Neurochemical effects of prenatal haloperidol exposure

Safety of psychotropic medications in pregnancy: an umbrella review

Weighing risks and benefits of the use of psychotropic medications during pregnancy remains a challenge worldwide. We systematically assessed the strength of associations between psychotropic medication use in pregnant people with mental disorders and various adverse health outcomes in both pregnant people and foetuses. Systematic reviews with meta-analyses of observational studies investigating the association between exposure to psychotropic medication in pregnancy and any adverse health outcomes were included. Credibility was graded into convincing, highly suggestive, suggestive, weak or not significant. Quality of the meta-analyses and of individual studies were assessed with A Measurement Tool to Assess Systematic Reviews 2 (AMSTAR 2) the Newcastle-Ottawa Scale (NOS), respectively. We considered 21 meta-analyses encompassing 17,290,755 participants (AMSTAR 2 high = 1, low = 12, or critically low = 8). Evidence was suggestive for: (1) preterm birth in pregnant people with either any mental disorder (equivalent odds ratio 1.62 (95% confidence interval 1.24-2.12) or depression (1.65 [1.34-2.02]) receiving antidepressants during any trimester of pregnancy; (2) small for gestational age for pregnant people with depression receiving a SSRI during any trimester of pregnancy (1.50 [1.19-1.90]); and (3) major congenital malformation (1.24 [1.09-1.40]) or cardiac malformations (1.28 [1.11-1.47]) in babies for pregnant people with depression or anxiety receiving paroxetine during first trimester of pregnancy. Additional associations were supported by weak evidence, or were not statistically significant. This umbrella review found no convincing or highly suggestive level of evidence of adverse health outcomes associated with psychotropic medication use in pregnant people with mental disorders.

Prenatal exposition to haloperidol: A preclinical narrative review

Pre-existing maternal mental disorders may affect the early interactions between mother and baby, impacting the child's psychoemotional development. The typical antipsychotic haloperidol can be used during pregnancy, even with some restrictions. Its prescription is not limited to psychotic disorders, but also to other psychiatric conditions of high incidence and prevalence in the woman's fertile period. The present review focused on the preclinical available data regarding the biological and behavioral implications of embryonic exposure to haloperidol. The understanding of the effects of psychotropic drugs during neurodevelopment is important for its clinical aspect since there is limited evidence regarding the risks of antipsychotic drug treatment in pregnant women and their children. Moreover, a better comprehension of the mechanistic events that can be affected by antipsychotic treatment during the critical period of neurodevelopment may offer insights into the pathophysiology of neurodevelopmental disorders. The findings presented in this review converge to the existence of several risks associated with prenatal exposure to such medication and emphasize the need for further studies regarding its dimensions.

Metabolomics profiling of haloperidol and validation of thromboxane-related signaling in the early development of zebrafish

Haloperidol is a common butyrophenone-derivative antipsychotic drug that is used clinically to treat schizophrenia and to control Tourette disorder. Haloperidol has been shown to be an embryonic toxicant and to cause a variety of adverse effects that affect human embryonic development. However, the pathway impaired by haloperidol during the developmental stages remains unclear. To elucidate the innate toxicological pathway of haloperidol, we investigated the lethality of haloperidol during the embryonic development of zebrafish. We observed that haloperidol caused serious morphological changes, with an LD₅₀ of 9.7 x 10^-6 ± 2.4 x 10^-6 μg/L. Next, we established a systematic approach to perform metabolite profiling in embryonic zebrafish with various concentrations of haloperidol and analyzed the metabolites using ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC/Q-TOF MS). A total of 304 metabolites were identified and 86 metabolites were chosen to predict potential pathways. Among the metabolites, we found through prediction that numerous metabolomics-biological pathways are associated with haloperidol, including peroxisome-proliferator-activated receptor (ppar), thromboxane, and mTOR signaling. Quantitative real time-qPCR was then used to validate the gene expression potentially associated with the thromboxane, which is a metabolic product of arachidonic acid and considered to be important for cell proliferation and the inflammatory response. To sum up, analysis of metabolites in the zebrafish model provides a system for mining biomarkers that reflect biological significance and highlight the therapeutic potency in humans. In addition, it may show potential for application to other pharmaceuticals to identify their various activities and clarify functional mechanisms in the future.

Expanding the test set: Chemicals with potential to disrupt mammalian brain development

High-throughput test methods including molecular, cellular, and alternative species-based assays that examine critical events of normal brain development are being developed for detection of developmental neurotoxicants. As new assays are developed, a "training set" of chemicals is used to evaluate the relevance of individual assays for specific endpoints. Different training sets are necessary for each assay that would comprise a developmental neurotoxicity test battery. In contrast, evaluation of the predictive ability of a comprehensive test battery requires a set of chemicals that have been shown to alter brain development after in vivo exposure ("test set"). Because only a small number of substances have been well documented to alter human neurodevelopment, we have proposed an expanded test set that includes chemicals demonstrated to adversely affect neurodevelopment in animals. To compile a list of potential developmental neurotoxicants, a literature review of compounds that have been examined for effects on the developing nervous system was conducted. The search was limited to mammalian studies published in the peer-reviewed literature and regulatory studies submitted to the U.S. EPA. The definition of developmental neurotoxicity encompassed changes in behavior, brain morphology, and neurochemistry after gestational or lactational exposure. Reports that indicated developmental neurotoxicity was observed only at doses that resulted in significant maternal toxicity or were lethal to the fetus or offspring were not considered. As a basic indication of reproducibility, we only included a chemical if data on its developmental neurotoxicity were available from more than one laboratory (defined as studies originating from laboratories with a different senior investigator). Evidence from human studies was included when available. Approximately 100 developmental neurotoxicity test set chemicals were identified, with 22% having evidence in humans.

Changes induces by haloperidol (antidepressant drug) on the developing retina of the chick embryo

Morphological and histological studies were done on the retina of chick embryos of 6th, 10th and 16th days of incubation by a single dose of haloperidol (0.25 mg/egg), injected on day zero and 5 of incubation. To get an idea about the extent of the teratogenic effect of this drug on the development retina. Sign of malformation in the chick embryo after administration of haloperidol were seen as absent of the ear vesicles, eyes or decreased size of them. Retardation of growth of the retina at 6th, 10th and 16th days treated chick embryo were observed as evidenced of reduction of the size of the retina, associated with sign of degeneration of the retina cells.

CONCLUSION

The injection of haloperidol drug give rise to several side effects as retardation of growth and degeneration of the cells. The decrease of the thickness of the layers and less density of the cells was related to direct effect of the drug on the cells of this organ. Also on the DNA formation and on the retardation of cellular mitotic activates, therefore the retina appeared decrease in thickness and less cell density with degeneration its cells.

Prenatal antipsychotic exposure and neuromotor performance during infancy

CONTEXT

Despite the expanding clinical utility of antipsychotics beyond psychotic disorders to include depressive, bipolar, and anxiety disorders, reproductive safety data regarding the neurodevelopmental sequelae of fetal antipsychotic exposure are scarce.

OBJECTIVE

To examine whether intrauterine antipsychotic exposure is associated with deficits in neuromotor performance and habituation in 6-month-old infants.

DESIGN, SETTING, AND PARTICIPANTS

A prospective controlled study was conducted from December 1999 through June 2008 at the Infant Development Laboratory of the Emory Psychological Center examining maternal-infant dyads (N=309) at 6 months postpartum with pregnancy exposure to antipsychotics (n=22), antidepressants (n=202), or no psychotropic agents (n=85). Examiners masked to maternal-infant exposure status administered a standardized neuromotor examination (Infant Neurological International Battery [INFANIB]) that tests posture, tone, reflexes, and motor skills and a visual habituation paradigm using a neutral female face.

MAIN OUTCOME MEASURES

The INFANIB composite score; number of trials required to achieve a 50% decrease in infant fixation during a visual habituation task; and mean time looking at the stimulus across 10 trials.

RESULTS

Infants prenatally exposed to antipsychotics (mean=64.71) showed significantly lower INFANIB scores than those with antidepressant (mean=68.57) or no psychotropic (mean=71.19) exposure, after controlling for significant covariates (F(2,281)=4.51; P=.01; partial η(2)=0.033). The INFANIB scores were also significantly associated with maternal psychiatric history, including depression, psychosis, and overall severity/chronicity (P's.05) and maternal depression during pregnancy was associated with less efficient habituation (r(245)=0.16; P.02). There were no significant differences regarding habituation between medication exposure groups.

CONCLUSIONS

Among 6-month-old infants, a history of intrauterine antipsychotic exposure, compared with antidepressant or no psychotropic exposure, was associated with significantly lower scores on a standard test of neuromotor performance, highlighting the need for further scrutiny of the reproductive safety and neurodevelopmental sequelae of fetal antipsychotic exposure. Disentangling medication effects from maternal illness effects, which also contributed, remains a critical challenge.

Activity-dependent reduction of dopamine D2 receptors during a postnatal critical period of plasticity in rat striatum is not affected by prenatal haloperidol treatment

Motor activity induced in the Circling Training test (CT) during a postnatal (PN) critical period of plasticity (PN30-37) produces a long-lasting decrease in the number of binding sites and mRNA expression levels of the dopamine D2 receptor (D2R) in rat striatum. Prenatal exposure to the antipsychotic haloperidol also decreases postnatal levels of the striatal D2R in the offspring. We examined whether such fetal exposure to haloperidol could affect the activity-dependent reduction of the D2R system during the critical period. Half of the male offspring exposed to either haloperidol (2.5 mg/kg/day), i.p.) or saline during gestational days 5-18 were subjected to the CT during the critical period, while the remaining represented CT control animals. The adult number of binding sites and mRNA expression levels of the striatal D2R at PN90 were not changed by prenatal haloperidol treatment alone. On the other hand, only pups subjected to the CT during the critical period showed decreases in both studied parameters, regardless the prenatal treatment. These findings indicated that the postnatal reduction of the striatal D2R binding induced prenatally by haloperidol does not affect long-lasting activity-dependent plastic changes on the same receptor system elicited by motor activity in an ontogenetic critical period of plasticity in rat striatum.

Differently lasting effects of prenatal and postnatal chronic clozapine/haloperidol on activity and memory in mouse offspring

We evaluated the behavioral effects of chronic haloperidol (HAL) and clozapine (CLO) during gestation and CNS development, compared with transient treatments that stopped 1-3 weeks before the test.

RESULTS

1) Chronic HAL (6 mg/l in drinking water) but not HAL-withdrawal caused hypo-activity in open-field test on postnatal days (PNDs) 35, 42 and 56. However, hyper-activity was found in both CLO (90 mg/l) and CLO-withdrawal pups. 2) In the step-through test, retention performance was significantly higher in HAL-treated mice than in the controls on PND 42, as well as in withdrawal mice on PNDs 35 and 42. However, both chronic CLO (90 mg/l) exposure and CLO-withdrawal tended to improve the acquisition of memory. Furthermore, chronic CLO (180 mg/l) ameliorated scopolamine (3 mg/kg)-induced impairment of memory on PND 56. 3) In the water-maze test, both chronic HAL and HAL-withdrawal treatments significantly impaired performance on the 4th training day at PND 35, but not PNDs 42 and 56. Neither chronic CLO exposure nor CLO-withdrawal affected spatial memory. 4) Body weight following HAL/CLO administration decreased when compared with the controls during PND 21-35, but approached control levels at PND 40.

CONCLUSION

HAL doesn't elicit permanent behavioral changes in offspring. By contrast, CLO had longer-lasting effects than HAL. The pups at age before PND 35 seem more sensitive to HAL/CLO than elder pups.

Structural Effects and Neurofunctional Sequelae of Developmental Exposure to Psychotherapeutic Drugs: Experimental and Clinical Aspects

The advent of psychotherapeutic drugs has enabled management of mental illness and other neurological problems such as epilepsy in the general population, without requiring hospitalization. The success of these drugs in controlling symptoms has led to their widespread use in the vulnerable population of pregnant women as well, where the potential embryotoxicity of the drugs has to be weighed against the potential problems of the maternal neurological state. This review focuses on the developmental toxicity and neurotoxicity of five broad categories of widely available psychotherapeutic drugs: the neuroleptics, the antiepileptics, the antidepressants, the anxiolytics and mood stabilizers, and a newly emerging class of nonprescription drugs, the herbal remedies. A brief review of nervous system development during gestation and following parturition in mammals is provided, with a description of the development of neurochemical pathways that may be involved in the action of the psychotherapeutic agents. A thorough discussion of animal research and human clinical studies is used to determine the risk associated with the use of each drug category. The potential risks to the fetus, as demonstrated in well described neurotoxicity studies in animals, are contrasted with the often negative findings in the still limited human studies. The potential risk fo the human fetus in the continued use of these chemicals without more adequate research is also addressed. The direction of future research using psychotherapeutic drugs should more closely parallel the methodology developed in the animal laboratories, especially since these models have already been used extremely successfully in specific instances in the investigation of neurotoxic agents.

Effect of prenatal haloperidol exposure on behavioral alterations in rats

Pregnant Charles-Foster rats were exposed to haloperidol (HAL), a neuroleptic drug that binds to and blocks dopamine (DA) receptor subtypes at a dose of 2.5 mg/kg body weight (intraperitoneally) from Gestation Day (GD) 12 to 20. The animals from both treated as well as vehicle control groups were allowed to deliver on GD 21. The offspring culled at birth on the basis of sex and weight were subjected to behavioral tests at the age of 8 weeks. The HAL-treated rat offspring showed a significant increase in anxiogenic behavior on the open field, elevated plus-maze and elevated zero-maze tests when compared with the vehicle-treated (control) rat offspring of the same age group. These findings suggest that prenatal exposure to HAL during a critical period of brain development leaves a lasting imprint on the brain, resulting in abnormal anxiety states, possibly through dopaminergic neurotransmission mechanisms.

Effect of prenatal administration of haloperidol, risperidone, quetiapine and olanzapine on spatial learning and retention in adult rats

The typical antipsychotic haloperidol and atypical antipsychotics olanzapine, quetiapine and risperidone were administered to pregnant Sprague-Dawley dams in the drinking water from Days 8 to 18 of gestation. When the offspring reached adulthood (2 months), spatial learning and short-term retention were examined using the radial arm maze. Results showed that prenatal administration of haloperidol, risperidone and quetiapine impaired learning but only haloperidol and risperidone disrupted short-term retention.

Prenatal haloperidol reduces the number of active midbrain dopamine neurons in rat offspring

The dopamine (DA) receptor antagonist, haloperidol (HAL, 1.25 or 5 mg/kg), or vehicle, dimethyl sulfoxide (DMSO), was administered (SC) daily to pregnant Sprague-Dawley dams from gestational day (GD) 8 to GD 20. The average body weight of 2-week-old male offspring was significantly lower in all of the HAL-treated groups relative to controls. In extracellular electrophysiological studies, the male 2-week-old offspring from all HAL treatment groups were found to have significantly reduced average numbers of spontaneously active midbrain dopamine (DA)-containing neurons in both the substantia nigra (A9) and the ventral tegmental area (A10) relative to controls. In DA neurons classified as bursting neurons, HAL exposure (5 mg/kg) caused a significantly increased level of burst activity in A10 but not A9 DA neurons relative to controls. For both the A9 and A10 regions, the proportion of DA neurons classified as bursting or nonbursting was unaffected by HAL treatment. These results suggest that prenatal HAL exposure influences the development of midbrain DA neurons.

Functional and molecular differentiation of the dopamine system induced by neonatal denervation

The administration of the neurotoxin 6-hydroxydopamine (6-OHDA) to damage the mesostriatal dopamine (DA) system in the neonate results in different neurochemical and behavioral consequences as compared to lesions made in adulthood. There have been few direct data to support the conclusion that the behavioral changes following neonatal 6-OHDA lesions reflect plasticity of the DA system. It is our hypothesis that the plasticity of the developing DA system is fundamentally different from that of the adult. Responses to 6-OHDA lesions can only be understood within the context of the status of the mesostriatal DA system at the time of the lesion. There are stages of development in the early postnatal period when certain components of the mesostriatal DA system are differentially sensitive to 6-OHDA lesions. These "windows" of vulnerability can be predicted from an analysis of the developmental expression of DA receptors and the maturation of the subpopulation of the mesostriatal DA system that innervates them. We review the differences in the behavioral plasticity of the adult and neonate sustaining 6-OHDA lesions to the mesostriatal DA system, the mechanisms responsible for the behavioral plasticity in the adult, and our conceptualization of which mechanisms are affected in the neonate.

Prenatal haloperidol induces a selective reduction in the expression of plasticity-related genes in neonate rat forebrain

Haloperidol, a dopamine receptor antagonist clinically used as an antipsychotic drug, induces long-term deleterious effects in offspring development when administered prenatally. However, the basis for this overall response to the drug remains unknown. Here we describe that prenatal administration of haloperidol in rats induces a drastic and selective reduction in the expression of plasticity-related genes in neonate forebrain, but not in mesencephalon. GABAergic and enkephalinergic markers such as glutamic acid decarboxylase activity and mRNA, and preproenkephalin mRNA were also diminished in forebrain. However, the expression of other genes such as epidermal growth factor-receptor, glial fibrillary acidic protein, and several proto-oncogenes (src, fos and myc), and a cholinergic marker such as choline acetyltransferase activity were unaltered. In addition, haloperidol promoted a significant decrease in mitotic cell number and cellular density in the striatum, one of the forebrain regions with the highest dopamine receptor density. These findings suggest that prenatal dopamine receptor occupancy may be a critical factor in controlling the development of forebrain target cells through mechanisms involving changes in the expression of plasticity-related genes.

Prenatal haloperidol exposure: effects on brain weights and caudate neurotransmitter levels in rats

Monoamines may exert a trophic effect on early brain development. To assess the role of dopamine in prenatal neurological development of the rat, haloperidol (HAL) was given in daily 2.5 or 5 mg/kg SC doses to dams over gestational days 6 to 20. This treatment regime did not enhance fetal mortality, but did produce reliable, if modest, stunting of the body and brain weight of offspring. The 5 mg/kg HAL dose consistently reduced offspring brain weight to roughly 90% of controls. This effect was probably permanent, in that it was seen throughout maturation and in adults as late as 140 days of postnatal age. Appropriate controls showed that this effect was not due to drug-induced reductions in food intake, to the presence of HAL in maternal milk, or to behavioral abnormalities in HAL-exposed dams. These effects had, at best, modest regional specificity, in that most brain regions were affected, independently of degree of dopaminergic innervation. Closer investigation of HAL effects on the striatum suggested that this permanent weight reduction was not accompanied by alterations in striatal concentrations of monoamines, monoamine metabolites, amino acids, choline, acetylcholine, DNA, protein, or water. It is concluded that prenatal HAL does stunt growth, but that this effect may not involve a direct drug influence restricted to the fetal dopamine system in the brain.

Effects of a single haloperidol application to neonatal and early postnatal rats on the neurotransmitter content in the corpus striatum

We investigated the influence of the dopamine antagonist haloperidol on the neurotransmitter content in the developing rat brain. Dopamine (DA), serotonin (5-HT) and the corresponding metabolites dopac, HVA and HIAA were determined in the corpus striatum of the rat between day 1 and day 21 pn by HPLC with electro-chemical detection. A consistent increase in the content of dopamine was found during postnatal development. The concentrations (ng/g wet tissue; mean +/- standard deviation) increased from 793 +/- 237 on day 1 pn to 4584 +/- 581 on day 21 pn, but remained still lower than in adult animals (9763 +/- 494). Similar results were found for the metabolites dopac and HVA. The content of dopac increased from 59 +/- 22 (day 1 pn) to 551 +/- 59 (day 21 pn) and the content of HVA from 53 +/- 18 (day 1 pn) to 419 +/- 41 (day 21 pn). Both metabolites were also about two times lower than in adult animals (dopac 1090 +/- 282, HVA 744 +/- 206). In contrast to dopamine and its metabolites we found no age-dependent changes in the content of 5-HT from day 1 pn (99 +/- 11) to day 14 pn (121 +/- 21). A remarkable increase in the content of 5-HT was seen from day 14 pn to day 21 pn (438 +/- 56), reaching almost adult levels (570 +/- 92). The metabolite HIAA was nearly three times higher on day 21 pn (610 +/- 123) than on day 14 pn (223 +/- 28) and two times higher than in adults (321 +/- 58).(ABSTRACT TRUNCATED AT 250 WORDS)

Differential ontogeny of functional dopamine and muscarinic receptors mediating presynaptic inhibition of neurotransmitter release and postsynaptic regulation of adenylate cyclase activity in rat striatum

To study the ontogeny of functional striatal dopamine (DA) D2 and muscarinic receptors we determined the first appearance of the inhibitory effects of activation of autoreceptors on neurotransmitter release and that of postsynaptic receptors on adenylate cyclase activity in striatal slices of rat foetuses and pups. On embryonic day 17 (E17), activation of D2 receptors with LY 171555 (1 microM) resulted in a 50% inhibition of the electrically evoked release of [3H]DA from superfused striata, indicating that D2 autoreceptors are functional at that time. Stimulation of adenylate cyclase activity with the Da D1 agonist SK&F 38393 could also be determined in the striatum on E17. In contrast, inhibition of D1-stimulated adenylate cyclase activity through activation of postsynaptic D2 receptors did not occur until postnatal day 14 (P14), whereas activation of postsynaptic muscarinic receptors with oxotremorine (1 microM) resulted in 30% inhibition already on E17. Endogenous activation of muscarinic receptors with physostigmine (1 microM) was ineffective in the prenatal period, but its inhibitory effect on D1-stimulated adenylate cyclase increased strongly between P7 and P21. Inhibition of striatal [3H]acetylcholine (ACh) release by activation of muscarinic receptors could not be determined until P7, because the release of the neurotransmitter was not measurable before that day. But on P7, oxotremorine and physostigmine (as well as the D2 receptor agonist LY 171555) reduced the electrically evoked release of [3H]ACh from striatal slices. Taken together, these data show that there is a marked time difference between the coupling of D2 receptors and that of the D1 and muscarinic receptors to adenylate cyclase in the developing striatum.(ABSTRACT TRUNCATED AT 250 WORDS)

Developmental toxicity of the dopamine agonist pergolide mesylate in CD-1 mice. I: Gestational exposure

Pergolide was given by oral gavage to mated CD-1 female mice at doses of 0, 1, 20, or 60 mg/kg/day on gestation days (GD) 6-15. Animals assigned to the teratology segment were killed on GD 18 for evaluation of maternal organ weights, and fetal viability, weights and morphology. Animals assigned to the postnatal segment were allowed to deliver and physical development and behavioral performance of the progeny were monitored until weaning. Maternal organ weights were collected at termination after weaning. One F1 offspring per sex per litter was maintained for postweaning physical, behavioral and reproductive assessments and for terminal examinations and organ weight evaluations. No adverse effects of pergolide treatment were found in the 1 mg/kg/day group. Dose-related hyperactivity, chewing and squinting that were consistent with dopaminergic stimulation occurred following dosing in the 20 and 60 mg/kg/day groups; F0 body weights and food consumption were reduced during the initial phase of treatment in the 60 mg/kg/day group. Gravid uterine weights and fetal weights were decreased in the 60 mg/kg/day group of the teratology segment, but there was no indication of teratogenicity in any group. Mammary inflammation, attributed to increased progeny suckling, occurred during the second week postpartum in a few postnatal segment females of the 20 and 60 mg/kg/day groups. Mean negative geotaxis performance was delayed slightly, but mean progeny survival and body weights were not affected. Although after weaning the F1 offspring from the treatment-derived groups tended to weigh more than controls and to perform more effectively in the active avoidance task, these findings were attributed to unusually low values obtained in the control group. Startle amplitudes were increased significantly in the males from the 60 mg/kg/day treatment-derived group. These dose-related maternal and developmental findings were all consistent with the mixed D1/D2 agonist properties of pergolide mesylate, and suggest that only very high doses may result in persistent effects on the developing central dopaminergic systems.

Developmental toxicity of the dopamine agonist pergolide mesylate in CD-1 mice. II: Perinatal and postnatal exposure

Pergolide mesylate is a dopamine agonist and, therefore, reduces prolactin secretion. In Experiment I, pregnant mice were given oral doses of 0, 0.1, 0.3, 1.0 or 3.0 mg/kg/day pergolide on GD 15 through PD 10 or 20 to identify a tolerated dose which would not markedly reduce offspring survival during late gestational and lactational exposure. Offspring survival was not affected at any dose, but dose-related decreases in progeny body weights occurred at weaning. On PD 10, suckling-induced increases in maternal serum prolactin concentrations did not occur in dams treated with 3.0 mg/kg/day. In Experiment II, pregnant mice were given oral doses of 0, 0.002, 0.1 or 3.0 mg/kg/day pergolide on GD 15 through PD 20. Dams were allowed to deliver and maintain their offspring throughout a 21-day lactation period. Growth and behavioral performance of one F1 male and one F1 female per litter were monitored, followed by a reproduction trial and terminal organ weight measurements. There were no treatment-related effects on maternal body weights, food consumption, or terminal organ weights and pathology. Three dams showed overt signs of mammary inflammation and lactational insufficiency and mean progeny survival was decreased slightly in the 3.0 mg/kg/day group. There were no adverse effects on growth, development or reproductive performance in the F1 treatment-derived generation. Neonatal negative geotaxis, 1-h activity levels at 30 and 60 days of age, auditory startle habituation at 55 days of age, and two-way active avoidance performance at 65 days of age were not affected significantly by treatment. Thus doses of pergolide that did not inhibit lactation completely in the F0 dams were found to have no enduring effects on offspring development.

Investigation of striatal dopamine D2 receptor acquisition following prenatal neuroleptic exposure

To test the hypothesis that neuroleptic blockade impairs the development of striatal dopamine D2 receptors, pregnant rats were given haloperidol, thiothixene, or trifluoperazine for gestational days 15-18 (short-term exposure) or days 5-20 (long-term exposure). All of the drugs were demonstrated to cross the placenta and enter the fetal brains equally well. Striatal dopamine D2 receptors of the pups were assayed on postnatal day 14. Neither receptor density nor receptor affinity was altered significantly by the short- or long-term prenatal neuroleptic treatment.

Behavioral effects of prenatal haloperidol exposure

Pregnant albino rats were exposed to vehicle (CON), 2.5 mg/kg (LOW) or 5.0 mg/kg (HIGH) haloperidol (HAL) from the sixth through the twentieth day of gestation. The effect of prenatal HAL exposure on offspring was assessed with the following five behavioral measures: 1) milk-induced behavioral activation on the sixth postnatal day (PND 6), 2) shock-precipitated wall climbing (PNDs 9, 11, 13, 15 and 17), 3) amphetamine-induced stereotypies (PND 30), 4) apomorphine-induced stereotypies (PND 30) and 5) duration of barbiturate anesthesia (PNDs 34 and 62). Measures taken very early in life indicated that prenatal HAL reduced arousal. Inactivity scores were elevated in HAL-exposed pups on PND 6 during milk-induced behavioral activation. Shock-precipitated wall climbing was reduced in the HAL animals on PNDs 9 and 11, but not thereafter. At PND 30, no prenatal treatment effect was detectable on stimulant-induced stereotypies or on duration of barbiturate anesthesia. On PND 62, barbiturate anesthesia duration was significantly reduced in both sexes of HIGH HAL animals. These findings suggest that prenatal HAL effects follow a dynamic, changing course as the exposed rat pup matures. Early reductions in arousal (milk-induced behavior and shock-precipitated wall climbing) wane with age, perhaps to be replaced by an actual increase in arousal as HAL pups approach adulthood.