dentate gyrus on amygdala kindling-induced seizures was investigated

Materials and methods: To kindle the animals, using stereotaxic instrument, a tripolar electrode was inserted into right basolateral area of amygdala and a bipolar electrode was ipsilaterally placed in dentate gyrus of male Wistar rats. After a 10 days recovery period, animals divided into two groups. The animals of kindled group were received daily electrical stimulations. In kindled+LFS group, LFS was delivered to dentate gyrus 1 min after cessation of amygdala kindling stimulation. The maximum seizure stage and duration of afterdischarges were evaluated after kindling stimulation. The effect of LFS on behavioral seizure stages and afterdischarges was compared using Kruskall Wallis and repeated measures 2-way AVOVA. A P value less than 0.05 was considered as significant level

Results: The required time to achieve a stage 5 seizure was 12 days in kindled group animals. However, animals of kindled+LFS group did not show more than stage 2 seizure following 12 days of stimulation. LFS of dentate gyrus significantly prevented the increment of behavioral seizure stages and afterdischarge duration in kindled-LFS group compared with kindled group

Conclusion: The results of this study demonstrated that application of LFS in the dentate gyrus can be an effective therapeutic method for controlling the amygdala kindling-induced seizures. Furthermore, this study provide further evidences showing LFS of brain areas involved in spreading the seizures, other than seizure focus can have anticonvulsant affect

Antinociceptive effect of aqueous extract of Origanum vulgare L. in male rats: possible involvement of the GABAergic system

The objective of the present investigation was to assess the possible involvement of GABAergic mechanism in analgesic effect of aqueous extract of Origanum Vulgare [ORG] in a rat model of acute pain test. Sixty-three anaesthetized male Wistar rats [200-250 g] were cannulated into the left ventricle. Five to seven days after the recovery from surgery, ORG extract was intraventricularly injected at dose of 3 ?g/rat i.c.v. Then, baclofen [10 mg/Kg, IP], CGP35348 [100 nmol/Kg, i.c.v], muscimol [1 mg/Kg IP] and bicuculline [5 mg/Kg IP] were separately injected 20 min before the injection of ORG. The experimental groups were compared with intact [control] group [n = 7]. The response latency of rats to thermal stimulation was recorded using Tail-Flick test. Injection of ORG extract resulted in a significant and dose-dependent increase in the response latency. There was also a significant increase in the response latency after co-administration of ORG extract with baclofen when compared with control group. However, following co-administration of ORG extract/bicuculline, a significant decrease in the response latency was observed compared to control group. In conclusion, the results of the present study suggest that aqueous extract of Origanum vulgare L. ssp. viridis possesses antinociceptive activity in a dose-dependent manner and ORG-induced antinociception might be mediated, at least in part, by both GABA receptors

Evaluation of Origanum vulgare L. ssp. viridis leaves extract effect on discrimination learning and LTP induction in the CA1 region of the rat hippocampus

The objective of this study was to determine the effect of aqueous extract of Origanum vulgare L. ssp. Viridis [ORG] on discrimination learning and long term potentiation [LTP] in CA1 region of the rat hippocampus. A group of adult male Wistar rats weighing 275 +/- 25 g received aqueous extract of ORG [150, 300, 450 mg/kg/day] by intraperitoenal injection for one week, and the other group received saline [n=6]. A wooden T-maze was used to evaluate the discrimination learning. In electrophysiological experiments, the effects of ORG leaves extract on induction and maintenance long term potentiation [LTP] in CA1 hippocampus area was determined. LTP was evaluated in CA1 region after high-frequency stimulation [200 Hz] of the Schaffer collaterals. Also, serum antioxidant levels were analyzed in the two groups [n=4]. Statistical analysis showed significant decreases in the number of total [significantly at the dose of 300 and 450 mg/kg] and wrong [significantly at the dose of 300 mg/kg] entrance into opposite box of T-maze procedure in ORG-treated animals [P<0.05]. In electrophysiological study, the rats which had received ORG [150, 300, and 450 mg/kg] showed an increase in both population spike amplitude [59.7 +/- 14.1%, 85 +/- 14.7% and 49.3 +/- 8.7% respectively, compared to 39 +/- 9.2% increase in saline group] and maintenance of LTP in hippocampus CA1 after high frequency stimulation in Schaffer collateral pathway. In serum antioxidant assay, level of antioxidants in ORG groups [300 and 450 mg/kg] remarkably increased in comparison to saline group [P< 0.05 and P<0.001, in turn]. Our result suggest that Origanum aqueous extract can improve the learning criteria in rats

intracerebroventricular [ICV] administration of w-7, a calmodulin inhibitor, attenuates the development of morphine tolerance in rats

The present study was performed to determine the effect of intracerebroventricular [ICV] administration of W- 7, a specific calmodulin inhibitor, on the development of tolerance to antinociceptive effect morphine administration. This study was carried out on male wistar rats, weighing 200-250 g. Morphine was administered daily [15 mg/kg for 8 days]. The threshold to thermal nociceptive stimuli was measured by tail-flick test. W-7 [0.25, 0.5 and 1 micro mol/rat] was injected through ICV. Maximal possible effect percentage [MPE%] was considered as analgesia index. Our result showed that chronic morphine exposure induced tolerance to its antinociceptive effect and administration of W-7 [0.5 and 1 micro mol/rat] decreased the development of tolerance to it. In conclusion these data showed that chronic injection of W-7 inhibited the development of morphine tolerance which indicates that calmodulin and its dependent pathways may play a role in the morphine tolerance processes

[Differences of intensities regarding withdrawal signs in experimental methods for inducing morphine dependency]

In the present study, we compared the intensity of physical dependency, mortality rate and weight changes in some common methods for inducing morphine dependency. Six common different methods for morphine dependency were chosen in wistar rats. In all methods, morphine dependency was induced by repeated morphine injection. Precipitation of morphine withdrawal signs were performed on the last day in each method, 4 hours after the last morphine injection for 20 minutes. The withdrawal signs included: vertical jumping, wet dog shakes, diarrhea, teeth chattering, ptosis, head shakes and rearing. Our results demonstrated that all groups of treated rats showed withdrawal signs following naloxone challenge. However, the intensities of withdrawal signs [vertical jumping, wet dog shakes, diarrhea, teeth chattering, head shakes and rearing] were significantly different among these methods. Also, mortality rate and amount of weight loss were significantly different among the different methods. This study demonstrates that different experimental methods of morphine dependency can induce different intensities of withdrawal signs, mortality rate and weight loss