The influence of stereotaxic lesions of claustrum on motor movements and behaviour in rats.

BACKGROUND: This study aimed to expand our existing information on changes in the regulation of motor movement and behaviour by investigating the effects of unilateral and bilateral lesions on the claustrum (CL). MATERIAL AND METHODS: 36 Wistar Albino adult male rats were randomly divided into six groups. An electrical lesion was created with a constant current source in the unilateral and bilateral anterior clastrum using a stereotaxic frame in rats. The lesioned groups and the control group underwent an automatic behaviour recording device such as mobilisation, freezing, eating, drinking behaviour, grooming, turning, etc. behaviour was recorded and analysed. Simultaneously, ultrasonic sounds in rats were examined with ultrasonic sound recording program. Anxiety was then reassessed with the elevated plus maze test. Data were compared with the control group. Rats were eventually sacrificed and the brain tissue was post-fixed. Histochemical examination was done and lesions' existence was confirmed. RESULTS: In this study, lesions of ventral of CL can cause increase in spontaneous behaviours such as freezing and rearing. And, it has been shown to cause a statistically significant change. In addition to the behavioural changes, right CL lesions have caused a significant increase in drinking behaviour associated with increased anxiety. All operated groups showed a significant decrease in clockwise and counterclockwise rotation movements. CONCLUSION: Experimental results show that CL lesions influence spontaneous behaviour which indicate the need for new studies to understand the role of CL in anxiety-depression.

Effect of gabapentin on sleep-deprivation-induced disruption of prepulse inhibition.

RATIONALE: There are controversial reports on the effects of gabapentin in respect to psychotic symptoms. Prepulse inhibition of the acoustic startle response is an operational measure of sensorimotor gating. In laboratory rodents, deficits in sensorimotor gating are used to model behavioral endophenotypes of schizophrenia. Sleep deprivation disrupts prepulse inhibition and can be used as a psychosis model to evaluate effects of gabapentin. OBJECTIVES: This study aimed to investigate behavioral effects of gabapentin in both naïve and sleep-deprived rats. METHODS: Sleep deprivation was induced in male Wistar rats by using the modified multiple platform technique in a water tank for 72 h. The effect of water tank itself was studied in a sham group. The effects of oral acute and subchronic (4.5 days) gabapentin doses (25, 100, or 200 mg/kg/day) on sensorimotor gating and locomotor activity was evaluated by prepulse inhibition test and locomotor activity test, respectively. Plasma gabapentin levels of some groups and body weights of all groups were also assessed. RESULTS: Sleep deprivation disrupted prepulse inhibition, increased locomotor activity, reduced gabapentin plasma levels, and body weights. Some gabapentin doses disrupted sensorimotor gating irrespective of sleep condition. Some gabapentin doses increased locomotor activity in non-sleep-deprived rats and decreased locomotor activity in sleep-deprived rats. On the contrary, gabapentin did not normalize sleep deprivation-induced disruption in sensorimotor gating. CONCLUSIONS: Sleep deprivation via modified multiple platform technique could be used as an animal model for psychosis. Gabapentin may have dose- and duration-dependent effects on sensorimotor gating and locomotor activity.

Behavioural and neurobiological consequences of 2 different chronic stressors in rats.

BACKGROUND/AIM: To compare the behavioural and neurobiological consequences of chronic headache and chronic mild stress (CMS) in rats. MATERIALS AND METHODS: Forty-eight male Wistar rats were divided into 4 groups: 1) control group, 2) chronic headache group, 3) CMS group, and 4) sham group. Their behaviour prior to (D0) and after (D14) chronic stress was analysed. Afterwards, they were exposed to the Elevated Plus Maze (EPM) in order to evaluate anxiety-like behaviour and the Forced Swim Test (FST) for observation of depressive-like behaviour. Ultrasonic vocalisations (USVs) were recorded by a USV detector system at DO and D14 and during the FST. The c-fos expressions in various brain regions were analysed 2 h after the EPM and FST. RESULTS: The control group showed significantly more sleeping behaviour at D14 (χ2 = 8.213, P = 0.042), emitted more negative and positive affect USVs at D14 (χ2 = 9.853, P = 0.020) and during FST (χ2 = 4.000, P = 0.046) than the chronic headache and CMS groups, and showed significantly less anxiety-like behaviour in the EPM than the CMS group (P = 0.021). CONCLUSION: These results suggest that CMS increases anxiety-like behaviour but not depressive-like behaviour, while chronic headache does not have a significant effect on these behaviours in rats.