Charles R. Neal

Localization of orphanin FQ (nociceptin) peptide and messenger RNA in the central nervous system of the rat

Orphanin FQ (OFQ) is the endogenous agonist of the opioid receptor‐like receptor (ORL‐1). It and its precursor, prepro‐OFQ, exhibit structural features suggestive of the opioid peptides. A cDNA encoding the OFQ precursor sequence in the rat recently has been cloned, and the authors recently generated a polyclonal antibody directed against the OFQ peptide. In the present study, the authors used in situ hybridization and immunohistochemistry to examine the distribution of OFQ peptide and mRNA in the central nervous system of the adult rat. OFQ immunoreactivity and prepro‐OFQ mRNA expression correlated virtually in all brain areas studied. In the forebrain, OFQ peptide and mRNA were prominent in the neocortex endopiriform nucleus, claustrum, lateral septum, ventral forebrain, hypothalamus, mammillary bodies, central and medial nuclei of the amygdala, hippocampal formation, paratenial and reticular nuclei of the thalamus, medial habenula, and zona incerta. No OFQ was observed in the pineal or pituitary glands. In the brainstem, OFQ was prominent in the ventral tegmental area, substantia nigra, nucleus of the posterior commissure, central gray, nucleus of Darkschewitsch, peripeduncular nucleus, interpeduncular nucleus, tegmental nuclei, locus coeruleus, raphe complex, lateral parabrachial nucleus, inferior olivary complex, vestibular nuclear complex, prepositus hypoglossus, solitary nucleus, nucleus ambiguous, caudal spinal trigeminal nucleus, and reticular formation. In the spinal cord, OFQ was observed throughout the dorsal and ventral horns. The wide distribution of this peptide provides support for its role in a multitude of functions, including not only nociception but also motor and balance control, special sensory processing, and various autonomic and physiologic processes. J. Comp. Neurol. 406:503–547, 1999.

Opioid receptor‐like (ORL1) receptor distribution in the rat central nervous system: Comparison of ORL1 receptor mRNA expression with 125I‐[14Tyr]‐orphanin FQ binding

The recently discovered neuropeptide orphanin FQ (OFQ), and its opioid receptor‐like (ORL1) receptor, exhibit structural features suggestive of the μ, κ, and δ opioid systems. The anatomic distribution of OFQ immunoreactivity and mRNA expression has been reported recently. In the present analysis, we compare the distribution of orphanin receptor mRNA expression with that of orphanin FQ binding at the ORL1 receptor in the adult rat central nervous system (CNS). By using in vitro receptor autoradiography with 125I‐[14Tyr]‐OFQ as the radioligand, orphanin receptor binding was analyzed throughout the rat CNS. Orphanin binding sites were densest in several cortical regions, the anterior olfactory nucleus, lateral septum, ventral forebrain, several hypothalamic nuclei, hippocampal formation, basolateral and medial amygdala, central gray, pontine nuclei, interpeduncular nucleus, substantia nigra, raphe complex, locus coeruleus, vestibular nuclear complex, and the spinal cord. By using in situ hybridization, cells expressing ORL1 mRNA were most numerous throughout multiple cortical regions, the anterior olfactory nucleus, lateral septum, endopiriform nucleus, ventral forebrain, multiple hypothalamic nuclei, nucleus of the lateral olfactory tract, medial amygdala, hippocampal formation, substantia nigra, ventral tegmental area, central gray, raphe complex, locus coeruleus, multiple brainstem motor nuclei, inferior olive, deep cerebellar nuclei, vestibular nuclear complex, nucleus of the solitary tract, reticular formation, dorsal root ganglia, and spinal cord. The diffuse distribution of ORL1 mRNA and binding supports an extensive role for orphanin FQ in a multitude of CNS functions, including motor and balance control, reinforcement and reward, nociception, the stress response, sexual behavior, aggression, and autonomic control of physiologic processes. J. Comp. Neurol. 412:563–605, 1999.

Mitochondrial-related gene expression changes are sensitive to agonal-pH state: implications for brain disorders

Mitochondrial defects in gene expression have been implicated in the pathophysiology of bipolar disorder and schizophrenia. We have now contrasted control brains with low pH versus high pH and showed that 28% of genes in mitochondrial-related pathways meet criteria for differential expression. A majority of genes in the mitochondrial, chaperone and proteasome pathways of nuclear DNA-encoded gene expression were decreased with decreased brain pH, whereas a majority of genes in the apoptotic and reactive oxygen stress pathways showed an increased gene expression with a decreased brain pH. There was a significant increase in mitochondrial DNA copy number and mitochondrial DNA gene expression with increased agonal duration. To minimize effects of agonal-pH state on mood disorder comparisons, two classic approaches were used, removing all subjects with low pH and agonal factors from analysis, or grouping low and high pH as a separate variable. Three groups of potential candidate genes emerged that may be mood disorder related: (a) genes that showed no sensitivity to pH but were differentially expressed in bipolar disorder or major depressive disorder; (b) genes that were altered by agonal-pH in one direction but altered in mood disorder in the opposite direction to agonal-pH and (c) genes with agonal-pH sensitivity that displayed the same direction of changes in mood disorder. Genes from these categories such as NR4A1 and HSPA2 were confirmed with Q-PCR. The interpretation of postmortem brain studies involving broad mitochondrial gene expression and related pathway alterations must be monitored against the strong effect of agonal-pH state. Genes with the least sensitivity to agonal-pH could present a starting point for candidate gene search in neuropsychiatric disorders.

Selective Serotonin Reuptake Inhibitor (SSRI) Use during Pregnancy and Effects on the Fetus and Newborn: A Meta-Analysis

Selective serotonin reuptake inhibitors (SSRIs) are frequently used to treat depression during pregnancy and the postpartum period. These drugs are capable of crossing the placenta and being transferred to the newborn during lactation. This report reviews the available information regarding the effects of SSRIs on the fetus and newborn; including long-term neurodevelopmental outcomes.

Transcriptional Profiling of the Developing Rat Brain Reveals That the Most Dramatic Regional Differentiation in Gene Expression Occurs Postpartum

Neural development involves the expression of ensembles of regulatory genes that control the coordinate and region-specific expression of a host of other genes, resulting in the unique structure, connectivity, and function of each brain region. Although the role of some specific genes in neural development has been studied in detail, we have no global view of the orchestration of spatial and temporal aspects of gene expression across multiple regions of the developing brain. To this end, we used transcriptional profiling to examine expression levels of 9955 genes in the hypothalamus, hippocampus, and frontal cortex across seven stages of postnatal development and up to four stages of prenatal development in individual male rats (six per group). The results reveal dramatic changes across development in >97% of the neurally expressed genes. They also uncover a surprising degree of regional differentiation occurring after birth and through the first 2 weeks of life. Cluster analysis identifies 20 clusters of transcripts enriched in genes related to particular functions, such as DNA metabolism, nuclear function, synaptic vesicle transport, myelination, and neuropeptide hormone activity. Thus, groups of genes with related functions change in the brain at specific times, possibly marking critical periods for each function. These findings can broadly serve as a backdrop for studying the role of individual genes in neural development. They also underscore the importance of early postnatal life in the rat, which corresponds to late gestation in the human, as a critical late phase of neural organization and differentiation, even in subcortical regions.

Expression of orphanin FQ and the opioid receptor-like (ORL1) receptor in the developing human and rat brain

The orphanin peptide system, although structurally similar to the endogenous opioid family of peptides and receptors, has been established as a distinct neurochemical entity. The distribution of the opioid receptor-like (ORL1) receptor and its endogenous ligand orphanin FQ (OFQ) in the central nervous system of the adult rat has been recently reported, and although diffusely disseminated throughout the brain, this neuropeptide system is particularly expressed within stress and pain circuitry. Little is known concerning the normal expression of the orphanin system during gestation, nor how opiate or stress exposure may influence its development. Using in situ hybridization techniques, the present study was undertaken to determine the normal pattern of expression of ORL1 mRNA in the human and rat brain at various developmental stages. Rat embryos, postnatal rat brains and postmortem human brains were collected, frozen and cut into 15 microm coronal sections. In situ hybridization was performed using riboprobes generated from cDNA containing representative human and rat ORL1 and OFQ sequences. Both ORL1 and OFQ mRNA is detected as early as E12 in the cortical plate, basal forebrain, brainstem and spinal cord. Expression for both ORL1 and OFQ is strongest during the early postnatal period, remaining strong in the spinal cord, brainstem, ventral forebrain, and neocortex into the adult. Human ORL1 and OFQ expression is observed at 16 weeks gestation, remaining relatively unchanged up to 36 weeks. The influence of early orphanin expression on maturation of stress and pain circuitry in the developing brain remains unknown.

Nociceptin/orphanin FQ and opioid receptor-like receptor mRNA expression in dopamine systems

Although nociceptin/orphanin FQ (N/OFQ) influences dopamine (DA) neuronal activity, it is not known whether N/OFQ acts directly on DA neurons, indirectly by means of local circuitry, or both. We used two parallel approaches, dual in situ hybridization (ISH) and neurotoxic lesions of DA neurons by using 6‐hydroxydopamine (6‐OHDA), to ascertain whether N/OFQ and the N/OFQ receptor (NOP) mRNA are expressed in DA neurons in the ventral tegmental area (VTA) and substantia nigra compacta (SNc). In the VTA and SNc, small populations (∼6–10%) of N/OFQ‐containing neurons coexpressed mRNA for tyrosine hydroxylase (TH), the rate‐limiting enzyme for DA synthesis. Similarly, very few (1–2%) TH‐positive neurons contained N/OFQ mRNA signal. A majority of NOP‐positive neurons (∼75%) expressed TH mRNA and roughly half of the TH‐containing neurons expressed NOP mRNA. Many N/OFQ neurons (∼50–60%) expressed glutamic acid decarboxylase 65 and 67 mRNAs, markers for γ‐aminobutyric acid (GABA) neurons. In the 6‐OHDA lesion studies, NOP mRNA levels were nearly 80 and 85% lower in the VTA and SNc, respectively, on the lesioned side. These lesions appear to lead to compensatory changes, with N/OFQ mRNA levels approximately 60% and 300% higher in the VTA and SNc, respectively, after 6‐OHDA lesions. Finally, N/OFQ‐stimulated [35S]guanylyl‐5′‐O‐(γ‐thio)‐triphosphate levels were decreased in the VTA and SNc but not the prefrontal cortex after 6‐OHDA lesions. Accordingly, it appears that N/OFQ mRNA was found largely on nondopaminergic (i.e., GABA) neurons, whereas NOP mRNA was located on DA neurons. N/OFQ is in a position to influence DA neuronal activity by means of the NOP located on DA neurons. J. Comp. Neurol. 444:358–368, 2002.

Prenatal Methamphetamine Exposure and Childhood Behavior Problems at 3 and 5 Years of Age

OBJECTIVE: We evaluated behavior problems in children who were prenatally exposed to methamphetamine (MA) at ages 3 and 5 years. METHODS: The Infant Development, Environment, and Lifestyle study, a prospective, longitudinal study of prenatal MA exposure and child outcome, enrolled subjects postpartum in Los Angeles, California; Honolulu, Hawaii; Des Moines, Iowa; and Tulsa, Oklahoma. Prenatal exposure was determined by maternal self-report and/or meconium results. Exposed and comparison groups were matched on race, birth weight, public health insurance, and education. Mothers in the comparison group denied use and had a negative meconium screen for amphetamines. Prenatal exposures to tobacco, alcohol, or marijuana occurred in both groups. At ages 3 and 5 years, 330 children (166 exposed and 164 comparison) were assessed for behavior problems by using the caregiver report on the Child Behavior Checklist. General linear mixed models were used to determine the effects of prenatal MA exposure, including heavy exposure (≥3 days per week), age, and the interaction of exposure and age on behavior problems with adjustment for other drugs of abuse and environmental risk factors. RESULTS: MA exposure was associated with increased emotional reactivity and anxious/depressed problems at both ages and externalizing and attention-deficit/hyperactivity disorder problems by age 5 years. Heavy exposure was related to attention problems and withdrawn behavior at both ages. There were no effects of MA on the internalizing or total behavior problems scales. CONCLUSIONS: This first report of behavior problems in patients as young as 3 years associated with MA exposure identifies an important public health problem. Continued follow-up can inform the development of preventive intervention programs.

Depressive Symptoms During Pregnancy: Impact on Neuroendocrine and Neonatal Outcomes

OBJECTIVE To explore the interplay of maternal depressive symptoms on the infant limbic-hypothalamic-pituitary axis (LHPA) and neurological development. DESIGN Pregnant women were monitored for depressive symptoms using the Beck Depression Inventory (BDI) at 28, 32, and 37 weeks of gestation and at delivery. A mixture growth curve analysis divided the women into three risk groups: low/stable, intermediate, and high/increasing depression based on BDI scores. The infant neuroendocrine system was examined using cord blood for adrenocorticotrophic hormone (ACTH) and cortisol measurements. Two-week-old infants were examined using Neonatal Intensive Care Unit Neurobehavioral Scale (NNNS). RESULTS Infants born to women of the high/increasing depression group had significant ACTH elevation at birth. On NNNS examination, these infants were more hypotonic and habituated to auditory and visual stimuli. CONCLUSION When compared to non-depressed women, maternal depressive symptoms, even in the absence of major depressive disorder, appeared to facilitate a different developmental pathway for the infant LHPA and early neurological development.

Comparative study of clinical pulmonary surfactants using atomic force microscopy.

Clinical pulmonary surfactant is routinely used to treat premature newborns with respiratory distress syndrome, and has shown great potential in alleviating a number of neonatal and adult respiratory diseases. Despite extensive study of chemical composition, surface activity, and clinical performance of various surfactant preparations, a direct comparison of surfactant films is still lacking. In this study, we use atomic force microscopy to characterize and compare four animal-derived clinical surfactants currently used throughout the world, i.e., Survanta, Curosurf, Infasurf and BLES. These modified-natural surfactants are further compared to dipalmitoyl phosphatidylcholine (DPPC), a synthetic model surfactant of DPPC:palmitoyl-oleoyl phosphatidylglycerol (POPG) (7:3), and endogenous bovine natural surfactant. Atomic force microscopy reveals significant differences in the lateral structure and molecular organization of these surfactant preparations. These differences are discussed in terms of DPPC and cholesterol contents. We conclude that all animal-derived clinical surfactants assume a similar structure of multilayers of fluid phospholipids closely attached to an interfacial monolayer enriched in DPPC, at physiologically relevant surface pressures. This study provides the first comprehensive survey of the lateral structure of clinical surfactants at various surface pressures. It may have clinical implications on future application and development of surfactant preparations.