Conformational ensembles: the role of neuropeptide structures in receptor binding.

Conformational properties of several similar FMRFamide-like neuropeptides from mollusks were investigated by nuclear magnetic resonance (NMR) spectroscopy. It was found that amino acid substitutions in the N-terminal variable regions of the peptides had dramatic effects on the populations of reverse turns in solution. The populations of turns, as measured by two independent NMR parameters, were found to be highly correlated (r(2) = 0.

Circadian regulation of iodopsin and clock is altered in the retinal degeneration chicken retina.

We are interested in determining if the visual phototransduction cascade plays a role in light entrainment of photoreceptor circadian oscillators. In this study, we compared mRNA levels of iodopsin and the chicken homolog of Clock (cClock) in the retinas of normal and rd (retinal degeneration) chickens that lack functional rod and cone phototransduction cascades. Iodopsin is a circadian-regulated, photoreceptor-specific gene expressed in chicken retina, and Clock is a transcription factor that has been shown to play a role in the circadian clock mechanism in mouse and Drosophila.

Neurobiology of tobacco smoking and other addictive disorders.

Advances in research of the neurobiology of addictive disorders have provided clinicians with an evolving perspective on addiction. All drugs of abuse seem to share a common neurobiologic substrate involving the mesocorticolimbic system. Considerable evidence shows that these dopaminergic projections are involved in the positive brain reward, which drives addictive disorders; however, recent studies also implicate the neurotransmitters glutamate and serotonin in learning and sensitization to drug use.

Contributions of viral splice sites and cis-regulatory elements to lentivirus vector function.

The mobile transgene constructs of most human immunodeficiency virus (HIV)-based lentivirus vectors currently in use contain viral long terminal repeats, a 5' untranslated region, gag sequences, and env sequences that include the Rev-responsive element (RRE). In this study, we examined the possibility of deleting HIV splice sites and gag and env sequences from an HIV type 1 recombinant vector established in our laboratory as part of our ongoing efforts to improve this vector system. Mutations in the major splice donor site (SD) markedly reduced viral RNA expression but had little effect on vector titer.

Effects of assisted feeding on Wobbler mouse motoneuron disease and on serotonergic and peptidergic sprouting in the cervical spinal ventral horn.

The Wobbler mouse is used as a model of human motoneuron disease (MND). During the disease progress, the significant loss of motoneurons in cervical spinal cord and cranial motor nuclei leads to the progressive loss of motor function in the forelimb, head, and neck regions. The loss of cutting and chewing ability that results in the inability to feed properly might lead to a lower mean body weight (b.

Mapping of semantic, phonological, and orthographic verbal working memory in normal adults with functional magnetic resonance imaging.

Twelve neurologically normal participants (4 men and 8 women) performed semantic, phonological, and orthographic working memory tasks and a control task during functional magnetic resonance imaging. Divergent regions of the posterior left hemisphere used for decoding and storage of information emerged in each working memory versus control task comparison. These regions were consistent with previous literature on processing mechanisms for semantic, phonological, and orthographic information.

Analysis of murine Snrpn and human SNRPN gene imprinting in transgenic mice.

The SNRPN gene is known to be expressed exclusively from the paternal allele and to map to the critical region for the neurobehavioral disorder, Prader-Willi syndrome (PWS). As a means to investigate the mechanism of imprinting for the SNRPN gene, we have sought to recapitulate the imprinted expression of the endogenous gene. Using an 85-kb murine Snrpn clone, containing 33 kb of 5' and 30 kb of 3' flanking DNA, we obtained two intact transgenic lines.

Mechanisms of genomic imprinting.

A small number of mammalian genes undergo the process of genomic imprinting whereby the expression level of the alleles of a gene depends upon their parental origin. In the past year, attention has focused on the mechanisms that determine parental-specific expression patterns. Many imprinted genes are located in conserved clusters and, although it is apparent that imprinting of adjacent genes is jointly regulated, multiple mechanisms among and within clusters may operate.

Vitamin E and beta-carotene protect against ethanol combined with ischemia in an embryonic rat hippocampal culture model of fetal alcohol syndrome.

Neurodevelopmental damage can occur as a result of in utero exposure to alcohol. Oxidative stress processes are one of many proposed mechanisms thought to contribute to nervous system dysfunction characterized in fetal alcohol syndrome (FAS). Therefore, this study examined neuroprotective effects of antioxidant supplementation during ethanol (EtOH) treatment (0, 200, 400, 800 or 1600 mg/dl) combined with concomitants of EtOH exposure: acute (2-h) ischemia (aISCH) and chronic (16-h) hypoglycemia (cHG).

Role of phosphatidylinositol 3-kinase in angiotensin II regulation of norepinephrine neuromodulation in brain neurons of the spontaneously hypertensive rat.

Chronic stimulation of norepinephrine (NE) neuromodulation by angiotensin II (Ang II) involves activation of the Ras-Raf-MAP kinase signal transduction pathway in Wistar Kyoto (WKY) rat brain neurons. This pathway is only partially responsible for this heightened action of Ang II in the spontaneously hypertensive rat (SHR) brain neurons. In this study, we demonstrate that the MAP kinase-independent signaling pathway in the SHR neuron involves activation of PI3-kinase and protein kinase B (PKB/Akt).

BDNF and NGF afford in vitro neuroprotection against ethanol combined with acute ischemia and chronic hypoglycemia.

Consumption of alcohol during pregnancy can result in central nervous system deficits in infants ranging from fetal alcohol effects to fetal alcohol syndrome. Changes in cerebral metabolism causing ischemic in utero conditions can also result from ethanol (EtOH). Growth factors have been shown to ameliorate ischemic damage and EtOH-induced neurotoxicity.

Increase in fiber density for immunoreactive serotonin, substance P, enkephalin and thyrotropin-releasing hormone occurs during the early presymptomatic period of motoneuron disease in Wobbler mouse spinal cord ventral horn.

The Wobbler mouse is a useful small animal model for the study of human motoneuron diseases. Besides showing the loss of motoneurons when the symptoms are expressed around the age of 3 weeks, we have also demonstrated the presumed 'sprouting' of neuronal processes in the cervical spinal ventral horn which contain immunoreactive (IR) serotonin (5-HT), substance P (SP) and methionine and leucine enkephalins (ME, LE), as well as thyrotropin-releasing hormone (TRH). This occurs during the symptomatic period when IR-5-HT, ME and LE sprout at Stage 1, around the age of 3 weeks, whereas IR-SP sprouts only at a late stage (stage 4) of the disease (at age 3 months).

Interacting appetite-regulating pathways in the hypothalamic regulation of body weight.

Various aspects of the complex spatio-temporal patterning of hypothalamic signaling that leads to the development of synchronized nocturnal feeding in the rat are critically examined. Undoubtedly, as depicted in Fig. 7, a distinct ARN in the hypothalamus is involved in the control of nocturnal appetite.

The effect of ouabain on water diffusion in the rat hippocampal slice measured by high resolution NMR imaging.

High resolution NMR imaging of the isolated perfused rat hippocampal slice was used to quantitate ADC changes following ouabain-induced cell swelling. Hippocampal slices were studied in artificial cerebrospinal fluid and then in ouabain using a 600-MHz narrow bore spectrometer and a home-built perfusion chamber. The brain slices demonstrated biexponential diffusion behavior.

Neurotrophic factors BDNF and GDNF protect embryonic chick spinal cord motoneurons from ethanol neurotoxicity in vivo.

Maternal consumption of ethanol is widely recognized as a leading cause of mental and physical deficits. Many populations of the central nervous system are affected by the teratogenic effects of ethanol. Neurotrophic factors (NTFs) have been shown to protect against ethanol neurotoxicity in culture, although there have been no demonstrations of such protection in vivo, in specific neuronal populations.

Influence of pulse oximetry and capnography on time to diagnosis of critical incidents in anesthesia: a pilot study using a full-scale patient simulator.

Objective: Many studies (outcome, epidemiological) have tested the hypothesis that pulse oximetry and capnography affect the outcome of anesthetic care. Uncontrollable variables in clinical studies make it difficult to generate statistically conclusive data. In the present study, we eliminated the variability among patients and operative procedures by using a full-scale patient simulator.

Cytokine transcripts expressed by microglia in vitro are not expressed by ameboid microglia of the developing rat central nervous system.

Because of morphological similarities between ameboid microglia in the developing central nervous system (CNS), brain macrophages in the injured CNS, and cultured microglia in vitro, it is thought that these cell types are functionally equivalent. To investigate the validity of this assumption, we have compared mRNA levels of interleukin-1alpha and -1beta (IL-1alpha and IL-1beta), tumor necrosis factor-alpha and -beta (TNF-alpha and TNF-beta), transforming growth factor-beta1 (TGF-beta1), and macrophage colony-stimulating factor (M-CSF) in the postnatal day 4 (P4) supraventricular corpus callosum (SVCC) with those in unstimulated cultured microglia. Control tissues included spleen, cortex, hippocampus, and cerebellum.

Disruption of neural signaling within the hypothalamic ventromedial nucleus upregulates galanin gene expression in association with hyperphagia: an in situ hybridization analysis.

Hypothalamic neuropeptides play critical roles in the regulation of appetite and body weight. We recently reported that disruption of neural signaling in the ventromedial nucleus (VMN) by microinjection of the neurotoxin, colchicine (COL), produced transient hyperphagia with attendant body weight gain lasting for 4 days. The neural mechanism(s) underlying this temporary shift in energy homeostasis is still unknown.

Bcl-2 overexpression protects the neonatal cerebellum from ethanol neurotoxicity.

The developing nervous system is extremely sensitive to ethanol, and exposure often produces a condition known as the fetal alcohol syndrome. Although mechanisms underlying developmental ethanol toxicity have long been sought, they remain poorly understood. In this study, we examined the ability of the cell death repressor gene bcl-2 to protect against ethanol neurotoxicity.

Angiotensin II type 2 receptor-mediated apoptosis of cultured neurons from newborn rat brain.

Angiotensin II (Ang II) type 2 (AT2) receptors are highly expressed in neonate brain and may have a role in developmental processes such as apoptosis. Concurrent activation of c-Jun N-terminal kinase (JNK) and inhibition of Erk mitogen-activated protein kinase activities is important for apoptosis in many cells, and we previously demonstrated that stimulation of AT2 receptors causes decreased mitogen-activated protein kinase activity in neurons cultured from newborn rat hypothalamus and brain stem. Using such cultures we have employed terminal deoxynucleotidyl transferase-mediated deoxy-UTP nick end labeling and internucleosomal DNA fragmentation to assess the role of AT2 receptors in neuronal apoptosis.

Degradation of chondroitin sulfate proteoglycan enhances the neurite-promoting potential of spinal cord tissue.

The contribution of chondroitin sulfate proteoglycan (CSPG) in the suppression of axonal growth in rat spinal cord has been examined by means of an in vitro bioassay in which regenerating neurons are grown on tissue section substrata. Dissociated embryonic chick dorsal root ganglionic neurons were grown on normal and injured adult spinal cord tissue sections treated with chondroitinases. Neuritic growth on normal spinal cord tissue was meager.

A novel behavioral method to detect motoneuron disease in Wobbler mice aged three to seven days old.

The Wobbler mouse possesses an inherited autosomal recessive form of motoneuron disease. The most characteristic abnormality is the degeneration of motoneurons, mostly in the cervical spinal cord, and in the brain stem cranial motor nuclei. The underlying pathology shows up as symptoms that are only detectable confidently around the time of weaning (age 3 weeks).

Characterization of a primary central nervous system atypical teratoid/rhabdoid tumor and derivative cell line: immunophenotype and neoplastic properties.

Primary central nervous system (CNS) atypical teratoid/malignant rhabdoid tumors (ATT/RhT) occur during early childhood and are almost invariably fatal. Expression of multiple phenotypes in ATT/RhT suggests the presence of an undifferentiated progenitor with the potential to differentiate along multiple lines. These properties have made it difficult to characterize the etiology and histogenesis of these tumors and complicate efforts to develop targeted therapies.

Diurnal rhythm in cyclic GMP/nitric oxide efflux in the medial preoptic area of male rats.

Since nitric oxide (NO) is implicated in the neuroendocrine control of luteinizing hormone-releasing hormone (LHRH) secretion and sexual behavior which show diurnal variations, we monitored cGMP levels (an index of NO activity) in the extracellular compartment of the medial preoptic area (MPOA) using microdialysis. It was observed that MPOA cGMP levels rose significantly in the afternoon in both castrated and intact male rats, thereby suggesting the existence of a diurnal rhythm in MPOA cGMP/NO efflux which may participate in eliciting the well-known diurnal variations in LHRH neuronal activity and male sexual behavior.

Prenatal ethanol exposure reduces parvalbumin-immunoreactive GABAergic neuronal number in the adult rat cingulate cortex.

The effect of prenatal ethanol exposure on the number of parvalbumin-immunoreactive (PA+) GABAergic neurons in the adult rat anterior cingulate cortex was determined. Pregnant Long-Evans rats were maintained on one of three diets throughout gestation: an ethanol-containing liquid diet, a similar, control liquid diet with the isocaloric substitution of sucrose for ethanol, or a lab chow control diet. Offspring were euthanized on postnatal day 60 and brains were prepared for parvalbumin immunocytochemistry.