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The adverse effects of pesticides on the central auditory nervous system in tobacco growers
122
NBTS / INA 2015 Abstracts
neurochemical and epigenetic bases for this long-term behavioral dysfunction are being investigated. This research was supported by the U.S. Environmental Protection Agency (US EPA) grant RD83543701 and National Institute for Environmental Health Sciences (NIEHS) grant ES022831. doi:10.1016/j.ntt.2015.04.073
NTX68 Effects of environmental exposure to manganese on the visuoperception and visual memory in Mexican children D. Hernández-Bonillaa, C. Escamilla-Nuñeza, Donna Merglerc, A. Schilmann-Halbingera, S. Rodríguez-Dozala, S. Montesb, H. Riojas-Rodrígueza a National Institute of Public Health, Ciudad de Mexico, Mexico b National Institute of Neurologic and Neurosurgery, Manuel Velasco Suarez, Ciudad de Mexico, Mexico c CINBIOSE, Université du Québec à Montréal, Montreal, QC, Canada The Molango mining district located in the state of Hidalgo has important manganese (Mn) deposits. An ecosystem health approach has been used to study the factors that determine the population exposure using the interaction between social, environmental and health sciences. The objective of this study is to evaluate the effect of Mn exposure on visual perception and visual memory in school-aged children. Materials and methods: Cross sectional study. School-aged children between 7 and 11 years old were selected 148 children from two communities exposed in the Molango mining district and 116 children from unexposed communities with similar socioeconomic conditions. The Rey–Osterrieth Complex Figure (ROFC) was applied. The exposure to Mn was measured in hair (MnH). MnH was transformed to natural logarithm. To estimate the association between MnH and the ROFC were used multilevel regression models or hierarchical linear models, assuming that the effects of the predictor variables are fixed. A random term was used for analyzing the difference intergroup. These models were adjusted for confusing variables. Results: Mean arithmetical MnH was significantly different between exposed group (5.25 μg/g) and unexposed group (0.55 μg/g) p b 0.05. We found a statistically significant association between the lnMnH-age interaction and ROCF test. ROCF copy: for each increase lnMnH-age interaction there is an increment in the distortion error (β 0.016, CI 0.003–0.029), tangency errors (β 0.018, CI 0.005–0.031), overtracing (β 0.013, CI 0.000–0.027), overtracing (type A) (β 0.012, CI 0.002–0.022). ROCF Immediate Recall: For each increase of lnMnH-age interaction there is an increment in the distortion error (β 0.027, CI 0.012–0.042), tangency errors (β 0.027 CI 0.013–0.041), incomplete draw (β 0.007 CI 0.001–0.013), angle error (β 0.019 CI 0.010–0.029), overtracing (β 0.011 CI 0.002–0.020), and overtracing (type A) (β 0.010 CI 0.003– 0.017). Conclusions: This study demonstrates that the environmental exposure to Mn has an association about the visuoperception and visual memory in school-aged children. The effects of environmental exposure to Mn about the visuoperception function and visual memory are greater in the girls. doi:10.1016/j.ntt.2015.04.074
NTX69 The effects of lead (Pb) and methylmercury (MeHg) on neurochemistry and behavior in chicken hatchlings Theresa Johnston, Kimmo Mäenpää, Nil Basu McGill, Montreal, Canada
Lead (Pb) and mercury (Hg) have been used by humans for thousands of years, despite their known toxicity. Both of these metals enter the environment through human activities. Hg is converted to more bioavailable methylmercury (MeHg) by bacteria in aquatic sediments. Ecosystems are often subjected to pollution from numerous sources, exposing wildlife to combinations of contaminants. Also heavy metal pollutants, including Pb and MeHg, commonly occur together worldwide and threaten the health of humans and wildlife. Birds are particularly susceptible to Pb and MeHg because of dietary exposure common in both water birds and scavengers. Our understanding of the developmental and neurological effects of these contaminants on avian development is still poor; and while we know that Pb and MeHg individually affect avian behavior, their combined affects have not been previously assessed in birds. The objective of our study was to examine both the individual effects of Pb and MeHg, and their combined effects (Pb + MeHg) on the development, behavior, and neurochemistry of chicken hatchlings by injecting lead nitrate and MeHg into fertilized chicken eggs. The exposures were done at ecologically relevant concentrations. Chicken was used as a model to increase understanding of behavioral and neurotoxicity while also serving as sentinels for wildlife exposures. Mortality and developmental malformations were examined at hatching or during embryonic necropsy. Morphometric assessments were made 3 h post-hatch. This was followed with behavioral assessments at 5 and 10 days post-hatch and neurochemical analysis for effects on NMDA and GABA receptor densities. Malformations were seen in embryos at high doses of Pb. Pb, MeHg, and Pb + MeHg changed the behavioral responses of hatchlings compared to non-exposed individuals. These data help support the notion that Pb can have damaging effects on population size and fitness of birds in the wild. Notably, the behavioral comparisons in this study among Pb, MeHg, Pb + MeHg and controls may reveal important interactions of Pb and MeHg. doi:10.1016/j.ntt.2015.04.075
NTX70 The adverse effects of pesticides on the central auditory nervous system in tobacco growers Adriana Bender Moreira Lacerdaa, Denisa Maria Vaz Romano Françaa, Tony Lerouxb, Adrian Fuenteb a Universidade Tuiuti do Paraná, Curitiba, Brazil b Université de Montréal, Montreal, QC, Canada In Brazil, the plantation of tobacco occupies a very important place in the economy. In tobacco fields, the use of pesticides is massive which has a direct adverse effect on rural workers and their families' health. The aim of this study was to investigate the effects of exposure to agrochemicals on the central auditory system of growers. This was a cross-sectional study carried out between 2010 and 2012. All participants had normal hearing thresholds (for 500, 1000 and 200 Hz) and normal middle-ear function. A total of 20 growers exposed to agrochemicals (study group) and 21 participants who were not exposed to agrochemicals (control group) and with the same educational level as study group participants were selected. Participants were evaluated with two behavioral procedures to investigate the central auditory nervous system, the Random Gap Detection Test (RGDT, to evaluate temporal processing) and the Dichotic Digit Test in Portuguese (DD, to evaluate binaural integration). RGDT is a binaural test which is comprised of 4 subtests (500, 1000, 2000 and 4000 Hz). DD is a dichotic test and thus results are calculated for the right and left ears, and an average score between both ears is also obtained. No significant differences between groups
NBTS / INA 2015 Abstracts
for pure-tone thresholds were observed. A significant association between pesticide exposure and the results for RGDT and DD tests was found. Significant differences between pesticide-exposed and non-exposed subjects were found for RGDT 500 (F = 4.7, p b 0.05), RGDT 1000 (F = 7.3, p b 0.05), RGDT frequency average (F = 5.7, p b 0.05), and DD binaural average (F = 5.0, p b 0.05) when including age and hearing level as covariates. Age was significantly associated with RGDT 500 (F = 6.3, p b 0.05), RGDT frequency average (F = 4.2, p b 0.05), DD left ear (F = 16.7, p b 0.0001), DD binaural average (F = 6.8, p b 0.05), and DD REA (F = 10.7, p b 0.01). Hearing level was not significantly associated with any of the test scores. The results showed that growers exposed to pesticides exhibited signs of central auditory dysfunction. This suggests that agrochemicals are associated with decrements in temporal processing and binaural integration processes/abilities in exposed individuals. doi:10.1016/j.ntt.2015.04.076
NTX71 Study of evoked otoacoustic emissions and suppression effect on workers exposed to pesticides and noise Adriana Bender Moreira de Larcerdaa, Patricia Arruda de Souza Alcarása, Mendes Marquesa, Tony Lerouxb a Universidade Tuiuti do Paraná, Curitiba, Brazil b University of Montréal, Montreal, Canada Scientific literature on the combined effect of exposure to noise and chemical agents on the auditory system is extensive. However, the effects of pesticides were more rarely examined. The purpose of the study was to examine the effects of combined exposure to pesticides and noise in workers using objective measures of the auditory function. The sample consisted of 55 participants with hearing thresholds b25 dBHL, with ages ranging from 18 to 35 years, divided into two groups: one group chronically exposed to noise and pesticides (NPG) and a control group (CG). The NPG was composed of 25 workers exposed to a representative daily level of occupational noise exposure and organophosphate pesticide. All NPG workers were involved in annual campaigns fighting against the dengue mosquito (100%) and exposed daily, during a 6-hour period, to an organophosphate pesticide commercially known as Malathion. The chemical substance is spread using motorized back atomizers, generating a moderate level of noise of 86 dBA when operated, which corresponds to their daily occupational exposure. In addition to hearing protection equipment, all NPG participants (100%) make use of other protection equipment, such as masks, pants, capes, boots, gloves, helmets, goggles. The CG was composed of 30 participants who were not exposed to noise or pesticides. All participants underwent Transient Evoked Otoacoustic Emissions (TEOAE) and Distortion Product Otoacoustic Emissions (DPOAE) assessments and a measure of the suppression effect which allowed examining the integrity of the medial olivocochlear efferent system. Student's t test and Fisher's test were applied to analyze the variability among TEOAE, DPOAE, and suppression effect averages between the NPG and the CG. The findings revealed significant differences for the TEOAE and DPOAE measures between NPG and CG groups. Workers in the NPG showed a reduced signal to noise ratio in both TEOAE and DPOAE measurements. A smaller general response level and a lower suppression value were also observed in the NPG. These findings suggest that chronic combined exposure to pesticides and noise may have altered the auditory function at the level of the medial olivocochlear efferent system. doi:10.1016/j.ntt.2015.04.077
123
NTX72 Assessment of the short-term neurobehavioral toxicity of a perinatal exposure to the hexabromocyclododecane (HBCDD) α-isomer in rats Nicolas Mauricea, Jean-Charles Olrya, Ronan Carioub, Philippe Marchandb, Gaud Dervilly-Pinelb, Bruno Le Bizecb, Angélique Travelc, Catherine Jondrevillea, Henri Schroedera a Université de Lorraine, Vandoeuvre-lès-Nancy, France b LUNAM Université, Nantes, France c ITAVI, Centre INRA de Tours, Nouzilly, France The present study aimed to investigate the developmental neurotoxicity of an early exposure to a-HBCDD through the ingestion of contaminated hen's egg in pregnant and lactating Wistar female rats. Eggs were obtained from hens after 3 months of daily feeding with a-HBCDD-contaminated feed at two levels of exposure, resulting in a content of a-HBCDD within the eggs of 30 and 100 ng/g of lipids, respectively. Female rats were daily administered p.o. with an appropriate volume of the whole egg from the day of fertilization (GD0) to the weaning day for pups (PND21). Thus, fetuses and pups were continuously exposed to HBCDD through the dam over a whole 42-day period including both gestation and lactation. Neurobehavioral development of pups was investigated from PND3 to PND 25 using various tasks including the righting reflex (PND3–5), the grasping reflex (PND4–6), the negative geotaxis (PND8–10) and the locomotor coordination test (PND19–21). Ultrasonic vocalizations of pups were also daily recorded from PND4 to PND16. After weaning, spontaneous motor activity and anxiety-related behavior were examined at PND25 in the open-field and in the elevated-plus maze, respectively. Present results showed a significant decrease in body weight of both pups exposed to the lower HBCDD level from PND3 to PND25, whereas the weight of rat pups exposed to 100 ng/g of HBCDD was not different from controls. During the first 3 weeks of life, impairments in the motor maturation of pups were observed in a dose-dependent manner depending on the test, whereas no significant differences were reported between male and female pups. At PND25, the anxiety level of female rats exposed to the lowest dose of HBCDD (30 ng/g) was significantly reduced whereas it remained unchanged in males. No significant variations were measured in rats exposed to the higher level of HBCD (100 ng/g). These results suggest the potent developmental neurotoxicity of an early chronic exposure to the HBCDD α-isomer through the ingestion of hen's eggs contaminated with this pollutant and question the long-lasting consequences of this exposure on behavior abilities and brain functioning in adulthood. doi:10.1016/j.ntt.2015.04.078
NTX73 Role of opioids in hemin-induced neurotoxicity Hannah Mick, Shekher Mohan Marshall University, School of Pharmacy, Huntington, WV, USA Background: Intracerebral hemorrhagic (ICH) stroke is defined by the rupture of intracranial artery that leads to the formation of a hematoma. Neuronal damage is associated with the lysis of red blood cells, which releases hemoglobin. Hemoglobin and its breakdown product hemin are neurotoxic. Increasing evidence suggests that drug abuse in the form of opioids can precede and contribute to the pathology of ICH brain injury. The role of opioids and their cognate receptors in hemin-induced neurotoxicity remains unclear. Hypothesis: We hypothesize that morphine may exacerbate and naltrexone may protect against hemin-induced toxicity.
NBTS / INA 2015 Abstracts
neurochemical and epigenetic bases for this long-term behavioral dysfunction are being investigated. This research was supported by the U.S. Environmental Protection Agency (US EPA) grant RD83543701 and National Institute for Environmental Health Sciences (NIEHS) grant ES022831. doi:10.1016/j.ntt.2015.04.073
NTX68 Effects of environmental exposure to manganese on the visuoperception and visual memory in Mexican children D. Hernández-Bonillaa, C. Escamilla-Nuñeza, Donna Merglerc, A. Schilmann-Halbingera, S. Rodríguez-Dozala, S. Montesb, H. Riojas-Rodrígueza a National Institute of Public Health, Ciudad de Mexico, Mexico b National Institute of Neurologic and Neurosurgery, Manuel Velasco Suarez, Ciudad de Mexico, Mexico c CINBIOSE, Université du Québec à Montréal, Montreal, QC, Canada The Molango mining district located in the state of Hidalgo has important manganese (Mn) deposits. An ecosystem health approach has been used to study the factors that determine the population exposure using the interaction between social, environmental and health sciences. The objective of this study is to evaluate the effect of Mn exposure on visual perception and visual memory in school-aged children. Materials and methods: Cross sectional study. School-aged children between 7 and 11 years old were selected 148 children from two communities exposed in the Molango mining district and 116 children from unexposed communities with similar socioeconomic conditions. The Rey–Osterrieth Complex Figure (ROFC) was applied. The exposure to Mn was measured in hair (MnH). MnH was transformed to natural logarithm. To estimate the association between MnH and the ROFC were used multilevel regression models or hierarchical linear models, assuming that the effects of the predictor variables are fixed. A random term was used for analyzing the difference intergroup. These models were adjusted for confusing variables. Results: Mean arithmetical MnH was significantly different between exposed group (5.25 μg/g) and unexposed group (0.55 μg/g) p b 0.05. We found a statistically significant association between the lnMnH-age interaction and ROCF test. ROCF copy: for each increase lnMnH-age interaction there is an increment in the distortion error (β 0.016, CI 0.003–0.029), tangency errors (β 0.018, CI 0.005–0.031), overtracing (β 0.013, CI 0.000–0.027), overtracing (type A) (β 0.012, CI 0.002–0.022). ROCF Immediate Recall: For each increase of lnMnH-age interaction there is an increment in the distortion error (β 0.027, CI 0.012–0.042), tangency errors (β 0.027 CI 0.013–0.041), incomplete draw (β 0.007 CI 0.001–0.013), angle error (β 0.019 CI 0.010–0.029), overtracing (β 0.011 CI 0.002–0.020), and overtracing (type A) (β 0.010 CI 0.003– 0.017). Conclusions: This study demonstrates that the environmental exposure to Mn has an association about the visuoperception and visual memory in school-aged children. The effects of environmental exposure to Mn about the visuoperception function and visual memory are greater in the girls. doi:10.1016/j.ntt.2015.04.074
NTX69 The effects of lead (Pb) and methylmercury (MeHg) on neurochemistry and behavior in chicken hatchlings Theresa Johnston, Kimmo Mäenpää, Nil Basu McGill, Montreal, Canada
Lead (Pb) and mercury (Hg) have been used by humans for thousands of years, despite their known toxicity. Both of these metals enter the environment through human activities. Hg is converted to more bioavailable methylmercury (MeHg) by bacteria in aquatic sediments. Ecosystems are often subjected to pollution from numerous sources, exposing wildlife to combinations of contaminants. Also heavy metal pollutants, including Pb and MeHg, commonly occur together worldwide and threaten the health of humans and wildlife. Birds are particularly susceptible to Pb and MeHg because of dietary exposure common in both water birds and scavengers. Our understanding of the developmental and neurological effects of these contaminants on avian development is still poor; and while we know that Pb and MeHg individually affect avian behavior, their combined affects have not been previously assessed in birds. The objective of our study was to examine both the individual effects of Pb and MeHg, and their combined effects (Pb + MeHg) on the development, behavior, and neurochemistry of chicken hatchlings by injecting lead nitrate and MeHg into fertilized chicken eggs. The exposures were done at ecologically relevant concentrations. Chicken was used as a model to increase understanding of behavioral and neurotoxicity while also serving as sentinels for wildlife exposures. Mortality and developmental malformations were examined at hatching or during embryonic necropsy. Morphometric assessments were made 3 h post-hatch. This was followed with behavioral assessments at 5 and 10 days post-hatch and neurochemical analysis for effects on NMDA and GABA receptor densities. Malformations were seen in embryos at high doses of Pb. Pb, MeHg, and Pb + MeHg changed the behavioral responses of hatchlings compared to non-exposed individuals. These data help support the notion that Pb can have damaging effects on population size and fitness of birds in the wild. Notably, the behavioral comparisons in this study among Pb, MeHg, Pb + MeHg and controls may reveal important interactions of Pb and MeHg. doi:10.1016/j.ntt.2015.04.075
NTX70 The adverse effects of pesticides on the central auditory nervous system in tobacco growers Adriana Bender Moreira Lacerdaa, Denisa Maria Vaz Romano Françaa, Tony Lerouxb, Adrian Fuenteb a Universidade Tuiuti do Paraná, Curitiba, Brazil b Université de Montréal, Montreal, QC, Canada In Brazil, the plantation of tobacco occupies a very important place in the economy. In tobacco fields, the use of pesticides is massive which has a direct adverse effect on rural workers and their families' health. The aim of this study was to investigate the effects of exposure to agrochemicals on the central auditory system of growers. This was a cross-sectional study carried out between 2010 and 2012. All participants had normal hearing thresholds (for 500, 1000 and 200 Hz) and normal middle-ear function. A total of 20 growers exposed to agrochemicals (study group) and 21 participants who were not exposed to agrochemicals (control group) and with the same educational level as study group participants were selected. Participants were evaluated with two behavioral procedures to investigate the central auditory nervous system, the Random Gap Detection Test (RGDT, to evaluate temporal processing) and the Dichotic Digit Test in Portuguese (DD, to evaluate binaural integration). RGDT is a binaural test which is comprised of 4 subtests (500, 1000, 2000 and 4000 Hz). DD is a dichotic test and thus results are calculated for the right and left ears, and an average score between both ears is also obtained. No significant differences between groups
NBTS / INA 2015 Abstracts
for pure-tone thresholds were observed. A significant association between pesticide exposure and the results for RGDT and DD tests was found. Significant differences between pesticide-exposed and non-exposed subjects were found for RGDT 500 (F = 4.7, p b 0.05), RGDT 1000 (F = 7.3, p b 0.05), RGDT frequency average (F = 5.7, p b 0.05), and DD binaural average (F = 5.0, p b 0.05) when including age and hearing level as covariates. Age was significantly associated with RGDT 500 (F = 6.3, p b 0.05), RGDT frequency average (F = 4.2, p b 0.05), DD left ear (F = 16.7, p b 0.0001), DD binaural average (F = 6.8, p b 0.05), and DD REA (F = 10.7, p b 0.01). Hearing level was not significantly associated with any of the test scores. The results showed that growers exposed to pesticides exhibited signs of central auditory dysfunction. This suggests that agrochemicals are associated with decrements in temporal processing and binaural integration processes/abilities in exposed individuals. doi:10.1016/j.ntt.2015.04.076
NTX71 Study of evoked otoacoustic emissions and suppression effect on workers exposed to pesticides and noise Adriana Bender Moreira de Larcerdaa, Patricia Arruda de Souza Alcarása, Mendes Marquesa, Tony Lerouxb a Universidade Tuiuti do Paraná, Curitiba, Brazil b University of Montréal, Montreal, Canada Scientific literature on the combined effect of exposure to noise and chemical agents on the auditory system is extensive. However, the effects of pesticides were more rarely examined. The purpose of the study was to examine the effects of combined exposure to pesticides and noise in workers using objective measures of the auditory function. The sample consisted of 55 participants with hearing thresholds b25 dBHL, with ages ranging from 18 to 35 years, divided into two groups: one group chronically exposed to noise and pesticides (NPG) and a control group (CG). The NPG was composed of 25 workers exposed to a representative daily level of occupational noise exposure and organophosphate pesticide. All NPG workers were involved in annual campaigns fighting against the dengue mosquito (100%) and exposed daily, during a 6-hour period, to an organophosphate pesticide commercially known as Malathion. The chemical substance is spread using motorized back atomizers, generating a moderate level of noise of 86 dBA when operated, which corresponds to their daily occupational exposure. In addition to hearing protection equipment, all NPG participants (100%) make use of other protection equipment, such as masks, pants, capes, boots, gloves, helmets, goggles. The CG was composed of 30 participants who were not exposed to noise or pesticides. All participants underwent Transient Evoked Otoacoustic Emissions (TEOAE) and Distortion Product Otoacoustic Emissions (DPOAE) assessments and a measure of the suppression effect which allowed examining the integrity of the medial olivocochlear efferent system. Student's t test and Fisher's test were applied to analyze the variability among TEOAE, DPOAE, and suppression effect averages between the NPG and the CG. The findings revealed significant differences for the TEOAE and DPOAE measures between NPG and CG groups. Workers in the NPG showed a reduced signal to noise ratio in both TEOAE and DPOAE measurements. A smaller general response level and a lower suppression value were also observed in the NPG. These findings suggest that chronic combined exposure to pesticides and noise may have altered the auditory function at the level of the medial olivocochlear efferent system. doi:10.1016/j.ntt.2015.04.077
123
NTX72 Assessment of the short-term neurobehavioral toxicity of a perinatal exposure to the hexabromocyclododecane (HBCDD) α-isomer in rats Nicolas Mauricea, Jean-Charles Olrya, Ronan Carioub, Philippe Marchandb, Gaud Dervilly-Pinelb, Bruno Le Bizecb, Angélique Travelc, Catherine Jondrevillea, Henri Schroedera a Université de Lorraine, Vandoeuvre-lès-Nancy, France b LUNAM Université, Nantes, France c ITAVI, Centre INRA de Tours, Nouzilly, France The present study aimed to investigate the developmental neurotoxicity of an early exposure to a-HBCDD through the ingestion of contaminated hen's egg in pregnant and lactating Wistar female rats. Eggs were obtained from hens after 3 months of daily feeding with a-HBCDD-contaminated feed at two levels of exposure, resulting in a content of a-HBCDD within the eggs of 30 and 100 ng/g of lipids, respectively. Female rats were daily administered p.o. with an appropriate volume of the whole egg from the day of fertilization (GD0) to the weaning day for pups (PND21). Thus, fetuses and pups were continuously exposed to HBCDD through the dam over a whole 42-day period including both gestation and lactation. Neurobehavioral development of pups was investigated from PND3 to PND 25 using various tasks including the righting reflex (PND3–5), the grasping reflex (PND4–6), the negative geotaxis (PND8–10) and the locomotor coordination test (PND19–21). Ultrasonic vocalizations of pups were also daily recorded from PND4 to PND16. After weaning, spontaneous motor activity and anxiety-related behavior were examined at PND25 in the open-field and in the elevated-plus maze, respectively. Present results showed a significant decrease in body weight of both pups exposed to the lower HBCDD level from PND3 to PND25, whereas the weight of rat pups exposed to 100 ng/g of HBCDD was not different from controls. During the first 3 weeks of life, impairments in the motor maturation of pups were observed in a dose-dependent manner depending on the test, whereas no significant differences were reported between male and female pups. At PND25, the anxiety level of female rats exposed to the lowest dose of HBCDD (30 ng/g) was significantly reduced whereas it remained unchanged in males. No significant variations were measured in rats exposed to the higher level of HBCD (100 ng/g). These results suggest the potent developmental neurotoxicity of an early chronic exposure to the HBCDD α-isomer through the ingestion of hen's eggs contaminated with this pollutant and question the long-lasting consequences of this exposure on behavior abilities and brain functioning in adulthood. doi:10.1016/j.ntt.2015.04.078
NTX73 Role of opioids in hemin-induced neurotoxicity Hannah Mick, Shekher Mohan Marshall University, School of Pharmacy, Huntington, WV, USA Background: Intracerebral hemorrhagic (ICH) stroke is defined by the rupture of intracranial artery that leads to the formation of a hematoma. Neuronal damage is associated with the lysis of red blood cells, which releases hemoglobin. Hemoglobin and its breakdown product hemin are neurotoxic. Increasing evidence suggests that drug abuse in the form of opioids can precede and contribute to the pathology of ICH brain injury. The role of opioids and their cognate receptors in hemin-induced neurotoxicity remains unclear. Hypothesis: We hypothesize that morphine may exacerbate and naltrexone may protect against hemin-induced toxicity.