Effects of valproic acid on gene expression in the rhombencephalon of day 12 rat embryos

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biochemical effects are related to the different behavioral outcomes remains to be determined. Supported by NIH grants DA006733, DA021394, and DA014269. doi:10.1016/j.ntt.2007.03.047

NBTS 44 Cocaine's impact on reward, activity, and affect are dose-dependently impacted by age: adolescent versus adult exposure B. Kelly, A. Furr, A. Franchetti, C. Perry, H. Rohrer, H. Stanley, L. Anderson-Low, C. Huston, S. Ferland, T. Mitchem Bridgewater College, Bridgewater, VA, United States Recent research suggests that adolescent mice, compared with adults, show a reduced sensitivity to the reinforcing effects of abused drugs; such reductions are thought to elevate drug abuse risk. Behavioral pharmacological methods associated with affect and reward (forced swim test, FST; motor activity, MA; conditioned place preference, CPP) were used to examine changes in behavior and sensitivity to cocaine (0, 5, 10, and 20 mg/kg, between subject design, n = 12). Testing was performed on male adolescent (PND 25, N = 48) and adult mice (PND 85, N = 48). FSTs occurred for 6 min, across five daily sessions: habituation, saline, saline, cocaine and saline. Swimming, climbing, and immobility were recorded. After a 2day break, subjects were acclimated to the MA testing apparatus (4 days/saline); the MA effects of cocaine (30 min, cm traveled; 5, 10, 20, and 40 mg/kg, IP) were measured. Cocaine tests were preceded and followed by daily saline tests. Finally, mice underwent CPP testing. Cocaine was paired with the subject's non-preferred side, saline with the preferred side. Conditioning sessions were conducted for 8 days with a drug-free post-test occurring on the day following the final conditioning session. Consistent and significant differences were noted across age, with the adolescent subjects showing a more rapid despair response, elevated motor activity, and decreased conditioning to cocaine compared to controls. Supported by The Thomas F. Jeffress and Kate Miller Jeffress Memorial Trust.

Although studies to date largely have used retrospective measurement of prenatal exposure or clinically selected samples, prenatal tobacco exposure (PTE) appears to be a specific risk factor for externalizing symptomatology. Both smoking behavior and variations in attention and emotional modulation are heritable. Although clearly these behaviors are determined, at least in part, by multiple genes, DRD2 has been linked both to smoking behavior and to variations in behavior. Because prenatal nicotine exposure in non-human animals results in reductions in subcortical dopaminergic activity, the impact of PTE likely is exacerbated in those with specific genetic profiles. Participants (N = 170; half PTE) prospectively recruited during pregnancy (with biochemical verification of exposure status) were enrolled. Buccal cell samples were collected at birth and neonatal attention control and stress regulation were measured at 1 month. PTE infants were less responsive to auditory and visual stimuli and were more irritable both to moderately stressful and neutral stimuli, but not in soothability or maturity. While there was no difference in the genotype distribution by exposure group, DRD2 genotype was related to outcome. Infants who carried at least 1 copy of the A1 risk allele were more attentive to visual and auditory stimuli, and those who were exposed to tobacco prenatally were less responsive. In contrast, those with at least one copy of the DRD2 A1 allele or those who were exposed to tobacco prenatally were more irritable to stimuli than were non-exposed infants who did not carry the A1 allele. This preliminary neonatal pattern suggests that the relation between genotype, the prenatal environment and concomitant neuropathology, and its developmental expression in observed behavior is complicated. Carefully delineated longitudinal studies characterizing these specific pathways as they unfold across development are needed. Funded by R01 DA014661, R01 MH065668, HD038051, HD050309. doi:10.1016/j.ntt.2007.03.049

NBTS 46 Effects of valproic acid on gene expression in the rhombencephalon of day 12 rat embryos C.J. Stodgell, G. Glazko University of Rochester, Rochester, NY, United States

doi:10.1016/j.ntt.2007.03.048

NBTS 45 Gene–environment interaction: impact of prenatal tobacco exposure and the DRD2 gene on neonatal regulation K.A, Espy a, C. Stoppa, J. Huggenvikb, T. Jamesonb, D. Gilbert, S. Wiebea, P. Stewart b a University of Nebraska-Lincoln Lincoln, NE, United States b Southern Illinois University, Carbondale, Illinois, United States

Valproic acid (VPA) is a drug used for treating seizures, bipolar disorder, and migraines. VPA is a histone deacetylase (HDAC) inhibitor. It is also a potent teratogen. In utero exposure leads to stigmata including facial dysmorphology, neural tube defects, developmental delay, and increased risk for autism. Because of the physical defects seen in the brainstem and cerebellum, and the behavioral abnormalities seen after in utero exposure, we tested VPA's ability to alter gene expression in rhombencephalon — the anatomical antecedent for these regions. Gestational day 12, timed-pregnant Long Evans rats were treated by I.P. injection with either 3.6 mmol/kg VPA, 1.8 mmol/kg 4yn-VPA

Abstracts / Neurotoxicology and Teratology 29 (2007) 395–414

(a teratogenic form of VPA), or 3.6 mmol/kg isoethyl-butyl (IEVPA; a nonteratogenic form). As a vehicle control, we also exposed other dams to 1 ml/kg saline. Other treatments were also tested: .32 μg/kg trichostatin A (an HDAC inhibitor), or 60 mg/kg P.O. retinoic acid. After a 2-h exposure, the embryos were removed from the uterus, embedded in O.T.C. media and kept frozen at − 80 °C, until serially sectioned at 6 μM. Slices were mounted on glass slides and H & E stained. Rhombencephalon tissue was isolated by laser-capture microdissection. RNA was extracted from ca. 750–1000 cells of the rhombencephalon per embryo, and the mRNA isolated. Gene expression was determined by hybridizing the cRNA to Affymetrix Rat expression microarrays. Gene expression from the treatments was compared to saline. We selected differentially expressed genes (DEGs) by calculating a t-statistic and selecting the 50 smallest P-values for each comparison. Analyses revealed that many of the DEGs were involved in neuronal and angiogenic processes, confirming other reports of VPA's antiangiogenic properties. Expression profiles showed that some of the DEGs were only affected by 1 treatment and others by 2 or more, suggesting that these teratogens share some common pathways. Neuropillin-1 (Nrp-1), which is involved in neuronal development and angiogenesis, was decreased in the VPA group compared to saline. Genes downstream of Hoxa1 were also affected by VPA exposure (e.g., Nnt (↑), Hnf-3 (↓), Gbx2 (↑)), which further elucidates the mechanism of VPA's teratogenicity. doi:10.1016/j.ntt.2007.03.050

NBTS 47 Pharmacokinetics of psychotropic drugs in pregnancy D.K. Sit, J. M. Perel, J. Helsel, K.L. Wisner University of Pittsburgh, PA, United States Women of reproductive age are at high risk for major depressive disorder (MDD). The lifetime risk for women with MDD is 10– 25% with peak prevalence between 25 and 44 years. Antidepressant drug treatment is indicated for moderate to severe depression in pregnancy. Research on the pharmacokinetics (PK) is available on medical diseases and subpopulations of elderly. The need for similar studies in pregnancy is essential (www.fda.gov/cder/guidance/5917dft.htm). The number required for PK studies is far less than the number required for a prospective study of outcomes related to drug exposure. In our study on Antidepressant Drug Use in Pregnancy (PI: Dr. Wisner) we investigate outcomes of MDD and antidepressant drug use longitudinally in pregnancy and 2 years postpartum. In this sub-study we examine the steady state PK of the cytochrome 2C19 (decreases in pregnancy) substrates citalopram and escitalopram during pregnancy and the first months postpartum. Drug plasma samples are collected at 20, 30, 36 weeks gestation and delivery (cord), 2 and 12 weeks postpartum. Doses are charted across each week of gestation

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and postpartum and corroborated with the treating physician. Chiral drug levels are obtained within 1.5–2.0 times or more than the estimated half-lives to increase the precision of the terminal slopes. The drug dose data and plasma levels are used to calculate level-dose ratios. At each visit, we record exposures to other drugs, smoking by number of pack-weeks, and alcohol use by average daily volume. Women with active substance use are excluded. Lab Procedure. Chiral medication levels are analyzed for separate plasma bound and unbound drug in compliance with FDA recommendations in the experienced laboratory of James M. Perel, Ph.D., at the University of Pittsburgh. We present a case series of women who received citalopram monotherapy during pregnancy and postpartum. The level–dose ratios for R-citalopram, S-citalopram, R-desmethylcitalopram and S-desmethylcitalopram decreased at 30, 36 weeks gestation and delivery compared to 20 weeks gestation; the level–dose ratios for these substrates returned to first trimester ranges by 12 weeks postpartum. The level–dose ratio of R-citalopram exceeded by more than twice the ratios of the other 3 substrates. Although our data are not definitive, our cases illustrate the change in pharmacokinetics across pregnancy and postpartum. Important treatment implications must be considered. doi:10.1016/j.ntt.2007.03.051

NBTS 48 Association between antidepressant use during pregnancy and infants born small for gestational age É. Ramos a,b, D. Oraichi b, A. Bérard a,b a University of Montréal, Montréal, Québec, Canada b CHU Sainte-Justine, Montréal, Québec, Canada Previous studies have suggested an association between antidepressant use during pregnancy, prematurity, and low birth weight. Findings on trimester of exposure and class of antidepressant used have been contradictory. Furthermore, outcome measures combining birth weight and gestational age such as ‘Small for Gestational Age’ (SGA) has rarely been investigated. Therefore, our objective was to quantify the association between class of antidepressant use during pregnancy and infants being born SGA according to trimester of exposure. We performed a case–control study to assess whether having a newborn SGA is associated with exposure to antidepressants during pregnancy. Data were obtained from a ‘Medication and Pregnancy’ registry, built by linking 3 databases (RAMQ, Med-Écho, ISQ) and a self-administered questionnaire. The initial cohort included 109,344 women who had been pregnant between 01/01/1998 and 12/31/2002. Eligible women had (1) to be 15–45 years of age on the 1st day of gestation, (2) be insured by the RAMQ drug plan for ≥ 12 months prior to the 1st day of gestation and during pregnancy, (3) have ≥ 1 diagnosis of psychiatric disorder before pregnancy, (4) have used antidepressants for ≥ 30 days in the year prior to pregnancy, and (5) have a pregnancy ending with a