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U H Winzer-Serhan

Publications and source records attributed to U H Winzer-Serhan.

11 recordsLinked to original sources
PubMed2006

Chronic neonatal nicotine upregulates heteromeric nicotinic acetylcholine receptor binding without change in subunit mRNA expression.

Smoking during pregnancy chronically exposes the fetus to nicotine resulting in long-term behavioral and cognitive deficits. Nicotine binds to neuronal nicotinic acetylcholine receptors (nAChRs), pentameric ligand-gated ion channels widely expressed in the nervous system. Chronic nicotine upregulates high-affinity nAChRs in animals and smokers. Here we determined if chronic nicotine treatment during a developmental period corresponding to the human third trimester regulates nAChR expression. Rat pups were intubated orally three times per day with or without nicotine (6 mg/kg/day) from postnatal day 1 to 8. Subunit mRNA expression was assessed by in situ hybridization. Expression of heteromeric and homomeric nAChR receptor was evaluated by autoradiography using (125)I-epibatidine and (125)I-alphabungarotoxin, respectively. nAChR expression was analyzed in cortex, hippocampus, thalamus and medial habenula from autoradiograms using computer assisted image analysis. Nicotine induced significant upregulation of heteromeric but not homomeric nAChRs in hippocampus, cortex and thalamus without changes in subunit mRNA expression. No effect of chronic nicotine on receptor expression was detected in the medial habenula, suggesting that nicotine's effect was mainly on alpha4beta2-type heteromeric nAChRs. The nicotine-induced upregulation was reversed after nicotine withdrawal. Receptor blockade by DHbetaE, an antagonist for heteromeric alpha4/beta2 nAChRs, did not prevent upregulation but increased expression to a similar degree as nicotine. Combination of both drugs had a cumulative effect. Thus, although transient, intermittent nicotine exposure as seen in smoking mothers is sufficient to upregulate heteromeric nAChRs during a critical period of brain development and could contribute to the behavioral deficits found in children whose mother smoked.

Age Factors↗
PubMed1999

Expression of alpha2A adrenoceptors during rat neocortical development.

Norepinephrine has been suggested to play a neurotrophic role during development and is present in the brain as early as embryonic day (E) 12. We have recently demonstrated that the alpha2A adrenoceptor subtype is widely expressed during times of neuronal migration and differentiation throughout the developing brain. Here, we report the temporal and spatial expression pattern of alpha2A adrenoceptors in neocortex during late embryonic and early postnatal development using in situ hybridization and receptor autoradiography. Functional alpha2 receptors in embryonic rat cortex were also detected using agonist stimulated [35S]GTPgammaS autoradiography. Both alpha2A mRNA and protein expression were strongly increased by E19 and E20, respectively. The increased expression was in the cortical plate and intermediate and subventricular zones, corresponding to tiers of migrating and differentiating neurons. This transient up-regulation of alpha2A adrenoceptors was restricted to the lateral neocortex. At E20, functional alpha2 adrenoceptors were also detected in deep layers of lateral neocortex. During the first week of postnatal development, the expression of alpha2A mRNA and protein changed markedly, giving rise to a more mature pattern of anatomical distribution. The temporal and spatial distribution of alpha2A adrenoceptors in developing neocortex is consistent with expression of functional proteins on migrating and differentiating layer IV to II neurons. These findings suggest that alpha2A receptors may mediate a neurotrophic effect of norepinephrine during fetal cortical development. The early delineation of the lateral neocortex, which will develop into somatosensory and auditory cortices, suggests an intrinsic regulation of alpha2A mRNA expression.

Adrenergic alpha-Agonists↗
PubMed1999

Highly sensitive radioactive in situ hybridization using full length hydrolyzed riboprobes to detect alpha 2 adrenoceptor subtype mRNAs in adult and developing rat brain.

The mRNA expression of highly homologous alpha 2 adrenoceptor subtypes was determined using a highly sensitive in situ hybridization protocol that allowed the detection of low abundance mRNA. Full-length 35S-labeled riboprobes specific for alpha 2A, alpha 2B and alpha 2C adrenoceptors were used for maximal sensitivity. The probes were hydrolyzed to an average length of 600 bp which, in combination with proteinase K digestion, resulted in optimal probe penetration in developmental and adult tissue. The expression intensity could be quantified and the ontogeny of receptor mRNA expression determined. At the same time receptor binding sites or functional proteins could be detected simultaneously in adjacent sections, because fresh frozen and post-fixed tissue was used.

Animals↗
PubMed1998

Opioid receptor and peptide mRNA expression in proliferative zones of fetal rat central nervous system.

There is increasing evidence to suggest that opioid peptides may have widespread effects as regulators of growth. To evaluate the hypothesis that endogenous opioids control cellular proliferation during neural development, we have used in situ hybridization to examine opioid peptide and receptor mRNA expression in neuroepithelial zones of fetal rat brain and spinal cord. Our data show that proenkephalin mRNA is widely expressed in forebrain germinal zones and choroid plexus during the second half of gestation. In contrast, prodynorphin mRNA expression is restricted to the periventricular region of the ventral spinal cord. Little mu or delta receptor mRNA expression was detected in any regions of neuronal proliferation prior to birth. However, kappa receptor mRNA is widely expressed in hindbrain germinal zones during the 3rd week of gestation. Our present findings support the hypothesis that endogenous opioids may regulate proliferation of both neuronal and non-neuronal cells during central nervous system development. Given the segregated expression of proenkephalin mRNA in forebrain neuroepithelium and kappa receptor mRNA within hindbrain, different opioid mechanisms may regulate cell division in rostral and caudal brain regions.

Animals↗
PubMed1997

Codistribution of nicotinic acetylcholine receptor subunit alpha3 and beta4 mRNAs during rat brain development.

We have used in situ hybridization to characterize the ontogeny of alpha3 and beta4 nicotinic acetylcholine receptor (nAChR) subunit mRNA expression in rat brain. Transcripts for both subunits were detected in embryonic brain, although overlapping expression of alpha3 mRNA was only evident in areas of strong beta4 mRNA expression, including the medial habenula, locus coeruleus, the cerebellar primordium, and several motor and sensory brainstem nuclei. During the perinatal period, the independent expression of alpha3 mRNA declined, and greater correspondence in the temporal and spatial expression of alpha3 and beta4 subunit mRNAs emerged. In general, beta4 mRNA expression preceded that of alpha3 mRNA by 1 to 2 days. Overlapping expression patterns were transiently detected in the caudate putamen, basal forebrain, frontal and visual cortices, and in the CA3 field of hippocampus. Codistribution that lasted throughout development and into adulthood was noted in a number of brain areas, including the retrosplenial cortex, subiculum, medial habenula, interpeduncular nucleus, locus coeruleus, and brainstem motor nuclei. In many of these regions, alpha5 subunit mRNA was also expressed. Colocalization of alpha3 and beta4 mRNAs with choline acetyltransferase mRNA was detected in cholinergic neurons of the brainstem motor nuclei, nucleus ambiguus, dorsal motor nucleus of the vagus, motor trigeminal nucleus, and facial nucleus, but not in most forebrain cholinergic cells. The extensive correspondence in temporal and spatial distribution of alpha3 and beta4 mRNAs throughout postnatal brain development suggests that these subunits may be coordinately regulated and may form functional neuronal nAChRs with significant developmental roles.

Animals↗
PubMed1997

Alpha2B adrenoceptor mRNA expression during rat brain development.

The expression of alpha2B adrenoceptor mRNA in developing and adult rat brain was examined, using in situ hybridization with S-labeled riboprobes. In the adult we have detected more widespread expression than previously reported, with moderate to strong hybridization signals in the fundus striati, olfactory tubercles, septum, thalamus and Purkinje cells of the cerebellum. In addition, there was low expression in the endopiriform nucleus, claustrum, cortex, caudate-putamen and spinal trigeminal nucleus of the brain stem. During embryonic development, there was intense, transient mRNA expression in the developing vascular plexus and vasculature which disappeared by birth. In most brain areas which exhibit mRNA expression in the adult, expression started during late embryonic development; with the exception of the thalamus, where expression was differentially regulated in sensory and non-sensory thalamic nuclei starting at the end of the first postnatal week. In addition, there was transiently upregulated expression in the caudate-putamen and cerebellar Purkinje cells during late embryonic and early postnatal development, respectively. This transient expression correlates with the time of neuronal migration and differentiation in these structures and complements the developmental expression of alpha2A and alpha2C adrenoceptors. These results suggest that alpha2B adrenoceptors may play a role in angiogenesis and in mediating neurotrophic functions of norepinephrine in some brain areas.

Aging↗
PubMed1997

Expression of alpha 2 adrenoceptors during rat brain development--I. Alpha 2A messenger RNA expression.

The distribution of alpha 2A adrenoceptor messenger RNA expression in developing rat brain was characterized using in situ hybridization with 35S-labeled riboprobes. Intense hybridization signal was detected as early as embryonic day 14 in several areas adjacent to the forebrain and hindbrain germinal zones and in central noradrenergic neurons. A marked increase in messenger RNA expression was observed throughout the brain during late prenatal development, consistent with the migration and maturation of neurons in developing brain structures. In embryonic brain, there was a temporal and spatial correspondence in the appearance of alpha 2A messenger RNA expression and binding sites labeled with [3H]idazoxan or p-[125I]iodoclonidine, indicating translation into receptor protein at an early stage of development. Whereas the presynaptic expression remained constant throughout development, there was an early postnatal decline of alpha 2A receptor expression in many brain regions, including the olfactory bulb, cortex, caudate-putamen, hippocampus, thalamus, hypothalamus and medulla. Thereafter, messenger RNA expression increased, establishing an adult-like pattern during the second postnatal week, but remained low in areas such as the caudate-putamen, thalamus and hippocampus, which do not exhibit extensive expression in the adult. The transient perinatal expression of this alpha 2 adrenoceptor type, which coincides with a period of hyperreactivity to sensory stimuli in the locus coeruleus, may indicate a specific functional role for the alpha 2A receptor in the developing rat brain. The early and intense expression in olfactory structures suggests an involvement in early olfactory learning. The pattern of widespread, transient expression of alpha 2A receptors in the fetal brain is in marked contrast to the postnatal development of the alpha 2C receptor type.

Aging↗
PubMed1997

Expression of alpha 2 adrenoceptors during rat brain development--II. Alpha 2C messenger RNA expression and [3H]rauwolscine binding.

The distributions of alpha 2C adrenoceptor messenger RNA and high-affinity [3H]rauwolscine binding sites were characterized in developing rat brain. Using in situ hybridization with 35S-labeled riboprobes directed against the third intracellular loop, alpha 2C messenger RNA expression appeared in an adult-like pattern during the first and second postnatal weeks, in the anterior olfactory nucleus, caudate-putamen, olfactory tubercles, islands of Calleja and hippocampus, following the time-course of maturation of these structures. Only in the cerebellum was alpha 2C messenger RNA transiently expressed during the critical period of granule cell development. High-affinity [3H]rauwolscine binding sites were detected using receptor autoradiography and revealed a similar spatial and temporal time-course of appearance during rat brain development. The highest numbers of binding sites were detected in the olfactory tubercles and islands of Calleja, and moderate numbers in the anterior olfactory nucleus, caudate-putamen and hippocampus. Like alpha 2C messenger RNA expression, high-affinity [3H]rauwolscine binding sites were transiently expressed in the cerebellum. In some areas (e.g., the substantia nigra), [3H]rauwolscine binding sites were detected even though alpha C2 messenger RNA expression was absent. The strong spatial and temporal correspondence between messenger RNA expression and radioligand binding supports the conclusion that [3H]rauwolscine selectively labels alpha 2C adrenoceptors in the rat brain. The developmental pattern which was observed is in marked contrast to the early, transient expression of the alpha 2A adrenoceptor. Thus, the alpha 2A and alpha 2C receptor types may serve distinct functional roles in the developing brain.

Animals↗
PubMed1997

Glial regulation of alpha 7-type nicotinic acetylcholine receptor expression in cultured rat cortical neurons.

Primary embryonic cortical cultures were used as an in vitro model to evaluate the influence of glia on developmental expression of alpha 7-type nicotinic acetylcholine receptors in rat brain. In cells cultured in serum-containing medium without mitotic inhibitors, specific 125I-alpha-bungarotoxin binding to alpha 7-type nicotinic receptors was maximal 4-8 days after plating. Treatment with 5'-fluorodeoxyuridine (80 microM) from 1 to 3 days in vitro significantly reduced glial proliferation and concomitantly increased 125I-alpha-bungarotoxin binding, whereas plating onto a glial bed layer decreased binding. There was no significant binding to pure glial cultures. Treatment-induced changes in neuronal binding resulted from alterations in receptor density, with no change in affinity. 5'-Fluorodeoxyuridine treatment also increased cellular expression of alpha 7 receptor mRNA but had no effect on N-[3H]methylscopolamine binding to muscarinic receptors. Glial conditioned medium decreased 125I-alpha-bungarotoxin binding in both control and 5'-fluorodeoxyuridine-treated cultures, suggesting the release of a soluble factor that inhibits alpha 7-type nicotinic receptor expression. An additional mechanism of glial regulation may involve removal of glutamate from the surrounding medium, as added glutamate (200 microM) increased 125I-alpha-bungarotoxin binding in astrocyte-poor cultures but not in those that were astrocyte enriched. These results suggest that glia may serve a physiological role in regulating alpha 7-type nicotinic receptors in developing brain.

Animals↗
PubMed1993

Isolation and characterization of mouse monoclonal antibodies against a human vascular endothelial cell-specific antigen.

A murine hybridoma clone was isolated secreting IgG-antibodies specific for human vascular endothelial cells. The antibody recognized a plasma membrane antigen (designated HECMA-112) of an apparent molecular weight of 112,000. Indirect immunofluorescence with cultured endothelial cells showed a staining pattern clearly distinct from previously described endothelial cell-specific antigens. The antibody bound to untreated as well as ethanol-fixed, confluent human umbilical vein endothelial cells (HUVEC) but not to other human primary cells (corneal endothelial cells, fibroblasts, keratocytes, lymphocytes, thrombocytes, or erythrocytes) or endothelial cells isolated from bovine or porcine aorta. HECMA-112 can be regarded as an additional marker for human vascular endothelial cells in vivo and in vitro.

Animals↗