Reproductive Toxicology 20 (2005) 103–110

Maternal behavior is impaired by methamphetamine administeredduring pre-mating, gestation and lactation

RomanaSlamberova∗, Petra Charousova, Marie PometlovaDepartment of Normal, Pathological and Clinical Physiology, 3rd Faculty of Medicine, Charles University,

Ke Karlovu 4, 12000 Prague 2, Czech Republic

Received 22 June 2004; received in revised form 18 August 2004; accepted 26 November 2004Available online 29 December 2004

Abstract

Previous studies demonstrated that stimulant drugs, such as cocaine or amphetamine, administered during gestation or lactation mayattenuate maternal behavior in rats. The effect of methamphetamine (MA), a drug whose usage has increased lately, on maternal behaviorhas not yet been investigated. The present study tested the effect of MA (5 mg/kg daily) administered prior to, during and after gestationon maternal behavior. Regularity of the estrous cycle, the incidence of impregnation, and the weight gain was compared between groups( he mothera day. In theO ed changesi n-maternala controls. Int pups intot ted motherss onstrates an vior towardp©

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control, saline- and MA-treated). Maternal behavior was examined using two tests: Observation test (without disturbance of tnd pups) and Retrieval test (with short separation of pups from the mother). All tests were conducted prior to dosing eachbservation test, MA decreased the blanket position of active nursing, while increasing passive nursing. There were no MA-induc

n other maternal activities such as mother being in the nest, in contact with pups, or grooming pups. MA increased some noctivities, such as drinking, eating, and sleeping, while decreasing stereotypic behavior (sniffing and rearing) when compared to

he Retrieval test, MA-treated mothers were slower in retrieving the first pup, returning the first pup into the nest, and returning allhe nest. Interestingly, there were differences in maternal behavior also in saline-treated mothers relative to controls. Saline-treapent more time in the nest and groomed pups more than controls or MA-treated mothers. In conclusion, the present study demovel finding that MA administered during pre-mating, gestational and lactational periods has a negative effect on maternal behaups.2004 Elsevier Inc. All rights reserved.

eywords:Methamphetamine; Pregnancy; Lactation; Maternal behavior; Nursing; Retrieval test

. Introduction

Several studies[1–5] showed that stimulants such as co-aine and amphetamine injected during gestational or lac-ational periods may disrupt maternal behavior; however,he data regarding cocaine’s effect are very inconsistent.

hereas cocaine altered maternal behavior when injecteduring lactation[1,3,5], contradictory results have been re-orted on the effects of cocaine administered during ges-

ation. These range from impairments[6], minimal neg-tive effects[7], no effects[5], or even positive effects

∗ Corresponding author. Tel.: +420 224923241; fax: +420 224916896.E-mail address:rslamber@lf3.cuni.cz (R.Slamberova).

[8] on postpartum maternal care. Specifically, while higdoses of cocaine such as 20 mg/kg[3], 25 mg/kg [7], or30 mg/kg [6] administered during gestation disrupted mternal behavior (i.e. crouching, nest-building, and puptrieval), lower doses (6.3 or 13 mg/kg) did not affect manal behavior[7]. Furthermore, Peeke et al.[8] demonstratethat cocaine (50 mg/kg) increases nursing behavior inmothers.

Only two studies are available regarding the effectamphetamine administered during lactation on maternahavior. Amphetamine injected several times during thetation period disrupted the mother–pup inter-contact inval, retrieval latency, inter-retrieval interval, number of pretrieved, and number of corners to which the pups w

890-6238/$ – see front matter © 2004 Elsevier Inc. All rights reserved.oi:10.1016/j.reprotox.2004.11.010

104 R.Slamberov´a et al. / Reproductive Toxicology 20 (2005) 103–110

retrieved. It also impaired the time of nest building, nursing,and time of motion of the mothers[4]. Similarly, Frankova[2]demonstrated that mothers treated with amphetamine duringthe first 10 days of lactation had decreased latencies in theretrieval test and other maternal activities such as interactionwith pups, grooming pups, or nest building.

To the best of our knowledge, there are no similar kinds ofstudies on methamphetamine (MA), a drug whose usage hasincreased lately. The mechanism(s) of action of MA differsfrom amphetamine[9]. Whereas MA releases dopamine andserotonin equally, amphetamine is more specific to dopamine[9]. Because of their differing effects on dopamine and sero-tonin systems these drugs might be expected to produce dif-ferent effects on maternal behavior as well.

Clinical evidence suggests that during pregnancy womenmay replace other drugs with MA because it decreases ap-petite and therefore helps them to control weight while in-creasing energy[10]. Statistics show that only 17% of femaledrug abusers in the USA were primary MA users, but 38%had used it during pregnancy[10]. The impact of MA on themother and her child is, therefore, an important issue; how-ever, this research is still at its beginning and the findings areinconclusive.

Some studies showed that repeated administration ofhigher doses (50 mg/kg) of MA to pregnant rats resulted inhigh incidence rates of delivery failure and maternal deathr hl tiontp tion( tiont Re-t er).Mh find-i ea un-p otypicb MAa 5o entsr oxi-m busedM

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2.2. Injection and determination of the estrous cycle

One week after arrival, females were randomly assignedto MA-treated, saline-treated, or control groups. MA was in-jected daily subcutaneously (s.c.) at a dose of 5 mg/kg forapproximately nine weeks: about three weeks prior to impreg-nation, through the entire gestation period and for 22 days oflactation. The concentration of solution was 10 mg/ml suchthat each animal received 0.5 ml/kg body weight. Saline wasinjected s.c. at the same time and volume as MA. Controlfemales did not receive any injection. For three weeks priorto impregnation, all females were weighed daily and checkedby vaginal smear lavage to see whether or not MA altered theregularity and duration of the estrous cycle. The smear wasexamined by light microscopy using 20× magnification. Es-trous cycles were considered regular if they were of 4–5 daysduration regularly repeated across a period of 3 weeks. Es-trous cycles were considered irregular if they were∼4 dayslong, but irregularly repeated in the period of 3 weeks, or ifthey were longer than 5 days[19].

2.3. Impregnation and delivery

At the onset of the estrus phase of the estrous cycle af-ter the first three weeks of injection[20] female rats wereh e ando eareda revi-o ation.M werew , fe-m intom the2 ationp

(PD)0 alesa d be-t t eachm fromt n forc ccep-t s andc up( st int sedp thel d fori oed.T hen-e s wask witht . Thei reda

elative to controls[11]. Additionally, mothers injected witower doses of MA (1, 3, and 5 mg/kg) had shorter gestaimes and produced litters smaller than controls[12,13]. Theresent study investigated the effect of MA administra5 mg/kg daily) on maternal behaviors using the Observaest (without disturbance of the mother and pups) andrieval test (with short separation of pups from the mothodified methods as in our previous work[14,15] are usedere. The dose of 5 mg/kg was chosen based on the

ngs of Weissman and Caldecott-Hazard[16] that this dosltered locomotor and exploratory behaviors. Our ownublished observations demonstrated increased stereehavior of mothers that last for several hours afterpplication. Furthermore, studies[13,17,18]showed thatr 10 mg/kg MA administered to pregnant female rodesulted in fetal brain drug concentrations that apprate those reported in human infants whose mothers aA.

. Methods

.1. Housing

Thirty-five nulliparous adult female Wistar ra250–300 g) were purchased from Anlab farms (Prazech Republic). Animals were housed four to fiveage and acclimated for a week in a temperature-contr22–24◦C) colony room with food and water ad libitum12-h light/12-h dark cycle with lights on at 06:00 h.

oused overnight with sexually mature males (one femalne male per cage). The next morning females were smgain for the presence of sperm and returned to their pus home cage. This day was counted as day 1 of gestA injections continued as above and pregnant ratseighed daily during gestation. On day 21 of gestationales were removed from the group cages and placedaternity cages. Expected day of delivery in our colony is2nd day of gestation. There were no females with a gesteriod shorter than 22 days.

The day of delivery was counted as postpartum day. Number of pups in the litter and percentage of mnd females in each litter was recorded and compare

ween groups. On PD 1, pups were cross-fostered so thaother received some of her own and some of the pups

he mothers with the other two treatments. The reasoross-fostering was to see if there were differences in aance of the adopted pups between MA-treated motherontrol groups, and/or if MA treatment affected which pown or adoptive) a mother choose to pick up as the firhe Retrieval test (see the following for details). MA-expoups were injected intradermally with black India ink in

eft foot pad and saline-exposed pups in the right foot padentification. Pups from control mothers were not tattohe number of pups in each litter was adjusted to 10. Wver possible the same number of male and female pupept in each litter. Mothers (eight per treatment group)heir pups were tested in two series of maternal testsnjections of MA or saline, respectively, were administefter both tests ended.

R.Slamberov´a et al. / Reproductive Toxicology 20 (2005) 103–110 105

2.4. Observation test

Maternal behavior was observed daily for 50 min in thehome cage of each mother and her litter between PD 1 andPD 22. The time of observation was during the light phaseof the light/dark cycle, between 08:00 and 09:00 h. A similarmethod was used as in our previous studies[14,15]. Duringeach 50-min session, each mother and litter were observed10 times for 5 s at 5 min intervals. Eleven types of activitiesexhibited by the mother and three nursing positions (see thefollowing) were recorded during each session. Thus, eachmother and litter was observed 220 times (22 days× 10 ob-servations/session). During each observation “1” was givenif a behavior occurred and a “0” if it did not.

First, it was noted whether or not a mother was nurs-ing. Three different positions were recognized as nursing: (a)arched-nursing—when the mother was arched over her pupswith legs splayed; (b)blanket-nursing—when the motherwas over her litter but did not have her back arched andthere was no obvious extension of her legs; and (c)passive-nursing—when the mother was lying on her side or on herback with one or more suckling pups. The first two nursingpositions were designated as active nursing, and the third aspassive nursing. In addition to nursing, eleven other maternalactivities were recorded during each session: (1) mother in orout of the nest; (2) mother in contact with any of her pups; (3)m ups;( tingw ; (9)m ingw self-c therr

2

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newc atingp tirel agea otherw : (1)

latency to carry the first pup; (2) latency to return the first pupinto the nest; and (3) latency to return all pups into the nest.Any unusual behaviors were recorded, such as: (1) removinga previously returned pup from the nest; (2) intensive caringfor the pups around the cage before placing them in the nest;and (3) extensive disruption of the nest shavings. During eachobservation “1” was given if a behavior occurred and a “0” ifit did not. It was also noted whether a mother carried one ofher own pups or one of the adopted pups into the nest first.

2.6. Data analysis

The incidence of regular or irregular estrous cycle and theincidence of successful and/or healthy pregnancy were ana-lyzed byχ2 test. The weight changes during the three weeksof injections prior to impregnation and the weight gainedduring the gestation period were analyzed using a one-wayANOVA (drug treatment). One-way ANOVA (prenatal drugexposure) was conducted to analyze the number of pups ineach litter and the percentage of males and females in eachlitter. In the Observation test, the occurrence of each activity(maximum 10 in each session) was counted in each of 22 ses-sions. All activities were tested using one-way ANOVA (drugtreatment) with Repeated Measure (22 days of testing). In theRetrieval test, latencies were analyzed by one-way ANOVA(drug treatment) with Repeated Measure (12 days of test-i f hero yt ns inA nt ift

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other grooming any of her pups; (4) mother carrying p5) mother manipulating nest shavings; (6) mother resith eyes closed; (7) mother eating; (8) mother drinkingother self-grooming [eating, drinking and self-groomere also counted together as a single measure ofare]; (10) mother sniffing with head raised; and (11) moearing.

.5. Retrieval test

The same mothers and pups were tested for Retrievalways after the Observation test ended. The retrieval tesonducted daily between PD 1 and PD 12 between 09:00:00 h so each mother and litter was tested 12 timesame method was used as in our previous studies[14,15].

All pups were separated from their mothers into aage for 5 min. The cage with pups was placed on a head to prevent chilling. After this brief separation, the en

itter was returned to their mothers into the maternity cnd the pups were spread all around the cage. The mas then observed for 10 min for the following measures

able 1ffects of MA administration on estrous cycle and litter sizes

Estrous cycle (n= 10–15)

Regular/irregular (number of females) Days in o

ontrol 10/0 4± 0.15aline 7/3 4± 0.75A 0/15 5± 0.63

alues are mean± S.E.M.

ng). The incidence of whether the mother carried one own or an adopted pup first to the nest was analyzed bχ2

est. Bonferroni test was used for post hoc comparisoNOVA analyses. Differences were considered significa

he alpha level,P< 0.05.

. Results

.1. Estrous cycle and weight prior to impregnation

There was a significant difference between groups inegularity of the estrous cycle. While all control females wycling regularly, saline females cycled irregularly in 3ases and the MA-treated females in 100% cases (Table 1).s shown inFig. 1, there were differences in weight gain d

ng the pre-mating period between groups [F(2, 32) = 4.94< 0.01]. MA-treated females prior to impregnation didain any weight and some females even lost some wuring the three weeks of injection prior to impregnationontrast, the control females gained on average around

Litters (n= 8)

le (average) Males (average in litter) Females (averag

7± 0.8 6± 1.15± 0.7 7± 0.96± 0.8 6± 1.0

106 R.Slamberov´a et al. / Reproductive Toxicology 20 (2005) 103–110

Fig. 1. Effect of MA administration on weight gain during the pre-mating period. Values are means± S.E.M. (n= 8) in 21 days before impregnation (n= 10–15).[F(2, 32) = 4.94,*P< 0.01]; control > saline or MA.

and the saline-treated females around 10 g for the same timeperiod.

3.2. Pregnancy and weight gain

The incidence of successful and/or a healthy pregnancydid not significantly differ between groups; however, therewas a tendency toward a lower incidence of successful deliv-ery for MA-treated mothers relative to both control groups.Successfully delivered included 8 of 10 controls, 8 of 10saline-treated rats, and 8 of 15 MA-treated rats. There wereno significant differences between groups in weight gainduring gestation. All groups regardless of treatment gained135–140 g during gestation. The length of gestation differedbetween groups [χ2 = 6.11;P< 0.05]. Seven of eight con-trol females, two of eight saline-treated females, and none ofeight MA-treated females had gestation periods of 22 days.The length of gestation for other females was 23 days and inone MA- and two saline-treated females as much as 24 days.There were no drug-induced differences in litter sizes or inthe percentage of males and females in litters (Table 1).

3.3. Observation test

MA-treated and saline-treated mothers [F(2, 21) = 5.88,P n ofa d,M nurs-i edf ing( umt ,P4 urs-i psr

Fig. 2. Effects of MA administration on nursing score in Observation test.Values are presented as averages for all 22 sessions (means± S.E.M.;n= 8).(A) Arched position of active nursing, (B) blanket position of active nursing,(C) passive nursing.*P< 0.01 vs. control;+P< 0.05 vs. saline (ANOVA;Bonferroni post hoc test).

< 0.01] generally nursed less by the blanket positioctive nursing (Fig. 2B) than controls. On the other hanA-treated mothers had a higher incidence of passive

ng [F(2, 21) = 5.57,P< 0.05] than control or saline-treatemale rats (Fig. 2C). The arched position of active nursFig. 2A) did not differ between groups. As the postpartime progressed, both the arched position [F(21, 441) = 8.23< 0.0001] and the blanket position of active nursing [F(21,41) = 3.23,P< 0.0001] decreased, while the passive n

ng [F(21, 441) = 5.34,P< 0.0001] increased in all grouegardless of the drug treatment (data not shown).

R.Slamberov´a et al. / Reproductive Toxicology 20 (2005) 103–110 107

Table 2Effects of MA administration on maternal and non-maternal activities of rats

Control Saline MA

Maternal activitiesIn the nest 6.93± 0.33 5.53± 0.33** 6.13± 0.28In contact with

pups7.43± 0.32 6.56± 0.30 6.88± 0.27

Grooming pups 0.73± 0.12 1.10± 0.19* 0.61± 0.11++

Carrying pups NA NA NAManipulating nest

shavingsNA NA NA

Non-maternal activitiesSelf-care 1.39± 0.19 0.57± 0.20 0.45± 0.16Eating 0.55± 0.11 0.81± 0.12 1.10± 0.11*

Drinking 0.23± 0.07 0.48± 0.80* 0.57± 0.07**

Self-grooming 0.39± 0.07 0.57± 0.10 0.45± 0.07Resting with eyes

closed2.59± 0.23 1.99± 0.20 3.70± 0.18*,++

Rearing 0.70± 0.14 0.88± 0.15 0.28± 0.05**,+++

Sniffing 0.90± 0.14 1.38± 0.15* 0.33± 0.07**,+++

Values are averages from all 22 days of testing (mean± S.E.M.);n= 8. NA:not analyzed measures (low incidence of these activities could not be ana-lyzed by the one-way ANOVA with repeated measure).

∗ P< 0.05 vs. control.∗∗ P< 0.01 vs. control.

++ P< 0.01 vs. saline (ANOVA).+++P< 0.0001 vs. saline (ANOVA).

There were no differences induced by MA treatment inother maternal activities such as mothers being in the nest, incontact with their pups, or grooming pups relative to controls(Table 2). Interestingly, saline-treated mothers were less of-ten in the nest [F(2, 21) = 4.95,P< 0.05] than controls andgroomed the pups more [F(2, 21) = 4.58,P< 0.05] than con-trols or MA-treated mothers (Table 2). Additionally, mothers,regardless of their drug treatment, were less often in the nest[F(21, 441) = 6.52,P< 0.0001], in contact with their pups[F(21, 441) = 4.31,P< 0.0001], and grooming pups [F(21,441) = 5.4,P< 0.0001] as the postpartum time progressed(data not shown). The incidence of mothers carrying the pupsor manipulating the shavings during the sessions was too lowfor statistical analysis.

When non-maternal activities were compared (Table 2),MA-treated and saline-treated mothers drank more than con-trols [F(2, 21) = 4.57,P< 0.05]. Eating was increased inMA-treated mothers relative to controls [F(2, 21) = 3.99,P< 0.05]. Furthermore, sleeping increased in MA-treatedmothers relative to control and saline-treated mothers [F(2,21) = 6.94,P< 0.01]. As the postpartum time progressed,mothers regardless of their treatment exhibited more drinking[F(21, 441) = 3.61,P< 0.0001] and eating [F(21, 441) = 4.76,P< 0.0001] (data not shown). Self-grooming, sleeping andthe total self-care did not change during the 22 days of theexperiment.

a edi e-t dis-p tivi-

ties did not change as the postpartum time progressed(data not shown).

3.4. Retrieval test

Pregnant dams treated with MA showed increased latencyto carry the first pup [F(2, 21) = 12.93,P< 0.001] (Fig. 3A),to return the first pup [F(2, 21) = 14.57,P< 0.001] (Fig. 3B),and to return all pups into the nest [F(2, 21) = 14.3,P< 0.001](Fig. 3C) relative to control or saline-treated female rats.There was an interaction between drug treatment and post-partum days in the latency to carry the first pup [F(11,231) = 2.32,P< 0.01] (Fig. 3A) and to return the first pupinto the nest [F(11, 231) = 1.66,P< 0.05] (Fig. 3B). Whereaslatencies did not change in control or saline-treated femalesas postpartum time advanced, the latencies increased in MA-treated dams. There was no interaction between drug treat-

Fig. 3. Effects of MA administration on the latencies in Retrieval test. Valuesare means± S.E.M. (n= 8) in all 12 sessions. (A) Latency to carry firstpup, (B) latency to return first pup into the nest, (C) latency to return allpups into the nest. (A and B)*P< 0.001 vs. control and saline at the samepostpartum day (Bonferroni post hoc test). (C) Main effect of drug treatmentin all measures (ANOVA).*P< 0.001 vs. control and saline regardless of thepostpartum day (Bonferroni post hoc test).

As shown inTable 2, sniffing [F(2, 21) = 14.57,P< 0.001]nd rearing [F(2, 21) = 13.65,P< 0.001] were decreas

n MA-treated mothers relative to control or salinreated females. Additionally, saline-treated motherslayed even more rearing than controls. These ac

108 R.Slamberov´a et al. / Reproductive Toxicology 20 (2005) 103–110

ment and postpartum days in the latency to return all pupsinto the nest. MA-treated mothers were slower in returningall pups during the entire postpartum time period of the Re-trieval test (Fig. 3C). No unusual behaviors, as defined in theSection2, were exhibited by any of the mothers during the 12days of testing. Even the incidence of whether the first pupcarried into the nest was their own or adopted did not differbetween mothers of different treatment groups.

4. Discussion

The finding that repeated MA administration impairs es-trous cycle and weight gain prior to impregnation is in agree-ment with other studies[21]. In contrast to the work of Mar-tin et al. [12,13] showing a shorter gestation period in MA-treated mother, we observed a longer gestation period in MA-treated mothers relative to controls. Neither did we observethe reported decrease in weight gain during gestation[12,13].The reason why we did not see the negative effect of MA onlength of gestation or weight gain during gestation might bedue to different frequencies of injection. We injected 5 mg/kgof MA once daily whereas Martin et al.[12,13]used the samedose administered twice daily.

Our data demonstrate that MA exposure decreased theblanket position of active nursing and pup retrieval, but didn r be-i ups.T wingt fore,w tim-u com-p teda cta-t man-n inter-c d in-c hicht rsingt

s ofc min-id g/kg)d ost-p cy toc chingd ingp eensd cor-r main-t es inm ,K in-j ased

retrieving, grouping, and crouching over six pups). Thesefindings reported here, together with other studies[1–4,6]indicate that MA disrupts maternal behavior similarly to am-phetamine and cocaine.

Why MA-treated mothers showed less maternal behav-ior toward their pups is, however, not yet clear. MA admin-istration alters the dopaminergic and serotonergic systems[22–24]among brain regions involved in maternal behavior,such as the amygdala and/or the nucleus accumbens[25,26].Therefore, it is possible that alterations to these systems maycontribute to the increased maternal activities of MA-treatedfemale rats shown here. The effect of chronic MA treatmenton dopaminergic and serotonergic systems in the preopticarea, another important brain region in nursing and mater-nal behavior[25,26], was not investigated. This might bepart of a future goal to clarify the mechanism(s) of the effectof MA on maternal behavior. Vernotica et al.[27] demon-strated that bilateral microinfusion of cocaine (50�g/0.5�lper side), that affects the same neurotransmitter systems asMA [28], into the medial preoptic area or nucleus accum-bens impairs maternal behavior. This supports our hypoth-esis that MA may affect dopaminergic and/or serotonergicsystems in a manner similar to cocaine for brain regions in-volved in maternal behavior. Furthermore, Elliott et al.[1]suggested that cocaine may disrupt maternal behavior andmaternal aggression through its action on the oxytocinergics edialp in oro there rnalb n thisp

e int MA-t inedb ringt ssed( thanu ctedt aveb ctions,w thatt rnalb nete s inM willb in allg

sentw pingr t inM ilart an-o ti iumi ac-

ot change other maternal activities such as the motheng in the nest, in contact with pups, and/or grooming po the best of our knowledge there are no studies shohe effects of MA treatment on maternal behavior. Theree can compare our results only to the effects of other slant drugs, such as amphetamine or cocaine. Whenared to amphetamine[2,4], it has been shown that repeamphetamine injection in several time periods during la

ion disrupted maternal behavior in a dose-dependenter. Specifically, amphetamine decreased mother–pupontact interval and the number of pups retrieved, anreased the retrieval latency and number of corners to whe pups were retrieved. The time of nest building and nuime is also decreased in their studies[2,4].

Our data corroborate the generally impaired effectocaine on maternal behavior reported for cocaine adstration during gestation or lactation[6]. Those authors[6]emonstrated that chronic cocaine administration (30 muring gestation day 8–20 delayed or diminished the partum onset of maternal behavior, increased the latenrouch over pups, and decreased the duration of crouuring a 30-min observation period immediately followarturition. Longer latencies to nest building have also bhown for cocaine-treated dams than saline controls[6]. Ad-itionally, acute cocaine administration during lactationelated with increases in the onset, and decreases inenance, of maternal behavior as well as with decreasaternal aggressive behavior in rat dams[1]. Furthermoreinsley et al.[3] demonstrate a disruption by cocaine,

ected during lactation, on full maternal behavior (decre

ystem, because cocaine alters oxytocin levels in the mreoptic area and amygdala. Thus, alterations of oxytocther hormones involved in reproduction might be anoxplanation for the effect of stimulant drugs on mateehavior. Future studies are necessary to shed light oroblem.

Interestingly, saline-treated mothers spent more timhe nest and groomed their pups more than controls orreated mothers. This unexpected finding might be explay the stressful effect of repeated saline injections du

he experimental treatment period. It is possible that streinjected) mothers were more concerned about their pupsninjected (unstressed) controls; however, MA was inje

he same way as saline, so the MA injections would heen expected to cause the same changes as saline injehich they did not. Alternatively, it might be speculated

he fear induced by injections and the impairment in mateehavior induced by MA contradict each other and theffect was no change in the above mentioned activitieA-treated mothers relative to controls. Future studiese needed to investigate the levels of stress hormonesroups of mothers to confirm or refute this hypothesis.

When comparing non-maternal activities, the preork demonstrated that MA increases drinking and slee

elative to control rats. It is possible that the former effecA-treated females is associated with hyponatremia, sim

o 3,4-methylenedioxymethylamphetamine (“Ecstasy”),ther drug of amphetamine group[29]. Future studies migh

nvestigate this hypothesis by analyzing the levels of sodn the blood of MA-treated rats. The sniffing and rearing

R. Slamberov´a et al. / Reproductive Toxicology 20 (2005) 103–110 109

tivities that might be defined as stereotypic behavior[30,31]were lowered in MA-treated mothers. This is of interest be-cause MA is known to increase stereotypic behavior[32];however, MA in the present study was administered oncedaily, after both experiments ended. The mothers displayedincreased stereotypic behavior a few minutes after injection(data not shown) as described in other studies[32]. Thus,it seems that MA increases stereotypic behavior only for alimited time after MA injection and not throughout the en-tire day. Moreover, the present study demonstrates that MA-treated mothers rested more with their eyes closed and thatmight also affect the lower incidence of stereotypic behaviorsof MA-treated mothers.

There is a steady decrease in active nursing and maternalactivities with the progression of postpartum period in bothexperiments. This may be explained by the maturation andincreased activity of pups during the third week of lactation.Pups are able to move around and suckle actively even if themother is not in the nest nursing and/or caring for them. Atthe same time there is an increase in non-maternal activitiesof mothers, such as eating, drinking, and resting with eyesclosed as postpartum day advances.

Taken together, the present study demonstrates that dailyMA administration prior to, during, and after gestation im-paired critical maternal behaviors. To the best of our knowl-edge this is the first study showing such an effect of MA anda s(s)o inf

A

003f oft cy oft 0005t u-c theiraZ andM e-d erer andU Gov-e re ofL onso o.3

R

ersctat-ernal–34.

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[4] Piccirillo M, Alpert JE, Cohen DJ, Shaywitz BA. Amphetamine andmaternal behavior: dose response relationships. Psychopharmacology(Berlin) 1980;70:195–9.

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[9] Sabol KE, Richards JB, Layton K, Seiden LS. Amphetamine analogshave differential effects on DRL 36-s schedule performance. Psy-chopharmacology (Berlin) 1995;121:57–65.

[10] Marwick C. NIDA seeking data on effect of fetal exposure tomethamphetamine. J Am Med Assoc 2000;283:2225–6.

[11] Acuff-Smith KD, George M, Lorens SA, Vorhees CV. Preliminaryevidence for methamphetamine-induced behavioral and ocular ef-fects in rat offspring following exposure during early organogenesis.Psychopharmacology 1992;109:255–63.

[12] Martin JC. Effects on offspring of chronic maternal metham-

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dds to similar studies with other drugs. The mechanismf action of MA on maternal behavior will be examined

uture studies.

cknowledgments

This study was supported by grants: # NF/7456-3/2rom the Internal Grant Agency of the Ministry of Healthhe Czech Republic, # 305/03/0774 from the Grant Agenhe Czech Republic, and Research Goal # MSM 11120o R.S., and by project # LN00B122 from Ministry of Edation, Youth and Sports to M.P. The authors expressppreciation to Jarmila Kourilova, Helena Smetanova, anduzana Jezdıkova for their excellent technical assistance,ichelle A. Riley for edition of the manuscript. The procures for animal experimentation utilized in this report weviewed and approved by the Institutional Animal Carese Committee and are in agreement with the Czechrnment Requirements under the Policy of Humans Caaboratory Animals (No. 246/1992) and with the regulatif the Ministry of Agriculture of the Czech Republic (N11/1997).

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