Effects of 60 Hz electric and magnetic fields on maturation of the rat neopallium

This study was undertaken to determine the effects of extremely low frequency (ELF; 60 Hz) electromagnetic (EM) fields on somatic growth and cortical development, as well as biochemical and morphological maturation, of the rat neopallium. On the fifth day of pregnancy, female rats were put in pairs into plastic cages that were housed in a specially constructed apparatus for irradiation under three separate sets of combination and intensity: 1) 1 kV/m and 10 gauss; 2) 100 kV/m and 1 gauss; and 3) 100 kV/m and 10 gauss. The dams were exposed for 23 h daily, from days 5 through 19 postconception after which they were returned to cages outside the exposure apparatus until they littered. The neonates were culled to eight pups per litter. At 0 (birth), 5, 12, and 19 days postnatally, they were killed for biochemical and morphological studies. Another group of pregnant rats was sham-exposed in an identical apparatus, which was not energized, and the pups were used as controls. The irradiated rats exhibited no physical abnormalities, nor did they show brain deformities such as swelling or herniation following exposure to ELF-EM fields. There was no difference in somatic growth between control and exposed rats, but a small reduction in cortical weight was observed in rats exposed at 1 kV/m and 10 gauss, and 100 kV/m and 1 gauss, respectively. Biochemical measurements of DNA. RNA, protein, and cerebroside concentrations indicated that among the three separate exposures, only the neopallium of rats exposed at 1 kV/m and 10 gauss showed a small reduction in DNA level, as well as small reductions in RNA and protein levels. No changes were noticed in cerebroside levels in any exposed animals, and there were no differences in protein/DNA and cerebroside/DNA ratios between control and exposed rats. Morphological observations did not reveal any detectable alterations in the irradiated rats. These results indicate that exposure to ELF-EM fields caused minimal or no changes in somatic growth and cerebral development of the rat. © 1993 Wiley-Liss, Inc.     

Perinatal methadone exposure and brain development: a biochemical study

Abstract— The neurochemical effect of maternally administered methadone (5 mg/kg, DL-methadone-HCI) on the brain (including the olfactory bulbs, cerebellum, and brain stem) and cerebellum of offspring exposed during gestation and/or lactation was studied in 10-, 21-, and 60-day old rats. Brain weights were significantly reduced in all methadone-exposed groups at 10 days of age, while only those rats subjected to methadone during gestation or lactation had deficits in brain weights at day 21; no differences were found at 60 days. Brain DNA content was significantly reduced in all opiate-exposed offspring at every age examined, but RNA/DNA and protein/DNA ratios were only consistently increased in rats of the gestation group. Cerebellar weight was reduced at 10 days in the gestation-lactation pups, at 21 days in rats of the gestation and lactation groups, and at 60 days in animals of the gestation and gestation-lactation groups. Cerebellar DNA content was significantly decreased in pups of the gestation group at every age investigated, but only reduced at 21 days in the lactation group and at 60 days in the gestation-lactation group. Rats in the lactation group had the greatest number of alterations in terms of RNA and protein, with the most noticeable being decreases in mean cellular RNA content on days 21 and 60 and a reduction in the mean cellular protein content on day 60. These data suggest that prenatal and/or postnatal methadone treatment affects the biochemical maturation of the central nervous system; deficits in neurons and/or glia, as well as a reduction in myelination, might be reflected in these changes.     

Chronic exposure to 60-Hz electric fields: Effects on pineal function in the rat

As a component of studies to search for effects of 60-Hz electric field exposure on mammalian endocrine function, concentrations of melatonin, 5-methoxytryptophol, and serotonin-Nacetyl transferase activity were measured in the pineal glands of rats exposed or sham-exposed at 65 kV/m for 30 days. In two replicate experiments there were statistically significant differences between exposed and control rats in that the normal nocturnal increase in pineal melatonin content was depressed in the exposed animals. Concentrations of 5-methoxytryptophol were increased in the pineal glands of the exposed groups when compared to shamexposed controls. An alteration was also observed in serotonin-N-acetyl transferase activity, with lower levels measured in pineal glands from exposed animals.     

Effects of acute and repeated exposure to stress on the hypothalamo-pituitary-adrenocortical activity in mice during postnatal development

Hypothalamo-pituitary-adrenocortical (HPA) response to a mild stressful procedure was investigated in mice at Days 8, 10, 12, and 14 of postnatal development. Pups that were removed from the dam and exposed to a novel odor (clean bedding) for 15 min showed higher plasma corticosterone levels than pups whose mother was removed from the cage for 15 min or unhandled pups at all ages, although statistically significant differences were only evident at Days 12 and 14. Lower HPA axis responding in younger mice was not due to immaturity since 8-day-old mice showed a significant and larger increase of plasma corticosterone levels when separated from the mother and isolated from littermates in the absence of bedding. Mice daily exposed to clean bedding (15 min) for the first 13 days of life did not show reduced plasma corticosterone response when reexposed to the stressor at 14 days of age. Conversely, increased plasma corticosterone levels in dams in response to removal of pups was not detectable after repeated exposure to this manipulation (14 days) regardless of the procedure their pups were submitted to, thus ruling out a role of maternal corticosterone passing through the milk on which the pups were fed. These results demonstrate that 15 min exposure to clean bedding is a noninvasive procedure able to elicit HPA axis response in developing mice over a wide age range without producing habituation.     

Comparative Effects of Ethanol and Malnutrition on the Development of Catecholamine Neurons: Changes in Neurotransmitter Levels

Abstract: The comparative effects of exposure to ethanol and malnutrition on the concentrations of tyrosine and catecholamines in whole brain and selected regions of brain have been studied in the developing rat. These animals were the offspring of optimally nourished rats (control pups), of rats fed a diet with 35% of the calories supplied by ethanol (ETOH pups), or of animals fed a diet calorically equivalent to the latter but lacking ethanol (iso-caloric, 1C pups). These diets were administered to dams either during the last week of gestation (prenatal) or during lactation (postnatal). Tyrosine levels were elevated prior to birth in the prenatal ETOH or IC pups or at 1 and 2 weeks of age in postnatal ETOH or 1C pups as compared with values found in the control offspring. Dopamine concentration in whole brain was significantly lower in prenatal ETOH pups than in prenatal IC pups at 3 weeks of age. Levels in the brains of postnatal ETOH pups were lower than control values, but not relative to animals exposed to 1C diet. Investigation of corpus striatum showed a significant decrease in dopamine concentration compared with control or IC pup values as a result of postnatal exposure to ethanol. Norepinephrine levels in the whole brain of prenatal ETOH pups were consistently 30–40% lower than either control or matched 1C pups during development. At 3 weeks of age, the norepinephrine levels in the hypothalamus of animals exposed to ethanol pre or postnatally were 30–60% lower than values in the corresponding region in either control or 1C pups. In the rat model described, ethanol caused a decrease in catecholamine levels, perhaps solely by affecting the norepinephrine neurons.     

低氧对新生大鼠脾单个核细胞DNA合成及转化的影响

本研究以荧光法测定脾单个核细胞ＤＮＡ合成及ＭＴＴ比色法测定的脾单个核细胞对ＣｏｎＡ的增殖反应,观察模拟高原低氧对出生后１４天大鼠上述两指标的影响,同时也观察了交感神经和副交感神经的活动状态,以初步探讨低氧对上述两指标的作用是如何介导的。结果表明：５ｋｍ海拔高度低氧作用２４ｈ不抑制脾单个细胞ＤＮＡ合成及脾单个核细胞转化,而作用５天时则抑制ＤＮＡ合成及脾单个核细胞转化,分别为对照组的５６．６％（Ｐ＜０．０１）和８６．８％（Ｐ＜０．０５）;７ｋｍ海拔高度低氧作用２４ｈ,ＤＮＡ合成及脾单个核细胞转化均受抑制,分别为对照组的６１．０％（Ｐ＜０．０１）和８１．２％（Ｐ＜０．０１）;７ｋｍ海拔２４ｈ低氧导致脾脏中乙酰胆碱下降,儿茶酚胺升高;用ＤＳＰ－４中枢药理性损毁ＮＥ神经元,可使脾单个核细胞ＤＮＡ合成的抑制程度减弱,脾脏中儿茶酚胺含量下降。这些结果表明低氧可抑制新生大鼠脾单个核细胞的ＤＮＡ合成及转化,并可能与交感神经兴奋及副交感神经抑制有关     

Electric field exposure alters serum melatonin but not pineal melatonin synthesis in male rats

Sprague-Dawley male rats, maintained in a 14:10 h light:dark cycl were exposed for 30 days (starting at 56 days of age) to a 65 kV/m, 60 Hz electric field or to a sham field for 20 h/day beginning at dark onset. Pineal N-acetyltransferase (NAT), hydroxy-indole-o-methyl transferase (HIOMT), and melatonin as well as serum melatonin were assayed. Preliminary data on unexposed animals indicated that samples obtained 4 h into the dark period would reveal either a phase delay or depression in circadian melatonin synthesis and secretion. Exposure to electric fields for 30 days did not alter the expected nighttime increase in pineal NAT, HIOMT, or melatonin. Serum melatonin levels were also increased at night, but the electric field-exposed animals had lower levels than the sham-exposed animals. Concurrent exposure to red light and the electric field or exposure to the electric field at a different time of the day-night period did not reduce melatonin synthesis. These data do not support the hypothesis that chronic electric field exposure reduces pineal melatonin synthesis in young adult male rats. However, serum melatonin levels were reduced by electric field exposure, suggesting the possibility that degradation or tissue uptake of melatonin is stimulated by exposure to electric fields. © 1994 Wiley-Liss, Inc.     

Effect of nonionizing radiation on the purkinje cells of the rat cerebellum

In one experiment, Sprague Dawley rats (16–21 days of gestation) and their offspring were exposed to 100-MHz (CW) electromagnetic radiation at 46 mW/cm² (SAR 2.77 mW/g) for 4 h/day for 97 days. In another experiment, the pregnant rats were irradiated daily from 17 to 21 days of gestation with 2450-MHz (CW) microwaves at 10 mW/cm² (SAR 2 mW/g) for 21 h/day. In a third experiment, 6-day-old rat pups were irradiated 7 h/day for five days with 2450-MHz radiation at 10 mW/cm². Equal numbers of animals were sham irradiated in each group. Quantitative studies of Purkinje cells showed a significant and irreversible decrease in rats irradiated during fetal or fetal and early postnatal life. In animals exposed postnatally, and euthanized immediately after irradiation, significant decrease in the relative number of Purkinje cells was apparent. However, restoration apparently occurred after forty days of recovery.     

Age related changes in total DNA and RNA and incorporation of uridine and thymidine in rat brain

1. Total brain DNA and total brain RNA and the incorporation of thymidine[14C] and uridine[3H] were measured in young and aged rats. 2. From 20 days to the time of sexual maturation, both DNA and RNA levels increase. Total RNA exceeds total DNA at all ages. Comparatively, the ratio of total DNA/RNA is higher in young than in aged animals. 3. The incorporation of thymidine[14C]/g of DNA and of uridine[3H]/g of RNA decreases with age. This decrease is rapid in young animals. After 350 days of age, the incorporation becomes very low. The significance of data is discussed.     

Effects of prenatal administration of testosterone and cortisone on the reproductive system of the female rat.

Testosterone propionate, cortisone, or sesame oil vehicle were given to rats during the last week of pregnancy so that effects of the hormones on anogenital distance, breeding capacity and vaginal opening of the female progeny could be contrasted. Testosterone significantly increased anogenital distance and delayed vaginal opening of progeny. When females that had been exposed to testosterone in utero were tested for breeding capacity, a significantly smaller number mated than in the control group. Female rats that had been exposed to cortisone in utero exhibited premature vaginal opening but did not differ from controls in anogenital distance, and, unlike the testosterone-exposed rats, mated. Cortisone-exposed rats carried litters to term and the litters did not differ from those of controls in numbers of pups or numbers of living pups at birth. The pups born to cortisone-exposed rats had greater birth weights and a higher survival rate to 20 days of age than pups of controls. Results indicate that testosterone administration to rats during pregnancy is far more detrimental to the development and subsequent function of the reproductive system of female progeny than cortisone and suggest that similar changes which occur in response to maternal stress or to administration of ACTH during pregnancy are more likely to result from increases in testosterone than from increases in glucocorticoid secretion.     

The effect on growth of feeding supplemental milk or baby food to the suckling rat

Suckling rats were fed synthetic rat milk or baby food as dietary supplements amounting to 10% of their total expected daily caloric intake from day 10 to day 16 of life. On day 17, their body lipid levels were significantly higher than those of control pups, and they remained high throughout a 6-week postweaning period of ad libitum food intake. Protein content (at 17 and 60 days of age) was similar in experimental and control groups. Seventeen-day-old pups that had been fed supplemental baby food showed a small but significant increase in DNA levels but no accompanying increase in lean body mass. Rats that received supplemental milk weighed more than either those that received baby food or controls at 17 days of age; however, both experimental groups weighed considerably more at weaning (21 days) than controls. At 60 days of age, their weights were again similar to those of control rats.     

Two-year chronic bioassay study of rats exposed to a 1.6 GHz radiofrequency signal

The purpose of this study was to determine whether long-term exposure to a 1.6 GHz radiofrequency (RF) field would affect the incidence of cancer in Fischer 344 rats. Thirty-six timed-pregnant rats were randomly assigned to each of three treatment groups: two groups exposed to a far-field RF Iridium signal and a third group that was sham exposed. Exposures were chosen such that the brain SAR in the fetuses was 0.16 W/kg. Whole-body far-field exposures were initiated at 19 days of gestation and continued at 2 h/day, 7 days/week for dams and pups after parturition until weaning (approximately 23 days old). The offspring (700) of these dams were selected, 90 males and 90 females for each near-field treatment group, with SAR levels in the brain calculated to be as follows: (1) 1.6 W/kg, (2) 0.16 W/kg and (3) near-field sham controls, with an additional 80 males and 80 females as shelf controls. Confining, head-first, near-field exposures of 2 h/day, 5 days/week were initiated when the offspring were 36 +/- 1 days old and continued until the rats were 2 years old. No statistically significant differences were observed among treatment groups for number of live pups/litter, survival index, and weaning weights, nor were there differences in clinical signs or neoplastic lesions among the treatment groups. The percentages of animals surviving at the end of the near-field exposure were not different among the male groups. In females a significant decrease in survival time was observed for the cage control group.     

Islets in early life are resistant to detrimental effects of a high-fat maternal diet: a study in rats

Offspring of rats fed high-fat diets during pregnancy and lactation develop glucose intolerance and islet dysfunction in adulthood. Because other models of developmental programming of glucose intolerance are associated with defective islet development, we investigated whether high-fat exposure during fetal or neonatal life impairs islet development and function, thereby contributing to islet dysfunction in later life. Female rats were fed control or high-fat diets and their pups cross-fostered after birth to represent 4 groups with each combination of control and high-fat diet for the natural and foster mother. In a time course study, pups were kept with the natural mother until weaning. Pancreases were analysed for insulin content, beta cell mass, and islet number. Isolated islets were studied for insulin secretory responses and susceptibility to palmitate-induced apoptosis assessed by caspases 3/9 activity. Pancreatic insulin content and beta cell mass were increased in pups exposed to maternal high-fat diets after birth, whereas glucose-stimulated insulin secretion from islets of high-fat offspring at 5 and 11 days of age was lower than controls. Islets from control rats of 2-14 days of age were resistant to the pro-apoptotic effects of palmitate seen in older animals. The immature beta cell is therefore insensitive to toxic effects of palmitate and may compensate for the inhibitory effects on insulin secretion by increasing beta cell mass. The data suggest that susceptibility to glucose intolerance in offspring of dams fed high-fat diets may not be a consequence of deleterious effects on beta cell mass in early life.     

Endocrinological effects of strong 60-Hz electric fields on rats

Adult male rats were exposed or sham-exposed to 60-Hz electric fields without spark discharges, ozone, or significant levels of other secondary variables. No effects were observed on body weights or plasma hormone levels after 30 days of exposure at an effective field strength of 68 kV/m. After 120 days of exposure (effective field strength = 64 kV/m), effects were inconsistent, with significant reductions in body weight and plasma levels of follicle-stimulating hormone and corticosterone occurring in one replicate experiment but not in the other. Plasma testosterone levels were significantly reduced after 120 days of exposure in one experiment, with a similar but not statistically significant reduction in a replicate experiment. Weanling rats, exposed or sham-exposed in electric fields with an effective field strength of 80 kV/m from 20 to 56 days of age, exhibited identical or closely similar growth trends in body and organ weights. Hormone levels in exposed and sham-exposed groups were also similar. However, there was an apparent phase shift between the two groups in the cyclic variations of concentrations of hormones at different stages of development, particularly with respect to follicle-stimulating hormone and corticosterone. We concluded that 60-Hz electric fields may bring about subtle changes in the endocrine system of rats, and that these changes may be related to alterations in episodic rhythms.     

Effect of electromagnetic radiofrequency radiation on the rats' brain, liver and kidney cells measured by comet assay

The goal of study was to evaluate DNA damage in rat's renal, liver and brain cells after in vivo exposure to radiofrequency/microwave (Rf/Mw) radiation of cellular phone frequencies range. To determine DNA damage, a single cell gel electrophoresis/comet assay was used. Wistar rats (male, 12 week old, approximate body weight 350 g) (N = 9) were exposed to the carrier frequency of 915 MHz with Global System Mobile signal modulation (GSM), power density of 2.4 W/m2, whole body average specific absorption rate SAR of 0.6 W/kg. The animals were irradiated for one hour/day, seven days/week during two weeks period. The exposure set-up was Gigahertz Transversal Electromagnetic Mode Cell (GTEM--cell). Sham irradiated controls (N = 9) were apart of the study. The body temperature was measured before and after exposure. There were no differences in temperature in between control and treated animals. Comet assay parameters such as the tail length and tail intensity were evaluated. In comparison with tail length in controls (13.5 +/- 0.7 microm), the tail was slightly elongated in brain cells of irradiated animals (14.0 +/- 0.3 microm). The tail length obtained for liver (14.5 +/- 0.3 microm) and kidney (13.9 +/- 0.5 microm) homogenates notably differs in comparison with matched sham controls (13.6 +/- 0.3 microm) and (12.9 +/- 0.9 microm). Differences in tail intensity between control and exposed animals were not significant. The results of this study suggest that, under the experimental conditions applied, repeated 915 MHz irradiation could be a cause of DNA breaks in renal and liver cells, but not affect the cell genome at the higher extent compared to the basal damage.     

Myelin Deficits Produced by Early Postnatal Exposure to Inorganic Lead or Triethyltin Are Persistent

Abstract: Long-Evans rat pups were exposed to either inorganic lead (400 mg Pb as lead acetate/kg body weight/day) or triethyltin sulfate (1.0 mg/kg body weight/day), by gastric intubation, from 2 days through 29 days of age. The rats were then weaned and placed on standard lab chow ad libitum. At 30 days of age, leadtreated rats exhibited statistically significant decreases in body and brain weights (22% and 17%, respectively), and the concentration of forebrain myelin was significantly reduced, by 21% relative to the 4.9 mg myelin protein/g brain in control rats. Although these animals recovered from the body weight deficits after several months, the deficits in brain weight and myelin concentration were still present at 120 days of age. This suggests that the lead-induced myelin deficits were permanent. Lead levels in brain, which were maximal at 30 days of age when the treatment was terminated, decreased more slowly than in other organs and were still 30% of maximal levels at 120 days of age. Triethyltin-treated animals also had significantly decreased body and brain weights (20% and 11%, respectively) at 30 days of age, and an even more severe reduction in forebrain myelin concentration (33%). These animals also regained a normal body weight by 120 days of age, but again the deficits in brain weight and myelin concentration persisted. Tin levels in brain and other organs had decreased to control levels by 60 days of age. Animals malnourished by maternal deprivation to match the body weights of the treated animals had myelin deficits that were less severe than those in the treated animals at 30 days of age (approximately 11% less than controls); however, these myelin deficits also persisted throughout the subsequent 90-day recovery period examined. The apparent lack of recovery from CNS myelin deficits produced by neonatal exposure to different heavy metals or to malnutrition reemphasizes the vulnerability of the developing nervous system to a wide range of metabolic insults.     

In utero and early-life exposure of rats to a Wi-Fi signal: screening of immune markers in sera and gestational outcome

An experimental approach was used to assess immunological biomarkers in the sera of young rats exposed in utero and postnatal to non-ionizing radiofrequency fields. Pregnant rats were exposed free-running, 2 h/day and 5 days/week to a 2.45 GHz Wi-Fi signal in a reverberation chamber at whole-body specific absorption rates (SAR) of 0, 0.08, 0.4, and 4 W/kg (with 10, 10, 12, and 9 rats, respectively), while cage control rats were kept in the animal facility (11 rats). Dams were exposed from days 6 to 21 of gestation and then three newborns per litter were further exposed from birth to day 35 postnatal. On day 35 after birth, all pups were sacrificed and sera collected. The screening of sera for antibodies directed against 15 different antigens related to damage and/or pathological markers was conducted using enzyme-linked immunosorbent assay (ELISA). No change in humoral response of young pups was observed, regardless of the types of biomarker and SAR levels. This study also provided some data on gestational outcome following in utero exposure to Wi-Fi signals. Mass evaluation of dams and pups and the number of pups per litter was monitored, and the genital tracts of young rats were observed for abnormalities by measuring anogenital distance. Under these experimental conditions, our observations suggest a lack of adverse effects of Wi-Fi exposure on delivery and general condition of the animals.     

Effect of visual deprivation on protein and nucleic-acid content in cerebral cortex of rats after the eye-opening term

Between postnatal days 10 and 16 the cerebral cortex of rats displayed a rise in protein content and a tendency towards RNA increase, whereas changes in DNA content (cell density) were absent. Young rats whose eyelids had been sutured and covered with black collodion at the age of 7 or 8 days exhibited some developmental retardation already by day 16. At an age of 5 weeks the brains of control, eyelid-sutured and dark-reared rats did not differ in their weight. However, dark-reared rats had a highly significantly increased RNA concentration in the occipital cortex (not differing significantly from controls) than eyelid-sutured animals (p less than 0.005). In the remainder of cortex, eyelid-sutured animals displayed an increase (p less than 0.10) of RNA concentration as compared with controls. The most pronounced intergroup differences were found on comparing RNA, DNA and protein concentrations between occipital and residual cortices within the individual animal groups. The difference was practically nil in control animals; all components were highly significantly raised (RNA: p less than 0.001; DNA: p less than 0.01; protein: p less than 0.001) in the residual cortex in eyelid-sutured animals; dark-reared animals displayed a similar tendency as eyelid-sutured animals that, nevertheless, did not reach statistical significance.     

Adrenocortical responses to ACTH in neonatal rats: effect of hypoxia from birth on corticosterone,StAR, and PBR

The adrenocortical response to hypoxia may be a critical component of the adaptation to this common neonatal stress. Little is known about adrenal function in vivo in hypoxic neonates. The purpose of this study was to evaluate adrenocortical responses to ACTH in suckling rat pups exposed to hypoxia from birth to 5-7 days of age compared with normoxic controls. We also evaluated potential cellular controllers of steroidogenic function in situ. In 7-day-old pups at 0800, hypoxia from birth resulted in increased basal (12.2 +/- 1.4 ng/ml; n = 12) and ACTH-stimulated (94.0 +/- 9.4 ng/ml; n = 14) corticosterone levels compared with normoxic controls (basal = 8.3 +/- 0.5 ng/ml; n = 11; stimulated = 51.3 +/- 3.8 ng/ml; n = 8). This augmentation occurred despite no significant difference in plasma ACTH levels in normoxic vs. hypoxic pups before (85 +/- 4 vs. 78 +/- 8 pg/ml) or after (481 +/- 73 vs. 498 +/- 52 pg/ml) porcine ACTH injection (20 microg/kg). This effect was similar in the afternoon at 6 days of age and even greater at 5 days of age at 0800. The aldosterone response to ACTH was not augmented by exposure to hypoxia from birth. Adrenocortical hypoxia-inducible factor (HIF)-1alpha mRNA was undetectable by RT-PCR. Steroidogenic acute regulatory (StAR) protein in adrenal subcapsules (zona fasciculata/reticularis) was augmented by exposure to hypoxia; this effect was greatest at 5 days of age. Peripheral-type benzodiazepine receptor (PBR) protein was also increased at 6 and 7 days of age in pups exposed to hypoxia from birth. We conclude that hypoxia from birth results in an augmentation of the corticosterone but not aldosterone response to ACTH. This effect appears to be mediated at least in part by an increase in controllers of mitochondrial cholesterol transport (StAR and PBR) and to occur independently of measurable changes in endogenous plasma ACTH. The augmentation of the corticosterone response to acute increases in ACTH in hypoxic pups is likely to be an important component of the overall physiological adaptation to hypoxia in the neonate.     

Influence of pre- and postnatal exposure of rats to 2.45-GHz microwave radiation on neurobehavioral function

Rats exposed to microwaves prenatally (2,450 MHz, 10 mW/cm2, 3 h/day, days 5-20 of gestation) or perinatally (same as above plus days 2-20 postnatally) were examined by a neurobehavioral test battery on postnatal days 30 and 100. Body mass, locomotor activity, startle to acoustic and air-puff stimuli, fore- and hindlimb grip strength, negative geotaxis, reaction to thermal stimulation, and swimming endurance were assessed. The prenatally and the perinatally exposed rats (male and female) weighted more than sham-exposed rats at 30, but not at 100, days of age. In addition, the perinatally exposed animals had less swimming endurance at 30, but not at 100, days of age relative to sham-exposed rats. For the other measures, only the air-puff startle response was altered and was limited to the prenatally exposed female pups; ie, at postnatal day 30, the startle response was increased in magnitude, and at postnatal day 100, the response was decreased. No other reliable effects were observed. In a second experiment, rats treated as described above were examined for alterations in body mass, locomotor activity, reaction to air-puff stimuli, reaction to thermal stimulation, and swimming endurance at postnatal days 30-36. Again, perinatally exposed rats were larger in body mass and had less swimming endurance compared with sham-exposed rats. The latency to the air-puff startle response was longer in female pups exposed prenatally. These data indicate that altered endurance and gross motor activity result from perinatal exposure to microwave irradiation.