Melatonin is protective against 6-hydroxydopamine-induced oxidative stress in a hemiparkinsonian rat model.

Melatonin is known to reduce detrimental effects of free radicals by stimulating antioxidant enzymes; however, its role has not been studied in 6-hydroxydopamine (6-OHDA)-induced rat model of Parkinson's disease (PD). Therefore, we aimed to elucidate the effects of melatonin on motor activity and oxidative stress parameters in 6-OHDA-induced rat model of PD. Three-month-old male Wistar rats were divided into 5 groups: vehicle (V), melatonin-treated (M), 6-OHDA-injected (6-OHDA), 6-OHDA-injected + melatonin-treated (6-OHDA-Mel), and melatonin-treated + 6-OHDA-injected (Mel-6-OHDA) group. Melatonin was administered intraperitoneally at a dose of 10 mg/kg/day for 30 days in M and Mel-6-OHDA groups, for 7 days in 6-OHDA-Mel group. Rats received a unilateral stereotaxic injection of 6-OHDA into the right medial forebrain bundle. The 6-OHDA-Mel group started receiving melatonin when experimental PD was created and the treatment was continued for 7 days. In the Mel-6-OHDA group, experimental PD was created on the 23rd day of melatonin treatment and continued for the remaining 7 days. Locomotor activity decreased in 6-OHDA group compared with that in vehicle group; however, melatonin treatment did not improve this impairment. 6-OHDA injection caused an obvious reduction in tyrosine-hydroxylase-positive dopaminergic neuron viability as determined by immunohistochemistry. Melatonin supplementation decreased dopaminergic neuron death in 6-OHDA-Mel and Mel-6-OHDA groups compared with that in 6-OHDA group. Biochemical analysis confirmed the beneficial effects of melatonin displaying higher superoxide dismutase, catalase, and glutathione peroxidase activities and lower lipid peroxidation in substantia nigra samples in comparison to non-treated 6-OHDA group. Starting melatonin treatment before creating experimental PD was more effective on observed changes.

Effects of extremely low-frequency electric fields at different intensities and exposure durations on mismatch negativity.

The effects of extremely low-frequency electric fields (ELF-EFs, 3-300Hz) on lipid peroxidation levels and antioxidant enzyme activities have been shown in many tissues and plasma after exposure to 50-Hz alternating current (AC) electric fields. However, similar studies investigating brain lipid peroxidation status are limited. Moreover and as far as we know, no study has been conducted to examine mismatch negativity (MMN) response in rats following exposure to a 50-Hz AC electric field. Therefore, the purpose of the study was to investigate different intensities and exposure durations of ELF-EFs on MMN component of event-related potentials (ERPs) as well as apoptosis and oxidative brain damage in rats. Ninety male rats, aged 3months were used in our study. A total of six groups, composed of 15 animals each, was formed as follows: sham-exposed rats for 2weeks (C2), sham-exposed rats for 4weeks (C4), rats exposed to 12-kV/m and 18-kV/m electric fields for 2weeks (E12-2 and E18-2), rats exposed to 12- and 18-kV/m electric fields for 4weeks (E12-4 and E18-4). At the end of the experimental period, MMN responses were recorded in urethane-anesthetized rats by electrodes positioned stereotaxically to the surface of the dura. After MMN recordings, animals were killed by exsanguination and their brain tissues were removed for 4-hydroxy-2-nonenal (4-HNE), protein carbonyl and TUNEL analysis. In the current study, different change patterns in ERP parameters were observed dependent on the intensity and exposure duration of ELF-EFs. There were differences in the amplitudes of ERP between the responses to the standard and the deviant tones in all groups. When peak-to-peak amplitude of the difference curves was evaluated, MMN amplitude was significantly decreased in the E18-4 group compared with the C4 group. Additionally, the amount of 4-HNE was increased in all experimental groups compared with the control group. Consequently, it could be concluded that electric field decreased MMN amplitudes possibly induced by lipid peroxidation.

The effect of lipoic acid on antioxidant status and lipid peroxidation in rats exposed to chronic restraint stress.

This study was designed to investigate effect of alpha-lipoic acid (LA) on lipid peroxidation, nitric oxide production and antioxidant systems in rats exposed to chronic restraint stress. Twenty four male Wistar rats, aged three months, were divided into four groups: control (C), the group treated with LA (L), the group exposed to restraint stress (S) and the group exposed to stress and treated with LA (LS). Restraint stress was applied for 21 days (1 h/day) and LA (100 mg/kg/day) was injected intraperitonally to the L and LS groups for the same period. Restraint stress significantly decreased brain copper/zinc superoxide dismutase (Cu,Zn-SOD) and brain and retina glutathione peroxidase (GSH-Px) and catalase (CAT) activities compared with the control group. Thiobarbituric acid reactive substances (TBARS), nitrite and nitrate levels were significantly increased in the tissues of the S group compared with the C group. LA produced a significant decrease in brain and retina TBARS, nitrite and nitrate levels of the L and LS groups compared to their corresponding control groups. LA increased all enzyme activities in the tissues of the LS group compared to the S group. Our study indicated that LA is an ideal antioxidant candidate for the prevention of stress-induced lipid peroxidation.

Model-based color halftoning using direct binary search.

In this paper, we develop a model-based color halftoning method using the direct binary search (DBS) algorithm. Our method strives to minimize the perceived error between the continuous tone original color image and the color halftone image. We exploit the differences in how the human viewers respond to luminance and chrominance information and use the total squared error in a luminance/chrominance based space as our metric. Starting with an initial halftone, we minimize this error metric using the DBS algorithm. Our method also incorporates a measurement based color printer dot interaction model to prevent the artifacts due to dot overlap and to improve color texture quality. We calibrate our halftoning algorithm to ensure accurate colorant distributions in resulting halftones. We present the color halftones which demonstrate the efficacy of our method.

Effects of N-nitro l-arginine methyl ester (l-NAME), a potent nitric oxide synthase inhibitor, on visual evoked potentials of rats exposed to different experimental stress models.

AIM: The aim of our study was to investigate the effects of the nitric oxide synthase inhibitor, N-nitro l-arginine methyl ester (l-NAME, 10 mg kg-1 day-1 i.p.), on visual evoked potentials (VEPs) and lipid peroxidation expected to occur during chronic stress (15 days). METHODS: Eight experimental groups, each consisting of 10 rats, were formed: control group (C), the group injected with l-NAME (L), groups exposed to cold stress (CS), immobilization stress (IS), and both cold and immobilization stress (CIS), groups exposed to stress and injected with l-NAME (CSL, ISL, CISL). RESULTS: l-NAME decreased brain and retina nitrite levels in all experimental groups compared with their corresponding control groups. l-NAME decreased glutathione peroxidase (GSH-Px) activity in the brain and retina in the L group, but increased it in the CSL and CISL groups compared with the C group. Lipid peroxidation was increased in the brain and retina tissues of all stress groups with respect to the C group. l-NAME markedly increased brain thiobarbituric acid reactive substances (TBARS) levels in the L group, while significantly decreasing brain and retina TBARS levels in all stress groups in comparison with their respective control groups. l-NAME caused a significant delay in all components of VEPs in the L group compared with the C group. However, l-NAME significantly decreased latencies of P1, N1, P2 and P3 components in the CSL group and all components in the ISL and CISL groups with respect to their corresponding control groups. CONCLUSION: This study clearly indicated that lipid peroxidation may be one possible factor affecting VEP components.

Marked changes in erythrocyte antioxidants and lipid peroxidation levels of rats exposed to acute, repeated and chronic restraint stress.

The aim of this study was to investigate the effects of acute, repeated and chronic restraint stress on the antioxidant status and lipid peroxidation. For this purpose, 48 male Wistar rats, aged three months were used in this study. Rats were separated into six groups as follows; control (C), acute stress (AS), restrained for 7 days (1 h/day) (RS), restrained for 21 days (1 h/day) (CS1), restrained for 28 days (1 h/day) (CS2) and restrained for 21 days (1 h/day) and allowed to recovery for 7 days (CS3). Copper, zinc-superoxide dismutase (Cu, Zn-SOD), catalase (CAT) and selenium-dependent glutathione peroxidase (Se-GSH-Px) activities, corticosterone, reduced glutathione (GSH) and thiobarbituric acid-reactive substances (TBARS) levels were measured in blood samples. Corticosterone levels of all groups were found to be elevated after stress compared to group C. Cu, Zn-SOD activity was lower in all stress groups than in group C. CAT and Se-GSH-Px activities were increased in all stress groups. All stress models decreased GSH levels except for the CS3 group. TBARS levels were higher in stress groups than in C group except for AS group. The highest corticosterone level, CAT and Se-GSH-Px activity and TBARS level were seen in group RS. The lowest Cu, Zn-SOD activity and GSH level were seen in group CS2. These results may have an important implication for impaired erythrocyte antioxidant enzyme activities and glutathione levels resulting from exposure to different stress models (acute, repeated and chronic restraint stress).

Training induced alterations of visual evoked potentials are not related to body temperature.

The purpose of this study was to investigate the effect of mild chronic exercise on visual evoked potentials (VEPs). Twenty male Wistar rats were randomly divided into two groups: Control (C) and Exercise (E) groups. Exercise was performed on a motor-driven treadmill for 8 weeks. After 5 min of exercise, plasma lactic acid levels were determined. At the end of the experimental period, VEPs were recorded from E group twice: Five min (E-5 min) and 24 h (E-24 h) after the last bout of exercise. During visual evoked potential (VEP) recordings body temperature of the animals was kept constant to eliminate the effect of temperature changes. No difference was found between the lactic acid levels of two groups. The mean latencies of VEPs from E-5 min were shortened compared with the control group. The mean latencies of VEP components in E-24 h were observed to have returned to the control levels. Peak to peak amplitudes of VEPs were found to be unaltered among all measurements. We concluded that immediately after exercise, VEPs latencies were shortened independently from body temperature via unknown mechanisms. The latencies of VEPs were returned to control values after 24 h.

The effect of exercise on brain antioxidant status of diabetic rats.

BACKGROUND: To investigate the effect of exercise on brain antioxidant status of diabetic rats. METHODS: Wistar rats were divided into four groups: Control (C), exercise (CE), diabetic (D), and diabetic+exercise (DE). Diabetes was induced by single administration of streptozotocin (60 mg/kg). We used an aerobic exercise program for 8 weeks of CE and DE rats. After the end of the experimental period, Cu, Zn-superoxide dismutase (Cu, Zn-SOD), catalase (CAT), glutathione peroxidase (GSH-Px), xanthine dehydrogenase (XDH) and xanthine oxidase (XO) activities and thiobarbituric acid reactive substances (TBARS) levels of brain were measured. RESULTS: Diabetes caused significant reduction of brain Cu, Zn-SOD and GSH-Px activities in the D and DE groups. CAT activity was decreased only in the D group. Exercise did not alter CAT activity of brain, whereas markedly increased Cu, Zn-SOD activity in the DE group. In contrast to diabetes-related decrease in the activity of Cu, Zn-SOD, increase in the XO and GSH-Px activities were observed in the DE group compared with the D group. XDH activity was significantly reduced in two exercise groups according to the control rats, but the decrease was not accompanied with the activity of XO elevation in all groups. Increase in the XO activity and decrease in the XDH activity in the DE rats have revealed that diabetes and exercise have potentially effect in free radical production. On the other hand, TBARS levels were found to be elevated in all diabetic animals. CONCLUSIONS: Our results show that aerobic exercise did not affect lipid peroxidation of brain, but in diabetic condition improved antioxidant defence.

Identification of Anopheles aquasalis as a possible vector of malaria in Guyana, South America

Adult female mosquitoes were collected in Mahdia, Guyana, to determine the incidence of malaria in Anopheles species found during the month of June 2000. Centers for Disease Control miniature white (incandescent) light traps, model 512, and miniature black (ultraviolet) light traps, model 912, were used to capture female mosquitoes. Numbers of mosquitoes collected were compared between white and black light traps and between traps set outside and inside of buildings. Adult female Anopheles mosquitoes were identified and an ELISA dipstick test for Plasmodium vivax and Plasmodium falciparum was performed on each mosquito. An aquasalis, An oswaldoi, and An braziliensis were attracted to white light traps. An triannulatus and An darlingi were collected from black light traps. Approximately the same numbers of all female Anopheles mosquitoes 28/45 (62) were caught inside buildings as outside. Numbers of female non-anopheles mosquitoes captured in light traps varied between the traps set outside of buildings and inside of buildings with bright light traps collecting 91/122 (75). A total of 45 Anopheles mosquitoes were captured and 122 non-anopheles species. Of the two known vectors of malaria in Guyana, An darlingi mosquitoes were not infected with P vivax but An aquasalis was found to be a carrier. The findings of this study suggest a need for further surveying and identification of current malaria vectors in Guyana.

Age-related changes in antioxidant enzyme activities and lipid peroxidation in lungs of control and sulfur dioxide exposed rats.

Antioxidant defenses within the lung are pivotal in preventing damage from oxidative toxicants. There have also been several reports with conflicting results on the antioxidant system during aging. In this study, we attempted to investigate age-related alterations in both antioxidant enzyme activities and thiobarbituric acid-reactive substances (TBARS), a product of lipid peroxidation, in the whole lung of control and sulfur dioxide (SO2) exposed rats of different age groups (3-, 12-, and 24-months-old). Swiss-Albino Male rats were exposed to 10 ppm. SO2 1 hr/day, 7 days/week for 6 weeks. The antioxidant enzymes examined include Cu,Zn-superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px) and glutathione S-transferase (GST). A mixed pattern of age-associated alterations in antioxidant activities was observed. SOD, GSH-Px and GST activities were increased with age, but CAT activity was decreased. Lung SOD, GSH-Px and GST activities were also increased in response to SO2. The level of TBARS was increased with age. SO2 exposure stimulated lipid peroxide formation in the lung as indicated by an increase in the level of TBARS. These findings suggest that both aging and SO2 exposure may impose an oxidative stress to the body. We conclude that the increase in the activities of the antioxidant enzymes of the lung during aging, could be interpreted as a positive feedback mechanism in response to rising lipid peroxidation.

Effect of sulfur dioxide inhalation on erythrocyte antioxidant status, food intake, and lipid peroxidation during aging.

The effect of sulfur dioxide on red blood cell antioxidant status and lipid peroxidation was investigated in young (3 mo), middle-age (12 mo), and old (24 mo) male albino rats. Ten ppm of sulfur dioxide was administered to the rats in the sulfur dioxide groups in an exposure chamber. Exposure occurred 1 hr/d, 7 d/wk, for 6 wk; control rats were exposed to filtered air during the same time periods. Copper-zinc superoxide dismutase, glutathione peroxidase, catalase, glutathione, and glutathione-S-transferase activities were significantly decreased in the middle-aged and older groups, compared with the young group. Sulfur dioxide exposure significantly decreased copper-zinc superoxide dismutase activity in all experimental groups, compared with controls. Sulfur dioxide exposure significantly increased enzyme and glutathione activities.

Identification of Anopheles aquasalis as a possible vector of malaria in Guyana, South America.

Adult female mosquitoes were collected in Mahdia, Guyana, to determine the incidence of malaria in Anopheles species found during the month of June 2000. Centers for Disease Control miniature white (incandescent) light traps, model 512, and miniature black (ultraviolet) light traps, model 912, were used to capture female mosquitoes. Numbers of mosquitoes collected were compared between white and black light traps and between traps set outside and inside of buildings. Adult female Anopheles mosquitoes were identified and an ELISA dipstick test for Plasmodium vivax and Plasmodium falciparum was performed on each mosquito. An aquasalis, An oswaldoi, and An braziliensis were attracted to white light traps. An triannulatus and An darlingi were collected from black light traps. Approximately the same numbers of all female Anopheles mosquitoes 28/45 (62%) were caught inside buildings as outside. Numbers of female non-anopheles mosquitoes captured in light traps varied between the traps set outside of buildings and inside of buildings with bright light traps collecting 91/122 (75%). A total of 45 Anopheles mosquitoes were captured and 122 non-anopheles species. Of the two known vectors of malaria in Guyana, An darlingi mosquitoes were not infected with P vivax but An aquasalis was found to be a carrier. The findings of this study suggest a need for further surveying and identification of current malaria vectors in Guyana.

Effects of sulfur dioxide inhalation on plasma vitamin C and ceruloplasmin in ageing rats.

Ageing is associated with changes in physical characteristics and decline of many physiological functions. It has been accepted that the oxidative stress or damage induced by free radicals is related to ageing. Three age groups, 3, 12 and 24 months, were used to investigate whether age-associated changes in some parameters (vitamin C and ceruloplasmin) in the plasma of male Swiss-Albino rats and to observe possible effects of sulfur dioxide (SO2) for 6 weeks on the same parameters. Rats were exposed to 10 ppm SO2 1 hr/day, 7 days/week for 6 weeks. Control groups were exposed to filtered air in the same conditions. An effect of SO2 on those parameters was observed. The level of vitamin C and ceruloplasmin in plasma were decreased in young, middle-aged and old groups in response to SO2.

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.

Pressure related apoptosis in neuronal cell lines.

Pressure is a crucial component of the cellular environment, and can lead to pathology if it varies beyond its normal range. The increased intra-ocular pressures in acute glaucoma are associated with the loss of neurons by apoptosis. Little is known regarding the interaction between pressure and apoptosis at the level of the cell. The model developed in this study examines the effects of elevated ambient hydrostatic pressure directly upon cultured neuronal lines. Conditions were selected to be within physiological limits: 100 mmHg over and above atmospheric pressure for a period of 2 hr, as seen clinically in acute glaucoma. This system can be used to investigate pressure relatively independently of other variables. Neuronal cell line cultures (B35 and PC12) were subjected to pressure conditions in specially designed pressure chambers. Controls were treated identically, except for the application of pressure, and positive controls were treated with a known apoptotic stimulus. Apoptosis was detected by cell morphology changes and by 2 specific apoptotic markers: TUNEL (Terminal transferase dUTP Nick-End Labeling) and Annexin V. These fluorescent markers were detected and quantified by automated Laser Scanning Cytometry. All techniques showed that increased pressure was associated with a greater level of apoptosis compared to equivalent controls. Our results suggest that pressure alone may act as a stimulus for apoptosis in neuronal cell cultures. This raises the possibility of a more direct relationship at the cellular level between pressure and neuronal loss.

Effect of sulfur dioxide inhalation on erythrocyte antioxidant status and lipid peroxidation in experimental diabetes.

The effect of sulfur dioxide (SO(2) ) on red cell antioxidant status and lipid peroxidation was examined in this research. Forty healthy male albino rats, aged three months, were divided into four equal groups: Control (C), SO(2) +C (CSO(2) ), diabetic (D) and SO(2) +D (DSO(2) ). Experimental diabetes mellitus was induced by i.v injection of alloxan with a dose of 50 mg/kg body weight. Ten ppm SO(2) was administered to the animals of SO(2) exposed groups in an exposure chamber for one hr/day x 7 days/wk x 6wks while other groups were exposed to filtered air in the same condition. SO(2) exposure, while markedly decreasing Cu, Zn-Superoxide dismutase (Cu, Zn-SOD) activity, significantly increased glutathione peroxidase (GSH-Px), catalase (CAT), glutathione (GSH) and glutathione-s-transferase (GST) activities and TBARS values in CSO(2) and DSO(2) groups compared with their respective control groups. From these results, it could be concluded that adaptative changes occurred in antioxidant systems that may counteract the free radical effect of SO(2) in the experimental 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.

Age-related alterations in antioxidant enzymes, lipid peroxide levels, and somatosensory-evoked potentials: effect of sulfur dioxide.

The effect of sulfur dioxide (SO(2)) on somatosensory-evoked potentials (SEPs), thiobarbituric acid reactive substances (TBARS), and the activities of Cu,Zn-superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) were investigated in young (3 months), middle-age (12 months), and old (24 months) Swiss male albino rats. Ten ppm SO(2) was administrated to the animals of SO(2) groups in an exposure chamber for 1 h/day x 7 days/week x 6 while control groups were exposed to filtered air in the same condition. SO(2) exposure caused increased levels of brain Cu,Zn-SOD activity and decreased levels of brain GSH-Px activity in all experimental groups with respect to their corresponding control groups. Brain CAT activities were unaltered. Brain TBARS levels of all SO(2)-exposed groups were significantly increased in comparison with their respective control groups. The mean latencies of P(1), P(2), and N(2) components in the older group were either significantly different from the young or from the middle-age groups. The mean latency of the N(1) component in the older group and that of P(1) and N(1) in the middle-age group were significantly increased compared with the young group. SO(2) exposure caused the prolongation of all components in the young group, whereas it affected only the P(2) component in the middle-age group, but it did not result in any latency change in the older group in comparison with their corresponding control groups.http://link.springer-ny. com/link/service/journals/00244/bibs/37n4p554.html

Effect of cadmium-induced lipid peroxidation on EEG spectral components.

Pregnant Swiss albino rats were divided into control (C) and cadmium (Cd) groups. Control animals received tap water while the Cd group received Cd as CdCl2 in their drinking water. The rat pups were separated from their mothers 22 days after birth. 78 young rats were divided into two main groups: controls (C1, C2, C4) and cadmium groups (Cd1, Cd2, Cd4). Each sub-group included 13 rats. On postnatal days 30, 60, and 120, spectral analysis of EEGs recorded from the parietal lobes of all groups of rats was computed by fast Fourier transform (FFT) algorithm. The amplitude maxima were found to occupy the frequency bands of 1-2, 2-4, 4-6, 6-8, 8-16, and 16-30 Hz. The decibel (dB) values of the maxima were significantly decreased in Cd1 and Cd2 groups compared with the corresponding control groups in all the frequency bands except 16-30 Hz. A significant amplitude (dB) decrease was observed in all the frequency bands of the Cd4 group compared with the C4 group.