Maternal cocaine administration in mice alters DNA methylation and gene expression in hippocampal neurons of neonatal and prepubertal offspring.

Previous studies documented significant behavioral changes in the offspring of cocaine-exposed mothers. We now explore the hypothesis that maternal cocaine exposure could alter the fetal epigenetic machinery sufficiently to cause lasting neurochemical and functional changes in the offspring. Pregnant CD1 mice were administered either saline or 20 mg/kg cocaine twice daily on gestational days 8-19. Male pups from each of ten litters of the cocaine and control groups were analyzed at 3 (P3) or 30 (P30) days postnatum. Global DNA methylation, methylated DNA immunoprecipitation followed by CGI(2) microarray profiling and bisulfite sequencing, as well as quantitative real-time RT-PCR gene expression analysis, were evaluated in hippocampal pyramidal neurons excised by laser capture microdissection. Following maternal cocaine exposure, global DNA methylation was significantly decreased at P3 and increased at P30. Among the 492 CGIs whose methylation was significantly altered by cocaine at P3, 34% were hypermethylated while 66% were hypomethylated. Several of these CGIs contained promoter regions for genes implicated in crucial cellular functions. Endogenous expression of selected genes linked to the abnormally methylated CGIs was correspondingly decreased or increased by as much as 4-19-fold. By P30, some of the cocaine-associated effects at P3 endured, reversed to opposite directions, or disappeared. Further, additional sets of abnormally methylated targets emerged at P30 that were not observed at P3. Taken together, these observations indicate that maternal cocaine exposure during the second and third trimesters of gestation could produce potentially profound structural and functional modifications in the epigenomic programs of neonatal and prepubertal mice.

Identification of protein biomarkers for schizophrenia and bipolar disorder in the postmortem prefrontal cortex using SELDI-TOF-MS ProteinChip profiling combined with MALDI-TOF-PSD-MS analysis.

This paper describes the high-throughput proteomic analysis of the dorsolateral prefrontal cortex (DLPFC) from schizophrenia (SCHIZ), bipolar (BD), and normal control cohorts from the Harvard Brain Tissue Resource Center performed using ProteinChip technology based on the surface-enhanced laser desorption/ionization time of flight mass spectrometry (SELDI-TOF-MS). The resultant profiles were utilized in classification-tree algorithms for selection of protein biomarker peaks contributing maximally to the differentiation between the examined diagnostic cohorts. Twenty-four such protein biomarker peaks were identified. All of them had lower levels in the SCHIZ cohort as compared to the BD cohort. Also, 21 of these peaks were down-regulated in the SCHIZ cohort vs. the control cohort, and 7 peaks were up-regulated in the BD cohort vs. the control cohort. The proteins constituting these biomarker peaks were recognized via matrix-assisted laser desorption time of flight/postsource decay mass spectrometry (MALDI-TOF-PSD-MS). These proteins represent a wide range of functional groups involved in cell metabolism, signaling cascades, regulation of gene transcription, protein and RNA chaperoning, and other aspects of cellular homeostasis. Finally, after statistical evaluation suggesting that the selected protein biomarkers are not significantly impacted by epidemiological/tissue storage parameters (although, influence of antipsychotic and mood stabilizing drugs could not be fully excluded), the ProteinChip-based profiling was engaged again to demonstrate that the detected SCHIZ-associated changes in the levels of our protein biomarkers could also be seen in DLPFC samples from the brain collection of the Mount Sinai Medical School/Bronx Veteran Affairs Medical Center. This study demonstrates the usefulness of ProteinChip-based SELDI-TOF protein profiling in gaining insight into the molecular pathology of SCHIZ and BD as it points to changes in protein levels characterizing these diseases.

Consequences of paternal cocaine exposure in mice.

The present study examined the potential neuroteratological effects of paternal cocaine (COC) exposure using the novel mouse model of inhalational drug administration. In this model, mice were trained to self-administer COC in multi-hour daily inhalation sessions reminiscent of crack binges. The controls included males pair-fed with COC-inhaling animals as well as ad-lib-fed males. All males were bred with drug-naive females. The newborn pups sired by COC-inhaling males had a reduced biparietal head diameter, suggesting a decreased cerebral volume. When the pups reached adulthood, their sustained visuo-spatial attention and spatial working memory were tested using a 5-arm maze paradigm. During the attention tests, the percentage of correct trials at the shortest stimulus duration employed in the study (0.5 s) was significantly lower for the male offspring of COC-inhaling fathers as compared to the offspring of both pair-fed and ad-lib-fed controls. For the females sired by COC-inhaling fathers, the deficit was observed at light stimulus durations of 0.5 and 0.75 s. Also, during the working memory tests, the male offspring of COC-inhaling fathers required more sessions than the offspring of either pair-fed or ad-lib-fed fathers to reach the selected criterion at retention intervals of 16 min and longer. The impairment of working memory in female offspring of COC-inhaling fathers was even stronger, as the offspring needed more sessions to reach the criterion as compared to their control counterparts, even at retention intervals as short as 4 min. These findings suggest that paternal COC abuse prior to coitus may impact the development of the offspring, particularly if they are females. We further showed that chronic COC exposure in male mice does not result in substantial breakage of spermatozoal DNA, but significantly alters expression of DNA methyltransferases 1 and 3a in the germ cell-rich seminiferous tubules of the testis. Since these enzymes are essential for generating and maintaining parental gene imprinting in germ cells, our observations point to an intriguing possibility that COC may cause paternally induced neuroteratological effects by interfering with gene-imprinting patterns in male gametes.

Inhalational model of cocaine exposure in mice: neuroteratological effects.

We developed a novel inhalation-based mouse model of prenatal cocaine exposure. This model approximates cocaine abuse via smoking, the preferred route of cocaine administration by heavy drug users. The model is also characterized by (i) absence of procedural stress from drug administration, (ii) long-term drug exposure starting weeks before pregnancy and continuing throughout the entire gestation, and (iii) self-administration of cocaine in multi-hour daily sessions reminiscent of drug binges, which allows animals to set up the levels of their own drug consumption. The offspring of female mice inhaling cocaine in our model displayed no gross alterations in their cortical cytoarchitecture. These offspring, however, showed significant impairments in sustained attention and spatial working memory. We hope that the introduction of the present model will lead to a significant increase in our understanding of outcomes of prenatal cocaine exposure.

Neonatal local noxious insult affects gene expression in the spinal dorsal horn of adult rats.

Neonatal noxious insult produces a long-term effect on pain processing in adults. Rats subjected to carrageenan (CAR) injection in one hindpaw within the sensitive period develop bilateral hypoalgesia as adults. In the same rats, inflammation of the hindpaw, which was the site of the neonatal injury, induces a localized enhanced hyperalgesia limited to this paw. To gain an insight into the long-term molecular changes involved in the above-described long-term nociceptive effects of neonatal noxious insult at the spinal level, we performed DNA microarray analysis (using microarrays containing oligo-probes for 205 genes encoding receptors and transporters for glutamate, GABA, and amine neurotransmitters, precursors and receptors for neuropeptides, and neurotrophins, cytokines and their receptors) to compare gene expression profiles in the lumbar spinal dorsal horn (LDH) of adult (P60) male rats that received neonatal CAR treatment within (at postnatal day 3; P3) and outside (at postnatal 12; P12) of the sensitive period. The data were obtained both without inflammation (at baseline) and during complete Freund's adjuvant induced inflammation of the neonatally injured paw. The observed changes were verified by real-time RT-PCR. This study revealed significant basal and inflammation-associated aberrations in the expression of multiple genes in the LDH of adult animals receiving CAR injection at P3 as compared to their expression levels in the LDH of animals receiving either no injections or CAR injection at P12. In particular, at baseline, twelve genes (representing GABA, serotonin, adenosine, neuropeptide Y, cholecystokinin, opioid, tachykinin and interleukin systems) were up-regulated in the bilateral LDH of the former animals. The baseline condition in these animals was also characterized by up-regulation of seven genes (encoding members of GABA, cholecystokinin, histamine, serotonin, and neurotensin systems) in the LDH ipsilateral to the neonatally-injured paw. The largest aberration in gene expression, however, was observed during inflammation of the neonatally injured hindpaws in the ipsilateral LDH, which included thirty-six genes (encoding numerous members of glutamate, serotonin, GABA, calcitonin gene-related peptide, neurotrophin, and interleukin systems). These findings suggest that changes in gene expression may be involved in the long-term nociceptive effects of neonatal noxious insult at the spinal level.

Cocaine-induced changes in the expression of apoptosis-related genes in the fetal mouse cerebral wall.

It has been demonstrated that exposure to cocaine increases cell death in the fetal CNS. To examine the molecular mechanisms of this effect, we employed mouse oligo microarrays followed by real-time reverse transcriptase-polymerase chain reaction (real-time RT-PCR) to compare expressions of apoptosis-related genes in the cerebral wall of 18-day-old (E18) fetuses from cocaine-treated (20 mg/kg cocaine, s.c., b.i.d., E8th-E18th) and drug-naive (saline, s.c.) mice. Out of approximately 400 relevant genes in the arrays, 53 showed alterations in expression in cocaine-exposed fetuses. Upregulation was observed in 35 proapoptotic and 8 antiapoptotic genes; 4 proapoptotic and 6 antiapoptotic genes were down-regulated. The affected genes encode a wide range of apoptosis-related proteins, including death receptors (NTF-R1, NTF-R2, DR3, DR5, LTbeta-R, GITR, P57 TR-1) and their adaptor and regulatory proteins (MASGE-D1, TRAF-2, SIVA, MET, FLIP, FAIM, IAP1, ATFA), members of transcription regulatory pathways (JNK, NF-kappaB, P53), members of BCL-2 family of proteins (BID, BAD, BAX, BIK, NIP21, NIP3, NIX, BCL-2), DNA damage sensor (PARP-1), caspases and their substrates and regulatory proteins (caspases 8, 4, 9, and 3, ACINUS, CIDE-A, CIDE-B, GAS2), mitochondrially released factors (cytochrome c, AIF, PRG3), specific endoplasmic reticulum- and oxidative stress-associated factors (BACH2, ABL1, ALG2, CHOP), members of cell survival AKT and HSP70 pathways (PIK3GA, PTEN, HSP70, BAG1, BAG2), and others. This suggests that cocaine affects survival of developing cerebral cells via multiple apoptosis-regulating mechanisms.

Neuropathology of the cerebral cortex observed in a range of animal models of prenatal cocaine exposure may reflect alterations in genes involved in the Wnt and cadherin systems.

Several recent reports show that the cerebral cortex in humans and animals with altered expressions of Wnt/cadherin network-associate molecules display cytoarchitectural abnormalities reminiscent of cortical dysplasias seen in some (mouse-, rat-, and monkey-based) animal models of prenatal cocaine exposure. Therefore, we employed oligo microarrays followed by real-time RT-PCR to compare expressions of genes involved in Wnt and cadherin systems in the cerebral wall of 18-day-old (E18) fetuses from cocaine-treated (20 mg/kg cocaine, s.c., b.i.d., E8-18) and drug-naive (saline, s.c.) mice. The pregnant mice chronically treated with cocaine in the above-described manner represent one of the animal models producing offspring with widespread cortical dysplasias. Out of more than 150 relevant genes in the arrays, 32 were upregulated and 9 were downregulated in cocaine-exposed fetuses. The majority of these genes (30 out of 41) were similarly affected in the frontal and occipital regions of the cerebral wall. We also used Western immunoblotting to examine the ability of cocaine to regulate the protein levels of beta-catenin, the key functional component of both Wnt and cadherin systems. While the total cell levels of beta-catenin were increased throughout the cerebral wall of cocaine-exposed fetuses, its nuclear (gene-transcription driving) levels remained unaltered. This suggests a transcription-unrelated role for cocaine-induced upregulation of this protein. Overall, our findings point to an intriguing possibility that that cerebral cortical dysplasias observed in several animal models of prenatal cocaine exposure may be at least in part related to alterations in the Wnt/cadherin molecular network.

D1 dopamine receptor regulation of the levels of the cell-cycle-controlling proteins, cyclin D, P27 and Raf-1, in cerebral cortical precursor cells is mediated through cAMP-independent pathways.

Previously, we demonstrated that dopamine D1 receptor (D1R) agonists inhibit epidermal growth factor (EGF)-induced passage of mouse fetal cerebral cortical precursor cells from the G1 phase to the S phase of the cell cycle. Here, we report that this action of D1R agonists may involve regulation of cyclin D, and P27, which respectively promote and suppress the G1 to S transition. Furthermore, regulation of Raf-1, a component of the receptor tyrosine kinase mitogen-activated protein kinase pathway engaged in the mitogenic activity of EGF, may also be involved. Specifically, levels of cyclin D and Raf-1 decrease, whereas those of P27 first increase and then decrease in a dose-dependent fashion in response to the D1R agonist, SKF38393. This agonist also promotes Raf-1 phosphorylation on serine 338 residue, suggesting increased activation of this protein. Only the latter effect can be blocked by adenylyl cyclase (AC) and cAMP-dependent protein kinase A (PKA) inhibitors, and mimicked by agonists of the cAMP signaling pathway. Another D1R agonist, SKF83959, which stimulates phospholipase Cbeta (PLCbeta) but not AC, reduces levels of Raf-1 and cyclin D similar to SKF38393. However, we detected only down-regulation of P27 by this agonist. Additionally, the concentration-dependent patterns of both SKF38393- and SKF83959-induced alterations in the levels of P27 closely resemble the effects of these ligands on the levels of the D1R-PLCbeta-associated second-messenger cascades linker, calcyon. These findings suggest that D1R-induced suppression of the cell cycle progression in EGF-supported fetal cortical precursor cells represents a net effect of competing cell cycle promoting and inhibiting molecular changes, which involve cyclin D, P27 and Raf-1. The data also show that cAMP second messenger cascade is not engaged in the D1R-induced regulation of the levels of these three proteins. Such regulation probably involves PLCbeta-associated pathways.

Neonatal hind paw injury alters processing of visceral and somatic nociceptive stimuli in the adult rat.

UNLABELLED: Tissue damage during the first few weeks after birth can have profound effects on sensory processing in the adult. We have recently reported that a short-lasting inflammation of the neonatal rat hind paw produces baseline hypoalgesia and exacerbated hyperalgesia after reinflammation of that hind paw in the adult. Because the contralateral hind paw and forepaws also displayed hypoalgesia, we speculated that effects of the initial injury were not somatotopically restricted and would alter visceral sensory processing as well. In the present study we tested this hypothesis by examining the effects of neonatal hind paw injury at P3 or P14 on visceral and somatic sensitivity in the adult rat. In P3 rats, the visceromotor response evoked by colorectal distention in the absence of colonic inflammation was attenuated in carrageenan-treated neonatal rats compared to naive rats. Colonic inflammation in the adult reversed this hypoalgesia and evoked a level of visceral hyperalgesia similar to naive rats. There were no consequences of the P14 injury observed in the adult. In a second experiment, colonic inflammation in naive rats induced viscerosomatic inhibition to thermal stimulation of the forepaw and hind paw. This inhibition was reversed, and the paw withdrawal latency was slightly decreased in neonatal (P3) carrageenan-treated rats. Rats treated on P14 appeared similar to naive rats. These data support the hypothesis that neonatal hind paw injury during a critical period permanently alters sensory processing of multiple sensory modalities in the adult. Animals develop with greater inhibitory processing of somatic and visceral stimuli throughout the neuraxis. However, inflammation in the adult in previously uninjured tissue reverses the hypoalgesia and evokes development of normal hyperexcitability associated with tissue injury. PERSPECTIVE: Trauma experienced by premature infants can lead to alterations in sensory processing throughout life. This study shows that short-term somatic tissue injury to neonatal rats during a well-defined critical period alters several aspects of viscerosensory processing in the adult, demonstrating that injury to one tissue affects sensory processing throughout the body.

Abnormalities in the dopamine system in schizophrenia may lie in altered levels of dopamine receptor-interacting proteins.

BACKGROUND: Dopamine receptor-interacting proteins constitute a part of the dopamine system that is involved in regulation of dopamine receptor-associated intracellular signaling. Previously, we demonstrated that two such proteins, the D1 receptor-interacting protein calcyon and the D2 receptor-interacting protein neuronal calcium sensor-1 (NCS-1), were elevated in the prefrontal cortex of schizophrenia cases from the Stanley Foundation Neuropathology Consortium. METHODS: The aim of this study was to confirm and expand these findings. We employed Western blot and real-time reverse transcriptase polymerase chain reaction analyses to compare prefrontal (area 46) and occipital (area 17) cortical levels of calcyon and NCS-1 proteins and mRNAs between schizophrenia (n = 37) and control (n = 30) cohorts from the Brain Collection of the Mount Sinai Medical School/Bronx Veterans Administration Medical Center. RESULTS: The schizophrenia cohort showed significant up-regulation of calcyon protein and message levels in both prefrontal and occipital cortical regions, both of which also displayed schizophrenia-associated up-regulation of NCS-1 message. Protein levels of NCS-1 were elevated only in the prefrontal cortex. All increases in protein levels were correlated with those of corresponding messages. Furthermore, schizophrenia-associated alterations in the levels of calcyon and NCS-1 messages were correlated. CONCLUSIONS: Up-regulation of calcyon and NCS-1 in the second schizophrenia cohort strengthens the proposition that abnormalities of the dopamine system in this disease may lie in altered levels of dopamine receptor-interacting proteins. Also, up-regulation of both calcyon and NCS-1 in the cortex of schizophrenia patients can be attributed largely to an enhanced transcription or reduced degradation of their messages. Finally, our findings suggest that elevations in the expressions of calcyon and NCS-1 in schizophrenia may have the same underlying cause.

Cerebral cortical abnormalities seen in a non-human primate model of prenatal cocaine exposure are not related to vasoconstriction.

In our previous studies [J. Comp. Neurol. 435 (2001) 263] we demonstrated that rhesus monkeys born to mothers receiving cocaine orally during the period of pregnancy when neurons destined for the cerebral neocortex were generated displayed inappropriate positioning of neocortical neurons, loss of normal neocortical lamination, and reduction in neocortical volume, density and total number of neocortical neurons. In the present paper, we examined whether these cytoarchitectural abnormalities were related to the relatively high blood levels of the cocaine metabolite, benzoylecgonine, associated with oral cocaine administration. We also evaluated the role of vasoconstriction of the uteroumbilical and fetal brain vessels in the generation of these abnormalities. For these purposes, we compared cerebral neocortical cytoarchitecture in 2-month-old monkeys from five groups of mothers: (1). a drug-naïve group, (2). a cocaine-treated group, (3). a group treated with benzoylecgonine at doses producing higher blood levels of this metabolite and stronger vasoconstriction that those in the cocaine-treated group, (4). a group treated with cocaine plus the vasodilator, isosorbide dinitrate, which counteracted the vasoconstrictive actions of cocaine, and (5). a group exposed to isosorbide dinitrate alone. All treatments were carried out from the 45 th through 102 nd day of pregnancy. We found that the general appearance of the neocortex and the position and number of neocortical neurons in the offspring of benzoylecgonine- and isosorbide dinitrate-treated mothers were indistinguishable from those in the offspring of drug-naïve mothers. In contrast, significant alterations in these parameters (similar to those seen in our previous studies) were observed in the offspring of cocaine and cocaine + isosorbide dinitrate-treated mothers. These findings suggest that it is unlikely that either benzoylecgonine or vasoconstriction are responsible for the abnormalities seen in the neocortical cytoarchitecture in our non-human primate model of prenatal cocaine exposure.

Neurobehavioral deficits in neonatal rhesus monkeys exposed to cocaine in utero.

In spite of significant efforts, the neurobehavioral deficits in infants born from cocaine-abusing mothers have not been clearly defined. In the present study, we examined the presence of these abnormalities in a rhesus monkey model of prenatal cocaine exposure using a nonhuman primate adaptation of the Neonatal Behavioral Assessment Scale (NBAS). Pregnant monkeys (n = 14) received 10 mg/kg cocaine twice a day orally (in fruit treats) from the 40th through 102nd postconception days (PCD40-PCD102), which is the period of cerebral cortical neuronogenesis (approximately second trimester). The control consisted of pregnant monkeys (n = 14) receiving fruit treats only. The animals were allowed to deliver vaginally at term (approximately PCD165). The first testing session was conducted on PCD171 (within the first week after birth); the second testing session was conducted on PCD177 (within the second week after birth); the third test was conducted on PCD183 (within the third week after birth); and the fourth testing session was conducted on PCD189 (within the fourth week after birth). The prenatally cocaine-exposed infants showed deficits in orientation, state control, and motor maturity, which were detectable during the second, third, and fourth testing sessions. The same testing sessions also revealed a significant reduction in the time devoted to toy manipulation, which points to impaired attention. None of these abnormalities were seen during the first testing session. The first session, however, revealed increased tremulousness (one of the indicators of autonomic stability) in the prenatally cocaine-exposed infants. This impairment disappeared by the third testing session. The present findings demonstrate the potential of prenatal cocaine exposure to induce neurobehavioral deficits detectable by NBAS-like testing in primate infants.

Optimization of the mechanical nociceptive threshold testing with the Randall-Selitto assay.

The Randall-Selitto (RS) assay is widely used for quantification of thresholds of the rat hindpaw withdrawal reflex to nociceptive pressure stimulation. Despite a report by Taiwo et al. [Brain Research 487 (1989)] that the sensitivity of the RS assay can be significantly improved by pre-training, many researchers still conduct this test in untrained rats. In part, this is because the study of Taiwo et al. employed heavily-restrained and thus very stressed animals. That study also examined bradykinin-induced hyperalgesia rather than hyperalgesia associated with persistent inflammatory models used in many other studies. Therefore, it is conceivable that pre-training may be unnecessary with a less restraining RS testing paradigm and the use of inflammation-producing agents. To resolve these issues, we re-examined the need for pre-training with the RS assay with minimal animal restraint and inflammation produced by Complete Freund's Adjuvant (CFA) injection. We also examined the sensitivity of this assay to detect analgesia induced by swim stress. We found that without training the differences between untreated, CFA-injected, swim stress-exposed, and CFA + swim stress-treated animal groups did not reach statistical significance. Four days of training, however, enlarged these differences to statistically significant levels. Furthermore, we found that the use of only the last measurement within a testing session, rather than the average of all collected measurements, may further enhance the sensitivity of the RS assay.

Calcium signaling dysfunction in schizophrenia: a unifying approach.

The present paper demonstrates a remarkable pervasiveness of underlying Ca(2+) signaling motifs among the available biochemical findings in schizophrenic patients and among the major molecular hypotheses of this disease. In addition, the paper reviews the findings suggesting that Ca(2+) is capable of inducing structural and cognitive deficits seen in schizophrenia. The evidence of the ability of antipsychotic drugs to affect Ca(2+) signaling is also presented. Based on these data, it is proposed that altered Ca(2+) signaling may constitute the central unifying molecular pathology in schizophrenia. According to this hypothesis schizophrenia can result from alterations in multiple proteins and other molecules as long as these alterations lead to abnormalities in certain key aspects of intracellular Ca(2+) signaling cascades.

Dopamine receptor-interacting proteins: the Ca(2+) connection in dopamine signaling.

Abnormal activity of the dopamine system has been implicated in several psychiatric and neurological illnesses; however, lack of knowledge about the precise sites of dopamine dysfunction has compromised our ability to improve the efficacy and safety of dopamine-related drugs used in treatment modalities. Recent work suggests that dopamine transmission is regulated via the concerted efforts of a cohort of cytoskeletal, adaptor and signaling proteins called dopamine receptor-interacting proteins (DRIPs). The discovery that two DRIPs, calcyon and neuronal Ca(2+) sensor 1 (NCS-1), are upregulated in schizophrenia highlights the possibility that altered protein interactions and defects in Ca(2+) homeostasis might contribute to abnormalities in the brain dopamine system in neuropsychiatric diseases.

Up-regulation of the D1 dopamine receptor-interacting protein, calcyon, in patients with schizophrenia.

BACKGROUND: The dopamine hypothesis remains a prominent influence on research into the pathogenesis of schizophrenia, yet the presence of consistent schizophrenia-linked abnormalities in the presynaptic components of the dopamine system or in dopamine receptors still remains a matter of debate. The present study focuses on a recently recognized group of dopamine receptor-interacting proteins as possible novel sites of dysfunction in schizophrenia. Specifically, we examined whether the D1 dopamine receptor-interacting protein calcyon and the D2 dopamine receptor-interacting proteins filamin-A and spinophilin are affected in the dorsolateral prefrontal cortex of patients with schizophrenia. METHODS: Slot blots of dorsolateral prefrontal cortical tissue were used to compare the levels of the 3 proteins of interest in control, schizophrenic, bipolar, and major depression groups (n = 15 per group). The nonschizophrenic psychiatric groups were included to determine the specificity of the detected abnormalities. RESULTS: The dorsolateral prefrontal cortex in schizophrenic patients displayed nearly twice the normal levels of calcyon, whereas filamin-A and spinophilin levels were unaltered. Patients with bipolar disorder or major depression showed no changes in all 3 proteins examined. CONCLUSION: Our findings provide the first evidence that abnormalities in the dopamine system of patients with schizophrenia may lie in altered levels of dopamine receptor-interacting proteins.

D1 dopamine receptors in the mouse prefrontal cortex: Immunocytochemical and cognitive neuropharmacological analyses.

Dopamine D1 receptors have critical neuromodulatory influences on the working memory functions of the prefrontal cortex, a brain region affected in many neuropsychiatric disorders. When D1 receptor agents are administered to rats or monkeys performing working memory tasks, an "inverted U" dose/response function is typically observed, whereby either too little or too much D1 receptor stimulation impairs working memory. There are two subtypes of D1 receptors, the D1A and the D1B (also known as the D1 and D5, respectively), but the relative contributions of these subtypes to prefrontal cortical function are not known, as there are no pharmacological agents that can distinguish between these receptors. Thus, genetically altered mice are needed to address this question. However, it is not known whether the mouse prefrontal cortex contains both D1A and D1B receptor subtypes, nor is it known whether mice will exhibit responses to D1 receptor agonists similar to those seen in rats and monkeys. The current study examined these issues by immunostaining the mouse brain with specific antibodies directed at the D1A and D1B receptor subtypes and by assessing the effects of increasing doses of a D1 receptor agonist, SKF81297, on spatial working memory performance in mice. Results indicate that mice are generally similar to monkeys and rats, expressing both D1A and D1B receptors in the prefrontal cortex and exhibiting an inverted "U" dose/response curve when administered SKF81297.

Up-regulation of neuronal calcium sensor-1 (NCS-1) in the prefrontal cortex of schizophrenic and bipolar patients.

The delineation of dopamine dysfunction in the mentally ill has been a long-standing quest of biological psychiatry. The present study focuses on a recently recognized group of dopamine receptor-interacting proteins as possible novel sites of dysfunction in schizophrenic and bipolar patients. We demonstrate that the dorsolateral prefrontal cortex in schizophrenia and bipolar cases from the Stanley Foundation Neuropathology Consortium display significantly elevated levels of the D2 dopamine receptor desensitization regulatory protein, neuronal calcium sensor-1. These levels of neuronal calcium sensor-1 were not influenced by age, gender, hemisphere, cause of death, postmortem period, alcohol consumption, or antipsychotic and mood stabilizing medications. The present study supports the hypothesis that schizophrenia and bipolar disorder may be associated with abnormalities in dopamine receptor-interacting proteins.

Consequences of prenatal cocaine exposure in nonhuman primates.

The extent to which cocaine abuse by pregnant women can affect development of their offspring remains a matter of significant debate. In large part, this is due to difficulties in accurate determination of the type, dose, and pattern of cocaine administration by drug abusing women as well as to difficulties in controlling for a wide range of potentially confounding variables, such as other drugs used, race, socioeconomic status, and level of prenatal care. On this background, examination of the effects of prenatal cocaine exposure in highly controlled nonhuman primate models represents an important complement to the human research. The present review summarizes the data obtained in several different rhesus monkey models of cocaine exposure in utero. These data demonstrate the potential of prenatal cocaine exposure to interfere with structural and biochemical development of the brain leading to behavioral deficits at birth and/or during adulthood. However, the differences in the outcomes between individual models also suggest that the specific types and severity of cocaine effects are likely dependent on the route, dose, gestational period, and daily pattern of administration.