Effects of melatonin on behavioral changes of neonatal rats in a model of cortical dysplasia.

BACKGROUND: Cortical dysplasia (CD) is associated with several behavioral disorders in both the pediatric and the adult population. The effect of melatonin on behavioral disorders in rats generated CD has not been investigated so far. AIM: To investigate the effects of melatonin administration on activity and anxietic behavior of neonatal rats in a model of CD. MATERIALS AND METHODS: Newborn Sprague-Dawley rats (n=21) were randomized into three groups. On postnatal day 1, one freeze lesion was carried out in 14 rats between bregma and lambda to create a CD model. Another group of neonatal rats served as control group (n=7). Those 14 rats were either administered melatonin (n=7) or vehicle solution (n=7). Melatonin treatment (4 mg/kg/day, i.p.) was initiated ten days after induction of cold injury and continued for three weeks. Animal activity and anxiety were analyzed by using open field and elevated plus maze tests 24h after the last melatonin administration (day 32) in a blind manner. RESULTS: It was observed that CD induced animals spent significantly less time in the open field area when compared to the other groups (p < 0.01). Additionally, the time spent in the open field area was significantly elevated in the melatonin-treated animals compared to both the control and the CD groups (p < 0.01). Accordingly, anxiety scores in the CD group was significantly increased (p < 0.01), and this effect could be reversed by administration of melatonin. CONCLUSIONS: Melatonin exerts protective behavioral effects against cortical dysplasia in newborn rats. Further clinical investigations may prove melatonin as a useful therapeutic adjunct to prevent from possible behavioural damages of cortical dysplasia.

RLIP76 Gene Variants are not Associated with Drug Response in Turkish Epilepsy Patients.

Approximately 30% of epileptic patients remain untreated, in spite of trials with maximum tolerable doses of more than one drug. The RalA binding protein 1 (RALBP1/RLIP76), a multifunctional, anti-apoptot-ic, multidrug transporter protein, has been proposed as being responsible for the drug resistance mechanism in epilepsy. We have investigated polymorphic differences in the coding regions and exonintron boundaries of the RLIP76 gene, between 146 refractory and 155 non refractory epileptic patients in Turkey, using denaturing high performance liquid chromatography (HPLC) and sequencing analysis techniques. We have detected the following sequence variants: c.160-4G>A, c.187C>G, c.1562-38G>A, c.1670+107G>A, c.1670+93G>A, c.1670+96G>A, c.1670+100C>T, c.1670+130C>T, c.1670+131G>C, c.1670+140 G>C, and found no statistically significant correlation between allele frequencies and drug response status. We conclude that sequence variants of this gene are not involved in drug resistance in epilepsy.

The effect of one year's swimming exercise on oxidant stress and antioxidant capacity in aged rats.

The effect of exercise on oxidant stress and on alterations in antioxidant defense in elderly has been investigated extensively. However, the impact of regularly performed long-term physical activity starting from adulthood and prolonged up to the old age is not yet clear. We have investigated the changes in the activities of antioxidant enzymes - superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) - and lipid peroxidation in various tissues of rats which had performed (old-trained) or had not performed (old-control) regular swimming exercise for one year. These animals were compared with young-sedentary rats. Increased lipid peroxidation was observed with ageing in all tissues (heart, liver, kidney, striated muscle) and swimming had no additional effect on this elevation of lipid peroxidation. Heart and striated muscle SOD activites, and striated muscle CAT activity increased as a consequence of ageing, whereas kidney and liver CAT activities, as well as GPx activities in kidney, liver, lung and heart were significantly decreased compared to young controls. Lung and heart SOD, liver CAT activities as well as GPx activities in liver, lung and heart were increased significantly in rats which performed exercise during ageing, compared to the old-control group. These findings suggest that lifelong exercise can improve the antioxidant defense in many tissues without constituting any additional oxidant stress.

Recovery cycle of the blink reflex and exteroceptive suppression of temporalis muscle activity in migraine and tension-type headache.

Brain stem interneuronal excitability can be assessed by recording the recovery cycle of the blink reflex and exteroceptive suppression of temporalis muscle activity. Abnormal endogenous pain control mechanisms due to disturbed brain stem interneuronal activity have been implicated in the pathogenesis of tension-type headaches. The blink reflex, exteroceptive suppression of temporalis muscle activity, and the recovery curve of both the R2 component of the blink reflex and the ES2 component of the exteroceptive suppression of the temporalis muscle activity were studied in 20 patients with migraine without aura, 32 patients with tension-type headache, and 20 normal controls. In our study, the blink reflex was elicited by stimulation of the supraorbital nerve; the exteroceptive suppression of the temporalis muscle activity was elicited by applying electrical shocks to the labial commissure, both on the lower and upper sides. The recovery cycle was established by delivering paired shocks at different interstimulus intervals. Comparisons were made between normal control subjects, patients with migraine without aura, and patients with tension-type headache. The latency of R1, R2, and R2', the amplitude and size of the R2 and R2' components of the blink reflex, the latency and duration of the ES1 and ES2 components, and the recovery curve of the ES2 component of the temporalis muscle activity did not differ between groups. However, the recovery curve of the R2 component of the blink reflex diminished in patients with tension-type headache compared with the other groups. Our findings indicate reduced excitability of the brain stem interneurons in patients with tension-type headache.

Dizygotic twins with schizencephaly and focal cortical dysplasia.

The case reports of 17-year-old female dizygotic twins are presented. One of the twins had bilateral closed-lip schizencephaly, and the other had focal cortical dysplasia. Septum pellucidum was absent in both cases. The cortical dysplasia in case 2 corresponded to the same hemispheric location with the right schizencephalic cleft in case 1. The combination of schizencephaly and focal cortical dysplasia in siblings or twins has not been previously reported.

The effect of sulfur dioxide inhalation on visual evoked potentials, antioxidant status, and lipid peroxidation in alloxan-induced diabetic rats.

The aim of the study was to investigate the effect of 10 ppm sulfur dioxide (SO(2)) exposure on visual evoked potentials (VEPs), thiobarbituric acid reactive substances (TBARS), and the activities of Cu,Zn superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) in diabetes mellitus. Forty healthy male albino rats, aged 3 months, were divided into four equal groups: control (C), sulfur dioxide + control (CSO(2)), diabetic (D), and sulfur dioxide + diabetic (DSO(2)) groups. Experimental diabetes mellitus was induced by IV injection of alloxane monohydrate in a dose of 50 mg/kg body weight. Ten ppm sulfur dioxide was administered to the animals of sulfur dioxide-exposed groups in an exposure chamber for 1 h/day x 7 days/week x 6 weeks while control and diabetic groups were exposed to filtered air in the same condition. SO(2) exposure, though markedly decreasing retina CAT and GSH-Px activities, significantly increased retina Cu,Zn-SOD activity in the diabetic and nondiabetic groups. In contrast to SO(2)-related increase in the activity of Cu,Zn-SOD, decrease in GSH-Px activity was observed in the brain of those groups. Brain CAT activity was unaltered. SO(2) exposure caused the significant elevation in brain TBARS levels of CSO(2) and DSO(2) groups, whereas only in the retina TBARS level of the CSO(2) group. SO(2) exposure caused the significant prolongations of P(1), N(1), P(2), and P(3) components of VEPs in the nondiabetic and all components of VEPs in the diabetic groups. SO(2) exposure also resulted in significant amplitude reductions in both experimental groups.

The effect of cadmium and experimental diabetes on EEG spectral data.

Fifty-two healthy male Swiss albino rats, aged three months, were used in this study. They were divided into four groups: control (C), diabetic (D), cadmium (Cd) and diabetic + Cd (D + Cd). Diabetes was induced in the D and D + Cd groups by administration of alloxane (5 mg/100 g). After this treatment, the Cd and D + Cd groups were injected with CdCl2 i.p. (2 mg/kg/week). At the end of the two month experimental period, EEGs of the four groups were recorded and amplitude spectral analysis was computed by Fast Fourier Transform (FFT) algorithm. Significant amplitude (dB) increment was observed in 16-30 Hz of Cd group compared with C and D groups. Significant amplitude decrement was found in the 2-4 Hz frequency band of the D + Cd group compared with C, Cd and D groups.

The effect of pre and postnatal cadmium exposure on somatosensory evoked potentials: relation to lipid peroxidation.

Pregnant swiss albino rats were divided into three groups: control (C), gestational exposure of cadmium (G-Cd) and gestational/postnatal exposure of cadmium (GP-Cd) groups. Control animals received tap water and the rats of GP-Cd group received Cd as CdCl2 in their drinking water during the experimental period. G-Cd group was given Cd during pregnancy, but given tap water after birth. Twenty-two days after birth, 15 rats (for each group) were taken from their mothers and continued to be treated with Cd (GP-Cd group) or tap water (C and G-Cd groups) for an additional 38 days. On postnatal day (PND) 60, somatosensory evoked potentials (SEPS) of three groups were recorded following left posterior tibial nerve (PTN) stimulation. The mean latencies of N1, P1, and N2, components were significantly prolonged in both Cd groups compared with control group. The mean latency of N1 in the GP-Cd group was longer than control and the G-Cd groups. There was no significant amplitude differences among groups. On the other hand, thiobarbituric acid reactive substances (TBARS), an indicator of lipid peroxidation, were increased in the sciatic nerves of both groups compared with control group. A significant increase in the TBARS level of the brain was found only in GP-Cd group due to significant accumulation of Cd.

Effect of long-term swimming exercise on somatosensory evoked potentials in rats.

The study investigated whether long-term swimming exercise prevents age-related changes in rat somatosensory evoked potentials (SEPs) and somatosensory cortex (SC) morphology. A total of 25 9-month-old rats were assigned to an exercise or control group. The exercise group swam 1 h/day five times weekly for 1 year. The results showed that long-term exercise prevented age-related changes in SEPs and SC morphology.