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ABSTRACT: The aim of the present study was to compare the response to sub-chronic application of methamphetamine (MA) in adulthood in male and female rats prenatally exposed to the same drug. The spontaneous locomotor activity and exploratory behavior of adult male and female rats prenatally exposed to 5 mg/kg MA or saline (SAL) were tested in a Laboras apparatus (Metris B.V., Netherlands) for five consecutive days, 1 hr daily. MA 1 mg/kg or SAL were used as a challenge prior to testing. Our results showed that rats prenatally exposed to MA were more sensitive to sub-chronic administration of MA in adulthood than prenatally SAL-exposed rats. However, this sensitizing effect of prenatal MA exposure was manifested differently in males and females. In contrast, prenatal MA exposure decreased baseline locomotion in females. This study indicates that gender plays an important role in the sensitivity to MA during prenatal development and in adulthood. © 2012 Wiley Periodicals, Inc. Dev Psychobiol.
Developmental Psychobiology 02/2012; · 2.98 Impact Factor
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ABSTRACT: Our previous study showed that single injection of methamphetamine decreases social interaction (SI) in a dose-dependent manner that was further affected by stressful environment conditions. The aim of this study was to examine the effect of methamphetamine and its interaction with gonadal hormones on SI. Adult male and female rats were gonadectomized and assigned to testosterone-treated and oil-treated groups in male rats and estradiol-treated and oil-treated groups in female rats, respectively. Hormones were administered 30 min before each habituation in the open field. All four hormonal groups were further divided to control (without injection), saline (1 ml/kg saline injection), and methamphetamine (1 mg/kg) groups. Injections were applied 30 min before the SI test. The total duration and the total number of SI and nonsocial behavioral patterns were assessed. This study showed that an acute methamphetamine administration in a dose of 1 mg/kg decreased different types of SI in both sexes. In contrast, the same dose of methamphetamine increased locomotion and rearing behavior in male and female rats. The frequency and/or duration of SI (especially mutual sniffing and allogrooming) was lower in adult female rats relative to gonadectomized male rats, but locomotion was increased in female relative to male rats regardless of the presence or absence of gonadal hormones. In conclusion, this study is novel especially because it examines SI in both sexes in relation to the presence or absence of gonadal hormones.
Behavioural pharmacology 10/2011; 22(7):617-23. · 2.85 Impact Factor
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ABSTRACT: Methamphetamine (MA) is one of the most frequently used illicit drugs worldwide and also one of the most common drugs abused by pregnant women. Repeated administration of psychostimulants induces behavioral sensitization in response to treatment of the same or related drugs in rodents. The effect of prenatal MA exposure on sensitivity to drugs in adulthood is not yet fully determined. Because our most recent studies demonstrated that prenatal MA (5mg/kg) exposure makes adult rats more sensitive to acute injection of the same drug, we were interested whether the increased sensitivity corresponds with the increased drug-seeking behavior. The aim of the present study was to examine the effect of prenatal MA exposure on drug-seeking behavior of adult male rats tested in the conditioned place preference (CPP). The following psychostimulant drugs were used as a challenge in adulthood: MA (5mg/kg), amphetamine (5mg/kg) and cocaine (10mg/kg). All psychostimulant drugs induced increased drug-seeking behavior in adult male rats. However, while MA and amphetamine-induced increase in drug-seeking behavior did not differ based on the prenatal drug exposure, prenatally MA-exposed rats displayed tolerance effect to cocaine in adulthood. In addition, prenatally MA-exposed rats had decreased weight gain after administration of MA or amphetamine, while the weight of prenatally MA-exposed rats stayed unchanged after cocaine administration. Defecation was increased by all the drugs (MA, amphetamine and cocaine), while only amphetamine increased the tail temperature. In conclusion, our results did not confirm our hypothesis that prenatal MA exposure increases drug-seeking behavior in adulthood in the CPP test.
Behavioural brain research 05/2011; 224(1):80-6. · 3.22 Impact Factor
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ABSTRACT: The effect of psychostimulants on social behavior still remains unclear. Therefore the aim of the present study was to assess the effect of low doses of methamphetamine (MA) on social interaction (SI) in adult male rats. Rats were tested in three environmental conditions: (1) dimly lit, familiar environment, (2) dimly lit, unfamiliar environment and (3) intensely lit, unfamiliar environment considered to be low, middle and high stress, respectively. In each condition different set of animals was used. Rats were always divided into five groups. Control (without injection), saline (with 1 ml/kg saline injection) and three MA groups (doses: 0.5, 1 and 1.5mg/kg). Injections were applied 30 min prior to testing. Always a pair of unfamiliar rats of the same treatment group was tested. Their behavior was video recorded for 5 min in an open field. Times spent by SI (following, climbing, genital investigation, etc.) and non-social behavior (locomotion, rearing) were analyzed using a two-way ANOVA (drug treatment x stress condition). Our data demonstrate that all doses of MA, reduced SI. In addition, the unfamiliarity of the arena increased exploratory behavior (locomotion and rearing) in all treatment groups, while the SI was affected by the environmental condition only in controls or saline-treated rats, but not in MA-treated groups. In conclusion, our data demonstrate that MA administration impairs SI in dose- and stress condition-specific manner, however, some of our results may be due to increase locomotion and rearing induced by MA.
Behavioural brain research 12/2010; 214(2):423-7. · 3.22 Impact Factor
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ABSTRACT: The aim of the present study was to determine effects of methamphetamine (MA) exposure and cross-fostering on thermal nociceptive thresholds in different estrous phases in adult female rats. Rat mothers were exposed daily to injection of MA (5 mg/kg) or saline for 9 weeks: prior to impregnation, throughout gestation and lactation periods. Dams without any injections were used as an absolute control. On postnatal day 1, pups were cross-fostered so that each mother raised four pups of her own and eight pups from the mothers with the other two treatments. Offspring females were tested in adulthood (85–90 days) for thermal nociception as latency [s] of withdrawal reaction of forelimbs, hind limbs, and tail. Our results showed that prenatal MA exposure did not affect the nociception in adulthood, while postnatal MA exposure (i.e., MA administration to lactating mothers) had pro-nociceptive effects. The effect of postnatal MA exposure was apparent in both, fore- and hind limbs, while the latency to tail withdrawal reaction was the same among the groups. In addition, the pro-nociceptive effect of postnatal MA exposure did not depend on estrous cycle. This study indicates that postnatal but not prenatal exposure to MA affects nociception in adult female rats. However, it is still not clear whether the pro-nociceptive effect of postnatal MA exposure is linked to direct action of MA on neuronal organization, or to indirect action of MA mediated by impaired maternal care. © 2009 Wiley Periodicals, Inc. Dev Psychobiol 52: 71–77, 2010
Developmental Psychobiology 12/2009; 52(1):71 - 77. · 2.98 Impact Factor
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ABSTRACT: The aim of the present study was to determine effects of methamphetamine (MA) exposure and cross-fostering on thermal nociceptive thresholds in different estrous phases in adult female rats. Rat mothers were exposed daily to injection of MA (5 mg/kg) or saline for 9 weeks: prior to impregnation, throughout gestation and lactation periods. Dams without any injections were used as an absolute control. On postnatal day 1, pups were cross-fostered so that each mother raised four pups of her own and eight pups from the mothers with the other two treatments. Offspring females were tested in adulthood (85-90 days) for thermal nociception as latency [s] of withdrawal reaction of forelimbs, hind limbs, and tail. Our results showed that prenatal MA exposure did not affect the nociception in adulthood, while postnatal MA exposure (i.e., MA administration to lactating mothers) had pro-nociceptive effects. The effect of postnatal MA exposure was apparent in both, fore- and hind limbs, while the latency to tail withdrawal reaction was the same among the groups. In addition, the pro-nociceptive effect of postnatal MA exposure did not depend on estrous cycle. This study indicates that postnatal but not prenatal exposure to MA affects nociception in adult female rats. However, it is still not clear whether the pro-nociceptive effect of postnatal MA exposure is linked to direct action of MA on neuronal organization, or to indirect action of MA mediated by impaired maternal care.
Developmental Psychobiology 11/2009; 52(1):71-7. · 2.98 Impact Factor
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ABSTRACT: The aim of our study was to examine the effect of prenatal methamphetamine (MA) exposure and cross-fostering on cognitive functions of adult male rats tested in Morris water maze (MWM). Rat mothers were exposed daily to injection of MA (5mg/kg) or saline for 9 weeks: prior to impregnation, throughout gestation and lactation periods. Females without any injections were used as an absolute control. On postnatal day 1, pups were cross-fostered so that each mother raised 4 pups of her own and 8 pups from the mothers with the other two treatments. Four types of tests were used: (1) Place navigation test (Learning), (2) Probe test (Probe), (3) Retention memory test (Memory) and (4) Visible platform task. Our results demonstrate that the prenatal exposure to MA does not impact learning and memory, while postnatal exposure to MA shows impairments in cognition. In the test of learning, all animals fostered to MA-treated dams had longer latencies, bigger search error and used lower spatial strategies than the animals fostered to control or saline-treated mother, regardless of prenatal exposure. Regardless of postnatal exposure, the animals prenatally exposed to saline swam faster in all the tests than the animals prenatally exposed to MA and controls, respectively. This study indicates that postnatal but not prenatal exposure to MA affects learning in adult male rats. However, it is still not clear whether these impairments are due to a direct effect of MA on neuronal structure or due to an indirect effect of MA mediated by impaired maternal care.
Behavioural brain research 11/2009; 208(1):63-71. · 3.22 Impact Factor
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ABSTRACT: There are studies showing that drug abuse during pregnancy may have a long-term effect on progeny of drug-abusing mothers. Our previous work demonstrated that prenatal and/or postnatal methamphetamine injections impair maternal behavior. The purpose of the present study was to assess the effect of prenatal methamphetamine or stress exposure and postnatal breeding on postnatal development of rat pups. Female rats were injected with methamphetamine (5 mg/kg daily) or physiological saline prior, during and after gestation. Absolute controls did not receive any injections. On postnatal day 1, pups were cross-fostered so that each mother received some of her own and some of the pups from the mothers with the other two treatments. Pups were weighted daily for the entire lactation period. Postural motor reaction development was examined daily by righting reflex between postnatal day 1 and 12. On postnatal day 15 homing test examining pups' nest-seeking behavior was performed. On postnatal day 23 rotarod and bar-holding tests were used to investigate sensorimotor coordination of pups. We demonstrated that prenatal methamphetamine exposure impairs performance of sensorimotor tests (righting reflex on surface and rotarod test). Moreover, the effect of methamphetamine as well as the effect of prenatal stress induced by saline injections was affected by postnatal breeding conditions in sensorimotor tests as well as in the test of homing. Our results support the hypothesis that the variation in rat maternal care could serve as a mechanism for a nongenomic behavioral mode of transmission of traits.
International journal of developmental neuroscience: the official journal of the International Society for Developmental Neuroscience 01/2009; 27(2):149-55. · 2.03 Impact Factor
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ABSTRACT: The present study tested the hypothesis that cross-fostering influences the development of rat pups. Mothers were exposed daily to injection of methamphetamine (M) (5 mg/kg) or saline for 9 weeks: 3 weeks prior to impregnation, throughout gestation and lactation periods. Control females animals without any injections were used. On postnatal day (PD) 1, pups were cross-fostered so that each mother received four pups of her own and eight pups from the mothers with the other two treatments. Offspring were tested for sensorimotor development in preweaning period by using tests of: negative geotaxis, tail pull, righting reflexes, rotarod and bar-holding. Further, the pups were weighed daily. Our results showed that birth weight in prenatally M-exposed pups was lower than in control or saline-exposed pups. Prenatally M-exposed pups gained less weight than control or saline-exposed pups regardless of postnatal treatment and sex. Further, our data demonstrated that prenatal and postnatal M exposure impairs sensorimotor functions in most of the tests. On the other hand, the negative effect of prenatal M exposure was partially suppressed in prenatally M-exposed pups by cross-fostering to control dams. Our hypothesis that cross-fostering may affect postnatal development of pups was confirmed. © 2008 Wiley Periodicals, Inc. Dev Psychobiol 51: 73–83, 2009
Developmental Psychobiology 12/2008; 51(1):73 - 83. · 2.98 Impact Factor
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ABSTRACT: The present study tested the hypothesis that cross-fostering influences the development of rat pups. Mothers were exposed daily to injection of methamphetamine (M) (5 mg/kg) or saline for 9 weeks: 3 weeks prior to impregnation, throughout gestation and lactation periods. Control females animals without any injections were used. On postnatal day (PD) 1, pups were cross-fostered so that each mother received four pups of her own and eight pups from the mothers with the other two treatments. Offspring were tested for sensorimotor development in preweaning period by using tests of: negative geotaxis, tail pull, righting reflexes, rotarod and bar-holding. Further, the pups were weighed daily. Our results showed that birth weight in prenatally M-exposed pups was lower than in control or saline-exposed pups. Prenatally M-exposed pups gained less weight than control or saline-exposed pups regardless of postnatal treatment and sex. Further, our data demonstrated that prenatal and postnatal M exposure impairs sensorimotor functions in most of the tests. On the other hand, the negative effect of prenatal M exposure was partially suppressed in prenatally M-exposed pups by cross-fostering to control dams. Our hypothesis that cross-fostering may affect postnatal development of pups was confirmed.
Developmental Psychobiology 11/2008; 51(1):73-83. · 2.98 Impact Factor
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[show abstract]
[hide abstract]
ABSTRACT: There are studies showing that drug abuse during pregnancy may have a long-term effect on progeny of drug-abusing mothers. Our previous work demonstrated that prenatal and/or postnatal methamphetamine injections impair maternal behavior. The purpose of the present study was to assess the effect of prenatal methamphetamine or stress exposure and postnatal breeding on postnatal development of rat pups. Female rats were injected with methamphetamine (5 mg/kg daily) or physiological saline prior, during and after gestation. Absolute controls did not receive any injections. On postnatal day 1, pups were cross-fostered so that each mother received some of her own and some of the pups from the mothers with the other two treatments. Pups were weighted daily for the entire lactation period. Postural motor reaction development was examined daily by righting reflex between postnatal day 1 and 12. On postnatal day 15 homing test examining pups’ nest-seeking behavior was performed. On postnatal day 23 rotarod and bar-holding tests were used to investigate sensorimotor coordination of pups. We demonstrated that prenatal methamphetamine exposure impairs performance of sensorimotor tests (righting reflex on surface and rotarod test). Moreover, the effect of methamphetamine as well as the effect of prenatal stress induced by saline injections was affected by postnatal breeding conditions in sensorimotor tests as well as in the test of homing. Our results support the hypothesis that the variation in rat maternal care could serve as a mechanism for a nongenomic behavioral mode of transmission of traits.
International Journal of Developmental Neuroscience.
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[show abstract]
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ABSTRACT: The aim of our study was to examine the effect of prenatal methamphetamine (MA) exposure and cross-fostering on cognitive functions of adult male rats tested in Morris water maze (MWM). Rat mothers were exposed daily to injection of MA (5 mg/kg) or saline for 9 weeks: prior to impregnation, throughout gestation and lactation periods. Females without any injections were used as an absolute control. On postnatal day 1, pups were cross-fostered so that each mother raised 4 pups of her own and 8 pups from the mothers with the other two treatments. Four types of tests were used: (1) Place navigation test (Learning), (2) Probe test (Probe), (3) Retention memory test (Memory) and (4) Visible platform task. Our results demonstrate that the prenatal exposure to MA does not impact learning and memory, while postnatal exposure to MA shows impairments in cognition. In the test of learning, all animals fostered to MA-treated dams had longer latencies, bigger search error and used lower spatial strategies than the animals fostered to control or saline-treated mother, regardless of prenatal exposure. Regardless of postnatal exposure, the animals prenatally exposed to saline swam faster in all the tests than the animals prenatally exposed to MA and controls, respectively. This study indicates that postnatal but not prenatal exposure to MA affects learning in adult male rats. However, it is still not clear whether these impairments are due to a direct effect of MA on neuronal structure or due to an indirect effect of MA mediated by impaired maternal care.
Behavioural Brain Research.
