Cage Control Group Research Articles

Chronic Sleep Disturbance Impairs Glucose Homeostasis in Rats

Epidemiological studies have shown an association between short or disrupted sleep and an increased risk for metabolic disorders. To assess a possible causal relationship, we examined the effects of experimental sleep disturbance on glucose regulation in Wistar rats under controlled laboratory conditions. Three groups of animals were used: a sleep restriction group (RS), a group subjected to moderate sleep disturbance without restriction of sleep time (DS), and a home cage control group. To establish changes in glucose regulation, animals were subjected to intravenous glucose tolerance tests (IVGTTs) before and after 1 or 8 days of sleep restriction or disturbance. Data show that both RS and DS reduce body weight without affecting food intake and also lead to hyperglycemia and decreased insulin levels during an IVGTT. Acute sleep disturbance also caused hyperglycemia during an IVGTT, yet, without affecting the insulin response. In conclusion, both moderate and severe disturbances of sleep markedly affect glucose homeostasis and body weight control.

Adaptations to high-intensity intermittent exercise in rodents

In humans, exercise-induced plasma volume (PV) expansion is typically associated with an increase in plasma albumin content, due in part to an increase in hepatic albumin synthesis. We tested the ability of a 12-day high-intensity intermittent exercise protocol to induce an increase in PV in rodents. Since albumin synthesis is transcriptionally regulated, we tested the hypothesis that exercise training would induce an increase in hepatic albumin gene expression. Fifty adult male Sprague-Dawley rats weighing between 245 and 350 g were randomly assigned to one of five groups: cage control (CC), sham exercise (sham), continuous moderate-intensity exercise training (MI), high-intensity intermittent exercise training (HI), or a single day of HI training (1-HI). Twenty-four hours after the last training session, rats were anesthetized. PV was determined, and the liver was removed, flash frozen, and stored for later analysis. Citrate synthase (CS) activity of the red quadriceps muscle, a marker of aerobic adaptation, increased with training (MI and HI) and in response to 1-HI (P < 0.05). We did not see a significant exercise-induced PV expansion as PV averaged 23.6 +/- 2.7 ml/kg body wt in the CC group and 26.6 +/- 1.3 ml/kg body wt in the HI group (P > 0.05). However, hepatic albumin mRNA expression, as determined by real-time PCR, increased 2.9 +/- 0.4- and 4.1 +/- 0.4-fold after MI and HI, respectively, compared with CC. A single bout of HI (1-HI) did not alter hepatic albumin mRNA expression. These data demonstrate an increase in both CS activity and hepatic albumin gene expression with 12 days of aerobic exercise training in the rodent with a rapid (within 24 h) adaptation in the skeletal muscle to high-intensity intermittent exercise.

Intergeniculate leaflet c‐Fos induction is attenuated in mice lacking normal vestibular input

The circadian pacemaker can be phase shifted by appropriately timed locomotor activity, however the mechanism(s) involved remain poorly understood. Investigations suggest the intergeniculate leaflet of the thalamus is an integral part of the pathway utilized by locomotor stimuli in modulation of the circadian timing system (CTS). We have demonstrated a role for the neurovestibular system in phase shifts of the pacemaker in mice exposed to the gravitoinertial input associated with locomotion. This study tested the hypothesis that timed access to a running wheel would induce IGL c‐Fos in only those animals with functional input from the vestibular macular organs. This study used head tilt (het) mice lacking vestibular otoconia, chemically labyrinthectomized (Labx) mice and wildtype (WT) littermates. After 10 days in constant darkness, animals were assigned to either a running‐wheel pulse (WP) or cage control (CC) group. At circadian time (CT) 4, WP mice were moved to a running wheel and CC mice to a wheel‐free cage. At CT 8, animals were sacrificed and brain tissue processed for histology. We found significantly more IGL c‐fos in WP WT mice than in CC WT or het or Labx mice in either condition. The increase in IGL c‐fos induction among only WT mice supports the role of macular gravity receptive cells in modulation of the CTS while also providing a functional mechanism by which locomotor activity may affect the pacemaker.

Long‐term treadmill exposure protects against age‐related neurodegenerative change in the rat hippocampus

The potential of exercise or environmental enrichment to prevent or reverse age-related cognitive decline in rats has been widely investigated. The data suggest that the efficacy of these interventions as neuroprotectants may depend upon the duration and nature of the protocols and age of onset. Investigations of the mechanisms underlying these neuroprotective strategies indicate a potential role for the neurotrophin family of proteins, including nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF). In this study, we have assessed the effects of 8 months of forced exercise, begun in middle-age, on the expression of long-term potentiation (LTP) and on spatial learning in the Morris water maze in aged Wistar rats. We also assessed these measures in a cage control group and in a group of rats exposed to the stationary treadmill for the same duration as the exercised rats. Our data confirm an age-related decline in expression of LTP and in spatial learning concomitant with decreased expression of NGF and BDNF mRNA in dentate gyrus (DG). The age-related impairments in both plasticity and growth factor expression were prevented in the long-term exercised group and, surprisingly, the treadmill control group. Given the extensive handling that the treadmill control group received and their regular exposure to an environment outside the home cage, this group can be considered to have experienced environmentally enriched conditions when compared with the cage control group. Significant correlations were observed between both learning and LTP and the expression of NGF and BDNF mRNA in the dentate gyrus. We conclude that decreased expression of NGF and BDNF in the dentate gyrus of aged rats is associated with impaired LTP and spatial learning. We suggest that the reversal of these age-related impairments by enrichment and exercise may be linked with prevention of the age-related decline in expression of these growth factors and, furthermore, that enrichment is as efficacious as exercise in preventing this age-related decline.

Effect of Mobile Phone Exposure on Apoptotic Glial Cells and Status of Oxidative Stress in Rat Brain

The aim of this study was to investigate the effects of mobile phone exposure on glial cells in brain. The study carried out on 31 Wistar Albino adult male rats. The rat heads in a carousel exposed to 900 MHz microwave. For the study group (n:14), rats exposed to the radiation 2h per day (7 days in a week) for 10 months. For the sham group (n:7), rats were placed into the carousel and the same procedure was applied except that the generator was turned off. For the cage control (n:10), nothing applied to rats in this group. In this study, rats were euthanized after 10 months of exposure periods and brains were removed.Brain tissues were immunohistochemically stained for the active (cleaved) caspase-3, which is a well-known apoptosis marker, and p53. The expression of the proteins was evaluated by a semi-quantitative scoring system. However, total antioxidative capacity (TAC), catalase, total oxidant status (TOS), and oxidative stress index were measured in rat brain.Final score for apoptosis in the exposed group was significantly lower than the sham (p < 0.001) and the cage control groups (p < 0.01). p53 was not significantly changed by the exposure (p > 0.05). The total antioxidant capacity and catalase in the experimental group was found higher than that in the sham group (p < 0.001, p < 0.05). In terms of the TOS and oxidative stress index, there was no statistically significant difference between exposure and sham groups (p > 0.05).In conclusion, the final score for apoptosis, total antioxidant capacity and catalase in rat brain might be altered by 900 MHz radiation produced by a generator to represent exposure of global systems for mobile communication (GSM) cellular phones.

Treatment of osteoporosis by long-term magnetic field with extremely low frequency in rats

Background. Osteoporosis is characterised by low bone mass and structural deterioration of bone tissue. In this study, the role of long-term extremely low frequency magnetic field (ELFMF) on osteoporosis was evaluated.Methods. The experiments were performed on 45 female Sprague-Dawley rats. The rats were divided into three groups (n = 15): Group I (ovariectomy (OVX) + ELFMF exposure), Group II (ovariectomised rats did not receive any treatment) and Group III (cage-control). Six months, 50 Hz, 1.5 mT magnetic field (MF) was used on Group I and Group II. Total body images of the animals were obtained with dual-energy X-ray absorptiometry.Results. Bone mineral content (BMC) and bone mineral density values were increased significantly in ELFMF group, decreased in the group of OVX and not changed in cage-control. At the end of the 6 months after exposure with ELFMF, alteration in studied biochemical markers were detected significant. Bone specific alkaline phosphatase (BAP) levels were increased in ELFMF and decreased in OVX groups when compared with cage-control group. N-telopeptide levels in OVX group were significantly higher than other groups. Testosterone and cortisol levels in OVX group were significantly higher and estradiol was lower than other groups.Conclusions. Our study suggests that ELFMF may be useful in the prevention and treatment of osteoporosis.

Dietary fish oil did not prevent sleep deprived rats from a reduction in adipose tissue adiponectin gene expression

Sleep deprivation in humans has been related to weight gain and consequently, increased risk for insulin resistance. In contrast, there is a significant loss of weight in sleep deprived rats suggesting a state of insulin resistance without obesity interference. Thus, we aimed to assess the effects of a rich fish oil dietetic intervention on glucose tolerance, serum insulin and adiponectin, and adipose tissue gene expression of adiponectin and TNF-α of paradoxically sleep deprived (PSD) rats. The study was performed in thirty day-old male Wistar randomly assigned into two groups: rats fed with control diet (soybean oil as source of fat) and rats fed with a fish oil rich diet. After 45 days of treatment, the animals were submitted to PSD or maintained as home cage control group for 96 h. Body weight and food intake were carefully monitored in all groups. At the end of PSD period, a glucose tolerance test was performed and the total blood and adipose tissues were collected. Serum insulin and adiponectin were analyzed. Adipose tissues were used for RT-PCR to estimate the gene expression of adiponectin and TNF-α. Results showed that although fish oil diet did not exert any effect upon these measurements, PSD induced a reduction in adiponectin gene expression of retroperitoneal adipose tissues, with no change in serum adiponectin concentration or in adiponectin and TNF-α gene expression of epididymal adipose tissue. Thus, the stress induced by sleep deprivation lead to a desbalance of adiponectin gene expression.

Effect of Mobile Phones on Trace Elements Content in Rat Teeth

ABSTRACTWidespread use of wireless communication made it necessary to investigate the long term effect of mobile phone, which is the most popular technological equipment in the earth. One of the important parts of body that absorbs radiation emitted from mobile phones is oral tissue. However, mobile phone users and also scientists usually do not pay attention on effect of mobile phone exposure on oral tissue. Therefore, there is no epidemiological and experimental studies focused on this part of body. The aim of this study was to investigate the effect of GSM (Global System for Mobile Communication) -Modulated 900 MHz radiofrequency radiation on trace element content of rat teeth. Thirty one Wistar Albino adult male rats were divided into three groups: experimental group (each, n=14), shame group (n=7), and cage control group (n=10). Head of the rats in the experimental group were exposed to GSM-Modulated 900 MHz radiofrequency radiation for 2 hours per day during ten months. At the end of the exposure period, the contents of some trace elements as Ca, Mg, Zn, and P were measured in the oral tissue. The measurements were performed by Atomic Absorption Spectrophotometry (AAS). However, phosphorus content of teeth was measured by ultraviolet spectrophotometer (UVS).Changes of Mg, and Zn contents in the experimental group were found to be statistically significant according to the sham and cage control groups. Ca and P contents in the experimental group were higher than the sham and cage control groups. Difference between the groups was not statistically significant (p>0.05). The results of the study showed that GSM-Modulated 900 MHz radiofrequency radiation can be a factor to alter the teeth trace elements' densities. However, further studies are necessary to know whether GSM-Modulated 900 MHz radiofrequency radiations affects the oral tissues such as the teeth.

Effect of Long Term Mobile Phone Exposure on Oxidative-Antioxidative Processes and Nitric Oxide in Rats

ABSTRACTThe effects of radiation emitted from cellular phones on humans are an emerging area of investigation. The previous studies have shown the role of oxidative stress and NO at radiofrequency exposed rats. Therefore, the purpose of this study was to investigate the effect of microwave/radiofrequency emitted from mobile phones and its possible oxidative damage. Wistar Albino rats were divided into three groups as exposure, sham and cage control. Rats in exposure group were exposed to 900 MHz microwave radiation (0.0782 mW/cm2) in a carousel for 2 hours/7 days in a week during ten months. The same process was applied to sham group but the generator was turned off. Rats in cage control group were kept in cage only during the study. The levels of catalase (CAT), myeloperoxidase (MPO), malondialdehyde (MDA), total antioxidant capacity (TAC), total oxidant status (TOS), oxidative stress index (OSI) in liver and nitric oxide (NO) levels in serum were determined to demonstrate the role of oxidative mechanisms. The increase of nitric oxide levels in exposure and sham groups were found significant compared to cage control group (p<0.01, p<0.05). Although serum NO levels increased in exposed rats, the difference between exposure and sham groups was not significant (p>0.05). MDA and TOS levels in liver tissue were found higher in exposed group compared to sham and cage control group (p<0.05). However, no significant alterations were found in other endpoints such as CAT, MPO, TAC and OSI. In this study we showed that 900 MHz radiofrequency radiation emitted from mobile phones exhibited an increase on MDA and TOS levels. Therefore, RF radiation emitted from GSM cellular phone may play a role to induce oxidative damage by increasing lipid peroxidation and oxidative stress.

GSM and DCS Wireless Communication Signals: Combined Chronic Toxicity/Carcinogenicity Study in the Wistar Rat

A total of 1170 rats comprised of 65 male and 65 female Han Wistar rats per group were exposed for 2 h/day, 5 days/ week for up to 104 weeks to GSM or DCS wireless communication signals at three nominal SARs of 0.44, 1.33 and 4.0 W/kg. A preliminary study confirmed that the highest exposure level was below that which was capable of causing a measurable increase in the core temperature of the rat. Additional groups for each modulation were sham exposed, and there was also an unrestrained, unexposed (cage) control group. Fifteen male and 15 female rats per group were killed after 52 weeks. From the remaining 50 male and 50 female rats per group, surviving animals were killed after 104 weeks. Evaluations during the study included mortality rate, clinical signs, recording of palpable masses, body weight, food consumption, ophthalmoscopic examination, and clinical pathological investigations. Terminal investigations included organ weight measurement and macroscopic and microscopic pathology examinations. There was no adverse response to the wireless communication signals. In particular, there were no significant differences in the incidence of primary neoplasms, the number of rats with more than one primary neoplasm, the multiplicity and latency of neoplasms, the number of rats with metastases, and the number of benign and malignant neoplasms between the rats exposed to wireless communication signals and rats that were sham exposed.

Study on potential effects of “902-MHz GSM-type Wireless Communication Signals” on DMBA-induced mammary tumours in Sprague–Dawley rats

The aim of the study was to detect whether long-term exposure to “902-MHz GSM-type Wireless Communication Signals” (“radio-frequency (RF)-exposure”) would affect 7,12-dimethylbenz(a)anthracene (DMBA)-induced mammary tumours in female Sprague–Dawley rats. Five hundred female rats were each given a single oral dose of 17 mg DMBA per kg body weight (bw) at an age of 46–48 days. Three groups of 100 animals each were RF-exposed (902 MHz; crest factor 8; pulse width = 0.57 ms) from the next day onwards to normal whole-body averaged doses (expressed as specific absorption rate, SAR) of 0.4, 1.3 or 4.0 W/kg bw (low/mid/high-dose group) for 4 h/d, 5 d/week, during 6 months. A sham-exposed and a cage-control group remained without RF-exposure (≪0.01 mW/kg). Animals were weekly weighed and palpated for mammary tumours; all mammary glands were examined histopathologically. There were several statistically significant differences between RF-exposed groups and the sham-exposed group, as follows: All RF-exposed groups had, at different times, significantly more palpable tissue masses. There were fewer animals with benign neoplasms, but more with malignant tumours in the high-dose group. In addition, there were more adenocarcinomas in the low-dose group, more malignant neoplasms in the low- and high-dose groups, more animals with adenocarcinomas in the high-dose group, and fewer animals with fibroadenomas in the low- and mid-dose groups. The cage-control group had, when compared with the sham-exposed group, statistically significantly more palpable tissue masses, more benign and also more malignant neoplasms. The cage-control group had in most aspects the highest incidence and malignancy of neoplasms among all groups. None of the above findings in RF-exposed animals produced a clear dose–response relation and the responses of the cage-control group were either similar to or stronger than those of any of the RF-exposed group. The significant differences between the sham-exposed animals and one or more RF-exposed groups may be interpreted as evidence of an effect of RF-exposure. In the context of the results of the cage-control group, in the light of controversial results reported in the literature, and given the fact that the DMBA-mammary tumour model is known to be prone to high variations in the results, it is the authors’ opinion that the differences between the groups are rather incidental ones.

Mobile Phone Exposure Does Not Induce Apoptosis on Spermatogenesis in Rats

Some studies have reported that microwave radiation can have adverse effects on reproduction. Therefore, the purpose of this study was to investigate the apoptosis-inducing effect of mobile phone exposure on spermatogonia in seminiferous tubules. The study was carried out on 31 Wistar albino adult male rats. The rats were separated into three groups in this study (cage control: 10, sham group: 7, and exposed group: 14). For the study group, rats were exposed to radiation 2 h/day (7 days/week) for 10 months. For the sham group, rats were placed into the carousel and the same procedure was applied except that the generator was turned off. For the cage control, nothing was applied to the rats in this group and they completed their life cycle in the cage during the study period. In this study, rats were sacrificed after 10 months of exposure and their testes were taken. Testes tissue was immunohistochemically stained for the active (cleaved) caspase-3. Positively stained cells were counted in up to ten different areas, and the frequency of positive cells was determined in percentage. Scoring was done by taking into account both the intensity of staining and the distribution of positively stained cells. Therefore, protein expression was evaluated by a semiquantitative scoring system. The final score for apoptosis of testes in the exposed group was not statistically significant according to the sham and the cage control groups (p>0.05). The results of this study showed that 2 h/day (7 days/week) exposure of 900 MHz radiation over a period of 10 months does not affect the active (cleaved) caspase-3 levels in testes, a well-known feature of typical apoptosis.

The nociceptin/orphanin FQ antagonist UFP-101 differentially modulates the glucocorticoid response to restraint stress in rats during the peak and nadir phases of the hypothalamo–pituitary–adrenal axis circadian rhythm

The involvement of nociceptin (N/OFQ) and the nociceptin/orphanin FQ peptide (NOP) receptor in behavior associated with stress and anxiety has been established but their role in the regulation of the hypothalamo–pituitary–adrenal (HPA) axis under conditions of stress has not been fully investigated. We used the selective NOP receptor antagonist UFP-101 to examine the contribution of endogenous N/OFQ to HPA axis control under conditions of restraint stress in the morning and the evening. We found that in the morning during the HPA axis circadian nadir rats exposed to restraint stress in both the presence and absence of UFP-101 exhibited significantly elevated plasma corticosterone at 30 min post-i.c.v. injection compared to the home cage control group. Additionally, rats treated with UFP-101 and exposed to restraint had significantly elevated corticosterone levels at 60 min post-i.c.v. injection compared to all other treatment groups. Interestingly, while there was a significant increase in the expression of CRF mRNA in the paraventricular nucleus (PVN) of rats exposed to restraint stress only, there was no comparable increase in those co-treated with UFP-101. There was no change in the expression of AVP or POMC mRNA in any of the treatment groups. In contrast, when carried out in the evening we observed significantly elevated plasma corticosterone in the vehicle-treated restraint group only at 30 min post-i.c.v. injection. There was no significant difference between the UFP-101-treated restraint group and either of the home cage control groups or the vehicle-treated restraint group. Additionally, in contrast to the morning study, UFP-101 did not prolong glucocorticoid release at the 60 min time-point. These results demonstrate for the first time a differential effect of UFP-101 on restraint stress-induced HPA axis activity characterized by significant prolongation of stress-induced activity in the morning but no significant effect on the response to restraint in the evening.

Hemorrhage near fetal rat bone exposed to pulsed ultrasound

Ultrasound-induced hemorrhage near the fetal rat skull was investigated to determine if the damage could be correlated with temporal-average intensity. A 0.92-MHz f/1 spherically focused transducer (5.1-cm focal length) was used to expose the skull of 18- to 19-day gestation exteriorized Sprague-Dawley rat fetuses ( n = 197). There were four ultrasound-exposed groups ( n = 36 each), one sham exposed group ( n = 36) and one cage control group ( n = 17). Three of the ultrasound-exposed groups had the same peak compressional (10 MPa)/peak rarefactional (6.7 MPa) pressure but different spatial-peak temporal-average intensities ( I TA ) of 1.9, 4.7 and 9.4 W/cm 2; the pulse repetition frequency (PRF) was varied (100, 250 and 500 Hz, respectively). The fourth ultrasound-exposed group had a peak compressional (6.7 MPa)/peak rarefactional (5.0 MPa) pressure and corresponding I TA of 4.6 W/cm 2; PRF was 500 Hz. Hemorrhage occurrence increased slightly with increasing I TA , as well as peak rarefactional pressure and PRF, but the hemorrhage area did not correlate with any of the exposure parameters. (E-mail: timothybigelow@mail.und.nodak.edu)

Effect of Mobile Phone Exposure on Nitric Oxide Production

P-534 Abstract: The purpose of this study is to investigate the effect of Microwave/radiofrequency emitted from mobile phones on nitric oxide production in adult Swiss Albino rats. 28 rats were used in this study. The rats were divided into three groups such as exposure (n: 14), sham (n: 7) and cage control (n: 7). Rats in exposure groups were exposed to 900 MHz microwave radiation in a carousel for 2 hours/7 days in a week during ten months. Same process was applied to rats in sham group except exposure. Rats in cage control were kept in cage only during the study. At the end of the study, nitric oxide (NO) levels were measured. NO concentration was determined by UV- VIS spectrophotometer. The results of exposure group were compared with sham and cage control. However, sham and cage control rats were also compared with each other. Mann Whitney U test was used to analyze the results. Nitric oxide level of exposed and sham groups was found significant according to cage control group (p< 0.01, p< 0.05). However, enhanced NO level in exposed group was not found statistically significant (p> 0.05).

Exposure to high- and low-light conditions in an open-field test of anxiety increases c-Fos expression in specific subdivisions of the rat basolateral amygdaloid complex

Anxiety states and anxiety-related behaviors appear to be regulated by a distributed and highly interconnected system of forebrain structures including the basolateral amygdaloid complex (basolateral amygdala). Despite a wealth of research examining the role of the basolateral amygdala in anxiety-related behaviors and anxiety states, the specific subdivisions of the basolateral amygdala that are involved in responses to anxiogenic stimuli have not been examined. In this study, we investigated the effects of exposure to a novel open-field environment, with either low- or high-levels of illumination, on expression of the protein product of the immediate-early gene c-Fos in subdivisions of the rat basolateral amygdala. The subdivisions studied included the lateral, ventrolateral and ventromedial parts of the lateral amygdaloid nucleus, the anterior, posterior and ventral parts of the basolateral amygdaloid nucleus and the anterior and posterior part of the basomedial amygdaloid nucleus. Small increases in the number of c-Fos-immunoreactive cells were observed in several, but not all, of the subdivisions of the basolateral amygdala studied following exposure of rats to either the high- or low-light conditions, compared to home cage or handled control groups. Open-field exposure in both the high- and low-light conditions resulted in a marked increase in c-Fos expression in the anterior part of the basolateral amygdaloid nucleus compared to either home cage or handled control groups. These findings point toward anatomical and functional heterogeneity within the basolateral amygdaloid complex and an important role of the anterior part of the basolateral amygdaloid nucleus in the neural mechanisms underlying physiological or behavioral responses to this anxiety-related stimulus.

Suppression of hippocampal plasticity‐related gene expression by sleep deprivation in rats

Previous work shows that sleep deprivation impairs hippocampal-dependent learning and long-term potentiation (LTP). Brain-derived neurotrophic factor (BDNF), cAMP response-element-binding (CREB) and calcium-calmodulin-dependent protein kinase II (CAMKII) are critical modulators of hippocampal-dependent learning and LTP. In the present study we compared the effects of short- (8 h) and intermediate-term (48 h) sleep deprivation (SD) on the expression of BDNF and its downstream targets, Synapsin I, CREB and CAMKII in the neocortex and the hippocampus. Rats were sleep deprived using an intermittent treadmill system which equated total movement in the SD and control treadmill animals (CT), but permitted sustained periods of rest in CT animals. Animals were divided into SD (treadmill schedule: 3 s on/12 s off) and two treadmill control groups, CT1 (15 min on/60 min off) and CT2 (30 min on/120 min off - permitting more sustained sleep). Real-time Taqman RT-PCR was used to measure changes in mRNA; BDNF protein levels were determined using ELISA. In the hippocampus, 8 h treatments reduced BDNF, Synapsin I, CREB and CAMKII gene expression in both SD and control groups. Following 48 h of experimental procedures, the expression of all these four molecular markers of plasticity was reduced in SD and CT1 groups compared to the CT2 and cage control groups. In the hippocampus, BDNF protein levels after 8 h and 48 h treatments paralleled the changes in mRNA. In neocortex, neither 8 h nor 48 h SD or control treatments had significant effects on BDNF, Synapsin I and CAMKII mRNA levels. Stepwise regression analysis suggested that loss of REM sleep underlies the effects of SD on hippocampal BDNF, Synapsin I and CREB mRNA levels, whereas loss of NREM sleep underlies the effects on CAMKII mRNA.

No Effects of Radiofrequency Radiation on 3-Chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone-Induced Tumorigenesis in Female Wistar Rats

This study evaluated possible effects of radiofrequency (RF) radiation on tumorigenesis induced by the mutagen 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX) given in drinking water. Female Wistar rats aged 7 weeks at the beginning of the experiments were randomly divided into four groups of 72 animals: a cage-control group and three MX-exposed groups (a daily average dose of 1.7 mg MX/kg body weight for 104 weeks), of which two were exposed to 900 MHz pulsed RF radiation and the third served as a sham-RF-radiation group. The RF-radiation groups were exposed 2 h per day, 5 days per week for 104 weeks at nominal whole-body average SARs of 0.3 W/kg and 0.9 W/kg. Complete histopathology was performed on the rats of the three MX-exposed groups. The tumor types and incidences observed in the MX-exposed animals were similar to those reported earlier in MX-exposed female Wistar rats. RF radiation did not statistically significantly affect mortality or organ-specific incidence of any tumor type. The only statistically significant difference was an increase in the combined frequency of vascular tumors of the mesenteric lymph nodes in the high-RF-radiation group compared to the sham-RF-radiation group. However, additional histopathological analysis of the cage-control animals suggested that this difference was due to unusually low frequency of this type of tumor in the sham-RF-radiation group rather than a high frequency in the high-RF-radiation group. With respect to non-neoplastic findings, statistically significant differences between the RF-radiation groups and the sham-RF-radiation group were observed only for single findings in the lacrimal glands, lungs, liver and skin. Such changes are commonly seen in aged rats and were considered to be unrelated to RF radiation. The results of the present study do not support co-carcinogenic effects of low-level long-term RF-radiation exposure in rats.

Effects of 3-nitropropionic acid administration on memory and hippocampal lipid peroxidation in sleep-deprived mice

Numerous studies have described memory deficits following sleep deprivation. There is also evidence that the absence of sleep increases brain oxidative stress. The present study investigates the effects of a pro-oxidant agent–3-nitropropionic acid (3-NP)–on hippocampal oxidative stress and passive avoidance performance of sleep-deprived mice. Mice were repeatedly treated i.p. with saline or 5 or 15 mg/kg 3-NP and sleep-deprived for 24 h by the multiple platform method—groups of 4–5 animals placed in water tanks, containing 12 platforms (3 cm in diameter) surrounded by water up to 1 cm beneath the surface or kept in their home cage (control groups). The results showed that: (1) neither a 24 h sleep deprivation period nor 3-NP repeated treatment alone were able to induce memory deficits and increased hippocampal lipid peroxidation; (2) this same protocol of sleep deprivation, combined with 15 mg/kg 3-NP repeated treatment, induced memory deficits and an increase in hippocampal lipid peroxidation. The results support the involvement of hippocampal oxidative stress in the memory deficits induced by sleep deprivation and the hypothesis that normal sleep would prevent oxidative stress.

The Effects of Pulsed 860 MHz Radiofrequency Radiation on the Promotion of Neurogenic Tumors in Rats

In a previous study, this laboratory reported a statistically nonsignificant trend for shortened latency of ethylnitrosourea (ENU)-induced brain tumors in Sprague-Dawley rats exposed to an 860 MHz pulsed radiofrequency (RF) signal. The present study was designed to investigate further any promoting effect of the pulsed RF signal on latency and other characteristics of neurogenic tumors in the progeny of pregnant rats treated with 6.25 or 10 mg/kg ENU. The resulting 1080 offspring were randomized equally by number, sex and ENU dose into pulsed RF, sham and cage control groups. The rats were exposed to the pulsed RF signal 6 h per day 5 days per week; the sham-exposed group was similarly confined for the same periods, and the cage controls were housed in standard cages. An essentially equal number of rats from each group were killed humanely every 30 days between the ages of 171 and 325 days; 32 rats died and 225 rats were killed when they were moribund. Postmortem examinations on the 1080 rats revealed 38 spinal cord tumors, 191 spinal nerve tumors, 232 cranial nerve tumors, and 823 brain tumors. A methodical study of the tumor characteristics disclosed no evidence that exposure to the pulsed RF signal affected the incidence, malignancy, volume, multiplicity, latency or fatality associated with any kind of neurogenic tumor.