ISSN:0360-4012    

DOI:10.1002/jnr.490170102

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1987

数据来源: WILEY

摘要:

AbstractTyrosine hydroxylase (TH) is the rate‐limiting enzyme in the synthesis of catecholamines in neural tissues and adrenal medulla. To study the expression of the TH gene and its regulation in adult and developing neural tissues, we have synthesized an oligodeoxyribonucleotide probe (oligomer) that is specific for TH mRNA. Using Northern blot hybridization of polyadenylated RNAs from adrenal gland, brain stem, liver, and cerebral cortex with the32P‐labeled oligomer, a single TH mRNA of 1.9 kb was detected in adrenal gland and brain stem but not in liver and cerebral cortex. Using this TH‐specific oligomer, TH mRNAs were localized to the chromaffin cells in the adrenal medulla and to catecholaminergic neurons in locus coeruleus and substantia nigra by in situ hybridization histochemistry. After reserpine administration, the intensity of hybridization signal was increased to threefold that of normal in sections of adrenal medulla and twofold that of normal in locus ceruleus. No difference in hybridization signal intensity was observed in the substantia nigra of normal and reserpine‐treated animals. Use of this specific TH probe in in situ hybridization procedures represents a powerful approach to the study of regulation of TH gene expression at the cellula

ISSN:0360-4012    

DOI:10.1002/jnr.490170103

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1987

数据来源: WILEY

摘要:

AbstractA neuron‐survival assay with dissociated ciliary ganglion neurons was used to examine the level of neurotrophic activity in organs of the rat and chicken. All tissue homogenates enhanced neuron survival at increasing protein concentrations, although 50% survival activity (1 trophic unit, TU, per ml) occurred at distinctly different levels in the different organs. Liver, spleen, T‐cells, and submandibular gland from the rat were very low in survival‐promoting activity (0.1–1.1 TU per mg of protein). Serum and lung were slightly richer (2.4–2.8 mg). Heart, brain, and skeletal muscle stimulated survival well (6.2–13 TU/mg). Unexpectedly, the highest activities were found in the rat kidney (44 TU/mg). The activity in adult chicken organs was less varied (1.6–9.1 TU/mg). Higher trophic activities were found in the chicken embryo, particularly at day 18 of development (20–30 TU/mg). The up to 100‐fold difference in trophic level between organs should make it feasible to use subtractive hybridization, differential screening, and transient expression in eukaryotic cells for molecular cloning of the ciliary neuro

ISSN:0360-4012    

DOI:10.1002/jnr.490170104

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1987

数据来源: WILEY

摘要:

AbstractConsiderable controversy surrounds the question of whether or not nerve growth factor (NGF) or a related nerve growth‐promoting factor is present in serum. Recently, supporting its role as a local neuronotrophic factor, the presence of NGF in glial cells and its production in target tissues of NGF‐responsive neurons were demonstrated [Rush:Nature312:364–367, 1984; Heumann, Korsching, Scott, Thoenen:EMBOJ3:3183–3189, 1984; Shelton and Reichardt:Proc Natl Acad Sci USA81:7952–7955, 1984]. At the same time, the concept that NGF may play a role as a humoral factor has been questioned, since careful analyses of serum with specific and sensitive radioimmunoassays [Suda, Barde, Thoenen:Proc Natl Acad Sci USA75:4042–4046, 1978; Korsching and Thoenen;Proc Natl Acad Sci USA80:3513–3516, 1983; Furukawa, Kamo, Furukawa, Akazawa, Satoyoshi, Itoh, Hayashi:J Neurochem40:734–744, 1983] as well as bioassays [Skaper and Varon:Exp Neurol76:655–665, 1982] have not confirmed earlier reports [Levi‐Montacini and Booker;Proc Natl Acad Sci USA46:373–391, 1960; Banks, Banthorpe, Charlwood, Pearce, Vernon:Nature246:503–504, 1973; Hendry:Biochem J128:1265–1272, 1972] on NGF's representation in serum.In this study serum from mouse, rat, and man was analyzed with an in vitro bioassay system which employs sensory neurons from chicken embyro dorsal root ganglia and which allows the measurement of NGF concentrations as low as 0.8 pM. It was found that sera from all these species contained neuronotrophic activity (S‐NGF). The target cell spectrum as well as characteristic parameters of the neuronal growth response of S‐NGF and of NGF were identical. S‐NGF of mouse serum was completely inhibitable by polyclonal and monoclonal antibodies to mouse submandibular gland β NGF. On polyacrylamide isoelectric focussing gels mouse and human S‐NGF could be recovered from the same position as NGF as well as from the region where α2‐macroglobulin and serum albumin focused.In newborn and adult male and female mice basal S‐NGF levels were equivalent to 10–50 pM NGF. A. fraction of the serum samples of male mice showed elevated S‐NGF levels. The incidence of high S‐NGF levels was more frequent in NMRI and C57BL/6 males than in BALB/c males. Following sialectomy of male mice only basal S‐NGF levels were observed up to 5 weeks after the operation. This indicates that although the submandibular gland may contribute to S‐NGF levels in serum under certain conditions that appeared to be stre

ISSN:0360-4012    

DOI:10.1002/jnr.490170105

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1987

数据来源: WILEY

摘要:

AbstractWe have identified a new subline of PC12 pheochromocytoma cells (PC12D cells) in which neurites are extended within 24 hr in response to cAMP‐enhancing reagents as well as in response to nerve growth factor (NGF), but not in response to epidermal growth factor or phorbol diester. Anti‐NGF antiserum did not affect forskolin (FRK)‐induced neuritic recruitment. FRK‐induced neurites exhibited growth cones and contained secretion granules and many parallel arrays of microtubules as was the case with NGF‐induced neurites. FRK, but not NGF, increased the levels of intracellular cAMP and activated adenylate cyclase in the membrane fraction. Both NGF and FRK enhanced the activities of tyrosine hydroxylase (TH), acetylcholinesterase (AchE), and ornithine decarboxylase (ODC), but not the levels of neuron‐specific enolase. Enhanced levels of intracellular cAMP mimicked the effects of NGF on neuritic growth, TH, AchE, and ODC activities inPC12D cells, even though NGF does not act through elevation of lev

ISSN:0360-4012    

DOI:10.1002/jnr.490170106

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1987

数据来源: WILEY

摘要:

AbstractPrevious biochemical findings suggest that exogenous gangliosides enhance cholinergic sprouting in the hippocampus after partial lesions of the septohippocampal pathway. To assess whether GM1 ganglioside accelerates the onset of this sprouting after complete lesions, we measured cholinergic enzymes and Na, K‐ATPase activity in the hippocampus of rats with unilateral fimbria‐fornix transection. At 14 and 18 days postlesion, histochemical staining showed that acetylcholinesterase (AChE) was almost completely eliminated in the hippocampus ipsilateral to the transection in untreated and GM1‐treated rats. Biochemical assays confirmed that GM1 treaments did not increase AChE activity in the denervated hippocampus. Rather, there were significant reductions of AChE and choline acetyltransferase activities in the ipsilateral hippocampus relative to the contralateral value (P<.001); and the reductions were greater in GMI‐treated rats than in untreated controls (P<.001). Na, K‐ATPase activity in the ipsilateral hippocampus increased by 10.1% in GM1‐treated rats, whereas it decreased by 21.7% in untreated controls (P<.05). Since Na, K‐ATPase is enriched in synaptic membranes, the increased activity of this enzyme may indicate that GM1 treatments stabilize surviving synaptic membranes and/or accelerate the onset of sprouting in the denervated hippocampus. The reductions in cholinergic enyzymes, however, imply that the sprouting pathway must be n

ISSN:0360-4012    

DOI:10.1002/jnr.490170107

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1987

数据来源: WILEY

摘要:

AbstractTransferrin is the second most abundant plasma protein and functions to transport iron. It is an essential constituent in culture media for virtually all cells. In a recent study, we reported that transferrin (Tf) is specifically located in oligodendrocytes in the rat nervous system. This investigation examines immunohistochemically the development of Tf in the cerebral cortex, corpus striatum, and spinal cord. Tf is first seen in oligodendrocytes in the spinal cord white matter at 5 days of age. The immunoreactivity is confined to the white matter in the periphery of the spinal cord between 5 and 8 days of age. By 10–12 days of age, the number of immunoreactive oligodendrocytes in the spinal cord white matter increases considerably, corresponding to the onset of myelination. Tf‐positive oligodendrocytes are first found in the gray matter at 15 days of age. By 30 days of age, the number and distribution of Tf‐positive oligodendrocytes in both the brain and spinal cord have reached the adult pattern. The results of this study demonstrate a spatial and temporal association between Tf development and myelinogenesis. This suggests that part of the process of differentiation of oligodendrocytes includes the accumulation of Tf, perhaps in order to support the metabolic demands associated with the production and maintenance of m

ISSN:0360-4012    

DOI:10.1002/jnr.490170108

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1987

数据来源: WILEY

摘要:

AbstractAntibodies specific for the surface of oligodendrocytes were prepared by incubating living cultures of pure oligodendrocytes with a crude anti‐oligodendrocyte antiserum. These specific antibodies, when used in the technique of immunoelectroblotting, led to the characterization of at least two major plasma membrane proteins of 43 kilodaltons (kDa) and 53 kDa, respectively, as accessible at the external surface of the oligodendrocytes. The 53‐kDa protein was also found in oligodendrocyte‐conditioned medium in significant amounts. Additional oligodendrcyte surface proteins were also detected in the Wolfgram protein fra

ISSN:0360-4012    

DOI:10.1002/jnr.490170109

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1987

数据来源: WILEY

摘要:

AbstractLong‐chain acyl‐CoA synthetase (EC 6.2.1.3), an enzyme(s) that activates fatty acids prior to incorporation into phospholipids and other substances, has been detected in highly purified myelin from rat brain stem. The high levels relative to microsomes (11% and 15% for oleate and arachidonate, respectively) tended to preclude contamination by the latter membrane as the source of activity. Additional evidence came from sequential purification and mixing experiments. Km values were not appreciably different for the two substrates with the two membranes, but Vmaxvalues were approximately 2–4‐fold greater for arachidonate in both membranes. Triton X‐100 increased activity somewhat in myelin but not in microsomes; with arachidonate as substrate it reduced activity in the latter. Heat inactivation studies and pH profiles suggested the presence of two different enzymes, as previously shown for othe

ISSN:0360-4012    

DOI:10.1002/jnr.490170110

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1987

数据来源: WILEY

摘要:

AbstractOur laboratory has reported previously the characteristics of specific AVP binding to rat hippocampal synaptic membranes (SPM) in the presence of Ni2+[Costantini MG, Pearlmutter AF:J Biol Chem259:11739–11745, 1984]. We extended our investigation to determine the effects of Ni2+, (AVP), and AVP analogs on SPM protein phosphorylation. Ni2+(5 mM) caused a dramatic reduction in phosphorylation of most SPM phosphoproteins. The most prominent protein which is phosphorylated in SPM has a molecular weight of 48 kilodaltons (KDa) and has been named B50 or F1; this protein shows altered phosphorylation in vitro in response to long‐term potentiation in vivo as well as changes induced by exposure of SPM to ACTH (1–24), dopamine, and somatostatin. AVP and related peptides reduced phosphorylation of this presynaptic phosphoprotein in the following order of potency: AVP = oxytocin>DG‐AVP>dDAVP>d(CH2)5Tyr(Me) AVP = [pGlu4, Cyt6]AVP‐(4–9). Except for the pressor antagonist d(CH2)5Tyr(Me)AVP, this corresponds to their relative efficacy in displacing3H‐AVP from high‐affinity specific binding sites on rat hippocampal synaptic membranes. Ni2+did not alter the degree of inhibition caused by the peptides. When SPM were treated with AVP after the attainment of maximum32P incorporation, AVP inhibited dephosphorylation over a 30‐min period. Our results show that AVP can alter both phosphorylation and dephosphorylation of hippocampal SPM phosphoproteins in vitro; the direction of these effects depends upon experimental conditions. Since B50/F1 is known to be a substrate for protein kinase C, AVP may act by inhibition of protein kinase C activity, either direc

ISSN:0360-4012    

DOI:10.1002/jnr.490170111

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1987

数据来源: WILEY