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PubMedDate not supplied

Targeting of proteins to the Golgi apparatus.

The proteins that reside in the Golgi carry out functions associated with post-translational modifications, including glycosylation and proteolytic processing, membrane transport, recycling of endoplasmic reticulum proteins and maintenance of the structural organisation of the organelle itself. The latter includes Golgi stacking, interconnections between stacks and the microtubule-dependent positioning of the organelle within the cell. There are a number of distinct groups of Golgi membrane proteins, including glycosyltransferases, recycling trans-Golgi network (TGN) proteins, peripheral membrane proteins and receptors. Considerable effort has been directed at understanding the basis of the localisation of Golgi glycosyltransferases and recycling TGN proteins; in both cases there is increasing evidence that multiple signals may be involved in their specific localisation. A number of models for the Golgi retention of glycosyltransferases have been proposed including oligomerisation, lipid-mediated sorting and intra-Golgi retrograde transport. More information is required to determine the contribution of each of these potential mechanisms in the targeting of different glycosyltransferases. Future work is also likely to focus on the relationship between the localisation of resident Golgi proteins and the maintenance of Golgi structure.

Animals↗
PubMed2005

Kinases regulating Golgi apparatus structure and function.

Protein kinases control Golgi function in both mitotic and interphase cells. In mitosis, phosphorylation of structural proteins by Cdk1 (cyclin-dependent kinase 1)-cyclin B, Polo-like and mitogen-activated protein kinases underlie changes in Golgi reorganization during cell division. While in interphase, signalling pathways that are associated with the Golgi control secretory function through a variety of mechanisms. Some of these, notably those involving protein kinase D and Ste20 family kinases, are also relevant for the establishment and maintenance of cell polarization and migration.

Animals↗
PubMed1978

Biochemical activity and morphology of the Golgi apparatus in alloxan diabetic rats.

In Golgi-enriched membrane fraction isolated from alloxan diabetic rat liver, the protein content is lower but the protein composition is similar to normal. The specific activity of galactosyl transferase in this membrane fraction is higher than normal, but the total activity of the enzyme in the whole liver is normal. Great dispersion is found among the individual values. Differences in the specific activities of some other marker enzymes were also found in the Golgi-enriched membrane fraction. The morphology of the Golgi complex examined in either thin sections of Golgi-enriched fraction or ultra-thin sections of livers appears normal. A slight reduction of the rough endoplasmic reticulum is observed. The results obtained are discussed in comparison with those obtained for streptozotocin diabetic rat liver.

Animals↗
PubMed1992

Segregation of secretory material in all elements of the Golgi apparatus in principal epithelial cells of the rat seminal vesicle.

At the apex of the epithelial principal cells of the seminal vesicle, there appears to be two types of mature secretory granules, i.e., large and small. Both types of secretory granules showed an eccentric electron-dense spherical body with one pole attached to the delimiting membrane. The remainder of the large granule surrounding the eccentric body showed a granulofilamentous texture, whereas that of the small granule was electron lucent. The formation of these two types of granules was traced back to the various elements of the Golgi stacks. In the case of the large granules, the earliest stage of segregation of the precursor of the eccentric dense body was observed in distensions of the cis-element. Within distensions of all subjacent saccules, the dense bodies continued to be present but progressively increased in size while remaining attached to the saccular membrane. Following separation from the trans-face of the stack, the large prosecretory granules continued to increase in size by fusing with each other. The very large prosecretory granules, as they migrated toward the cell apex to become mature secretory granules, reduced in size prior to exocytosis. The small granules formed exclusively on the trans-aspect of the Golgi stacks and did not appear to fuse with each other. Observations on the formation of the large prosecretory granules within the Golgi apparatus and of the eccentric body in particular, which may be taken as a marker of the saccular membrane, were suggestive of a cis-trans migration and renewal of Golgi saccules.

Animals↗
PubMed1984

Asymmetric acetylcholinesterase is assembled in the Golgi apparatus.

The synthesis, assembly, and processing of the multiple molecular forms of acetylcholinesterase (AcChoEase; acetylcholine acetylhydrolase, EC 3.1.1.7) in quail muscle cultures was studied by using lectins to distinguish enzyme molecules residing in different subcellular compartments. Special emphasis was given to the assembly of asymmetric AcChoEase molecules because these appear to be the predominant, if not unique, forms of AcChoEase at the vertebrate neuromuscular junction. All cell surface and secreted AcChoEase forms bind to immobilized wheat germ agglutinin, ricin, and concanavalin A, indicating that they have complex oligosaccharides. After treatment of muscle cells with a membrane-permeable irreversible AcChoEase inhibitor, there is a rapid reappearance of the globular monomeric, dimeric, and tetrameric AcChoEase forms. However, the collagen-tailed asymmetric form does not appear until about 90 min after treatment. Analysis of the AcChoEase oligosaccharides with lectins indicates maturation to complex forms over a 90-min period. A large fraction of the intracellular globular AcChoEase molecules bind only to concanavalin A, indicating that they are assembled in the rough endoplasmic reticulum. In contrast, all intracellular asymmetric AcChoEase binds to wheat germ agglutinin, and a significant fraction binds to ricin, indicating that this unique AcChoEase form is assembled from subunits that have previously acquired complex sugars. I conclude that assembly of asymmetric AcChoEase, hence acquisition of information specifying basal lamina localization, occurs in the Golgi apparatus.

Acetylcholinesterase↗
PubMed2004

VAMP-associated protein-A regulates partitioning of oxysterol-binding protein-related protein-9 between the endoplasmic reticulum and Golgi apparatus.

We recently showed that oxysterol-binding protein (OSBP), one of twelve related PH domain containing proteins with lipid and sterol binding activity, interacts with VAMP-associated protein (VAP)-A on the endoplasmic reticulum (ER). In addition to OSBP, seven OSBP-related proteins (ORPs) bind VAP-A via a conserved E-F/Y-F/Y-DA 'FFAT' motif. We focused on this interaction for ORP9, which is expressed as a full-length (ORP9L) or truncated version missing the PH domain (ORP9S). Mutation analysis showed that the interaction required the ORP9 FFAT motif and the N-terminal conserved domain of VAP. Endogenous ORP9L displayed Golgi localization, which was partially mediated by the PH domain based on limited localization of OPR9-PH-GFP with the Golgi apparatus. When inducibly overexpressed, ORP9S and ORP9L colocalized with VAP-A and caused vacuolation of the ER as well as retention of the ER-Golgi intermediate compartment marker ERGIC-53/p58 in the ER. ORP9L mutated in the VAP-A binding domain (ORP9L-FY-->AA) did not localize to the ER but appeared with giantin and Sec31 on large vesicular structures, suggesting the presence of a hybrid Golgi-COPII compartment. Normal Golgi localization was also observed for ORP9L-FY-->AA. Results show that VAP binding and PH domains target ORP9 to the ER and a Golgi-COPII compartment, respectively, and that ORP9L overexpression in these compartments severely perturbed their organization.

Alternative Splicing↗
PubMed1985

The reorientation of the Golgi apparatus and the microtubule-organizing center in the cytotoxic effector cell is a prerequisite in the lysis of bound target cells.

This investigation is concerned with the detailed mechanisms of cytotoxicity, and in particular, with early cell surface and intracellular events that occur upon the binding of a cytotoxic effector cell to its susceptible target. In earlier studies, we have shown by immunofluorescence microscopy that when cloned natural killer (NK) and cytolytic T lymphocyte (CTL) cells bind to susceptible target cells, a rapid and coordinate reorientation of the perinuclear Golgi apparatus and the microtubule-organizing center (MTOC) occurs inside the effector cell so that the two organelles face the bound target. It was proposed that the purpose served by this reorientation is to direct Golgi-derived secretory vesicles, containing one or more cytotoxic components, to the area of target cell binding. In order to establish more firmly that this reorientation of the two organelles is an essential early event in cytotoxicity, we have performed three different types of experiments. 1) Upon binding cloned effector cells to susceptible targets in the presence of Mg+2 but absence of Ca+2, conditions in which no killing occurs, we found that no reorientation of the MTOC in the effector cell is induced; however, the addition of CA+2 to these cell couples results in a rapid MTOC reorientation. 2) With a lysis-defective subclone derived from a cytolytic NK clone, binding to target cells did not induce an MTOC reorientation in the defective killer cell. 3) In multitarget conjugates formed with single CTL, the MTOC in the CTL was oriented to face that one target cell which was in the process of lysis at the time. These results, together with our earlier findings, strongly indicate that a Golgi/MTOC reorientation inside the target-bound effector cell is a pre-requisite for the effective lysis of the target. They also reveal the existence, previously unrecognized, of a specific signaling mechanism from the viable target cell to the effector cell, which must be involved in the triggering of this Golgi/MTOC reorientation. These conclusions are consistent with the proposal that a polar cytotoxic secretory mechanism is responsible for target cell lysis.

Animals↗
PubMed1981

An increase in smooth endoplasmic reticulum and a decrease in Golgi apparatus occur with ionic conditions that block initiation of fast axonal transport.

The ultrastructure of bullfrog spinal ganglia was analyzed after incubation in media containing concentrations of calcium and cobalt known to inhibit export of proteins from the soma to the axon. Although most somal organelles were morphologically unchanged by the various incubation media, striking changes were seen in the smooth endoplasmic reticulum (SER) and the Golgi apparatus (GA). In order of effect, calcium-free medium (CFM), normal medium supplemented with cobalt (NM--Co), and CFM supplemented with cobalt (CFM--Co) produced increasing amounts of SER coupled with decreasing densities of GA stacks. In the extreme case, CFM--Co incubation resulted in a nearly 10-fold increase in SER volume as well as in a virtually complete depletion of GA stacks. Axons originating within the ganglion were also examined and showed little change after the various incubations. The rank order of the altered incubation media in producing morphological changes was the same as the relative effectiveness of the media in depressing the fast axonal transport of [3H]protein within the dorsal root ganglion neurons. The morphological and biochemical results are discussed with respect to establishing the localization of the calcium-dependent step(s) that has been proposed to occur in the neuronal soma during the initiation of axonal transport.

Animals↗
PubMed1981

Passage of an integral membrane protein, the vesicular stomatitis virus glycoprotein, through the Golgi apparatus en route to the plasma membrane.

The intracellular pathway of biogenesis of the vesicular stomatitis virus transmembrane glycoprotein was investigated in situ by using indirect immunofluorescence of whole infected Chinese hamster ovary cells and immunoelectron microscopy of ultrathin frozen sections of infected cells. Transport of the glycoprotein was synchronized by using the temperature-sensitive virus mutant Orsay-45 and a temperature shift-down protocol. Sequential appearance of the glycoprotein in the rough endoplasmic reticulum, Golgi apparatus, and plasmalemma was demonstrated. The potential of this system for further studies is discussed.

Animals↗
PubMed1996

Mammalian vesicle trafficking proteins of the endoplasmic reticulum and Golgi apparatus.

Vesicle traffic propagates and maintains distinct subcellular compartments and routes secretory products from their site of synthesis to their final destinations. As a basis for the specificity of vesicular transport reactions, each step in the secretory pathway appears to be handled by a distinct set of evolutionarily conserved proteins. Mammalian proteins responsible for vesicle trafficking at early steps in the secretory pathway are not well understood. In this report, we describe rat sec22 (rsec22) and rat bet1 (rbet1), mammalian sequence homologs of yeast proteins identified as mediators of endoplasmic reticulum-to-Golgi protein transport. rsec22 and rbet1 were expressed widely in mammalian tissues, as anticipated for proteins involved in fundamental membrane trafficking reactions. Recombinant rsec22 and rbet1 proteins behaved as integral membrane components of 28 and 18 kDa, respectively, consistent with their primary structures, which contain a predicted transmembrane domain at or near the carboxyl terminus. Recombinant rsec22 and rbet1 had distinct subcellular localizations, with rsec22 residing on endoplasmic reticulum membranes and rbet1 found on Golgi membranes. Studies with brefeldin A and nocodazole indicated that rbet1 function might involve interaction with or retention in the intermediate compartment. The distinct localizations of rsec22 and rbet1 may reflect their participation in opposite directions of membrane flow between the endoplasmic reticulum and Golgi apparatus.

Amino Acid Sequence↗
PubMed2003

The ARF-like GTPases Arl1p and Arl3p act in a pathway that interacts with vesicle-tethering factors at the Golgi apparatus.

The ARLs are a diverse family of GTPases that are related to ADP-ribosylation factors (ARFs), but whose function is poorly understood. There are at least ten ARLs in humans, two of which have homologs in the yeast Saccharomyces cerevisiae (ARL1/Arl1p and ARFRP1/Arl3p). The function of ARFRP1 is unknown, but mammalian ARL1 has recently been found to interact with a number of effectors including the GRIP domain that is present in a family of Golgi-localized long coiled-coil proteins. We find that in yeast, the intracellular targeting of Imh1p, the only yeast GRIP domain protein, is dependent on both Arl1p and Arl3p, but not on the ARF proteins. A recombinant form of the Imh1p GRIP domain binds to Arl1p in a GTP-dependent manner, but not to Arl3p. Yeast also contain a relative of SCOCO, a protein proposed to bind human ARL1, but this yeast protein, Slo1p, appears to bind Arl3p rather than Arl1p in vitro. However, Imh1p is not the sole effector of Arl1p since affinity chromatography of cytosol with immobilized Arl1p:GTP revealed an interaction with the GARP/VFT complex that is thought to act in the tethering of vesicles to the Golgi apparatus. Finally, we find that Arl3p is required in vivo for the targeting of Arl1p, explaining its requirement for the normal distribution of Imh1p.

ADP-Ribosylation Factors↗
PubMed1992

Prolactin granulogenesis is associated with increased secretogranin expression and aggregation in the Golgi apparatus of GH4C1 cells.

The GH4C1 pituitary tumor cell line (GH cells) serves as a model system to study the role of the granins in the packaging of PRL into secretory granules. The number of secretory granules containing PRL and two members of the granin family, chromogranin-B (CgB) and secretogranin-II (SgII), can be hormonally manipulated. In the present study we have investigated whether 1) granulogenesis in GH cells is preceded by condensation of the granins and PRL in the Golgi; 2) granulogenesis is preceded by an increase in granin expression in GH cells; and 3) PRL and the granins aggregate in vitro under high calcium, low pH conditions. GH cells were treated for up to 3 days with 17 beta-estradiol (1 nM), insulin (300 nM), and epidermal growth factor (10 nM) and were fixed in 4% paraformaldehyde for immunocytochemistry or harvested for RNA isolation and Northern blot analysis. After 1 day of hormone treatment, there was a significant increase in staining for PRL and the granins in the Golgi apparatus, which was identified using an antibody to MG-160. After 3 days of hormone treatment, PRL and granin staining was also found in a perinuclear region that was not stained with anti-MG-160 antibody, most likely representing secretory granules. An increase in PRL and granin expression contributed to increased Golgi staining, as the steady state levels of CgB, SgII, and PRL mRNA increased 186 +/- 14%, 203 +/- 7%, and 337 +/- 5% above control levels, respectively, within 6 h after hormone treatment. An in vitro aggregation system was used to determine whether PRL and the granins coprecipitate under high calcium, low pH conditions, which are thought to be characteristic of the trans-Golgi and secretory granules. Aggregation of the granins CgB and SgII was negligible during overnight dialysis against a buffer containing 150 mM NaCl and 10 mM 2[N-morpholino]ethanesulfonic acid-NaOH (pH 5.5) in the absence of calcium. There was significant aggregation of PRL under these conditions. When dialysis was performed in the presence of 10 mM CaCl2, PRL, CgB, and SgII coaggregated. This study indicates that increased expression and aggregation of the granins is associated with PRL granulogenesis in hormone-treated GH cells. However, the role of the granins may not be obligatory, as some cells can store PRL in the absence of detectable levels of CgB and SgII, and PRL has the capacity to self-aggregate.

Animals↗
PubMed2001

Neurosecretory granule formation in ligated axons: additional arguments for a local differentiation from a Golgi apparatus extension.

The sorting domain for the different types of granules and small synaptic vesicles in neurosecretion is still largely a matter of debate. Some authors state that an exocytotic process has to precede granule formation. In previous studies, we favoured the idea that neurosecretory packages in terminals are assembled from axonal reticulum membranes simply by differentiation at the axon ending, the axonal reticulum being an extension of the Golgi apparatus. By ligating bovine splenic nerve, a de novo differentiation can be induced. After ligation, granules and granulo-tubular complexes appear. They were immunoreactive for SV2, VMAT2 and synaptobrevin II, which are all known to be highly enriched in large dense granules. Previously the granulo-tubular structures have already been recognized as precursor stadia of neurosecretory granules. It is concluded that at a de novo differentiation, a sorting out and aggregation is taking place of molecules typical for large dense granules. The small dense granules and tubules can be considered unripe, precursor forms of the large dense granules. All this occurs in the absence of signs of exocytosis. The present findings corroborate the view that granule formation occurs via local differentiation at an axon ending.

Animals↗
PubMed1992

Functional compartmentation of the Golgi apparatus of plant cells : immunocytochemical analysis of high-pressure frozen- and freeze-substituted sycamore maple suspension culture cells.

The Golgi apparatus of plant cells is engaged in both the processing of glycoproteins and the synthesis of complex polysaccharides. To investigate the compartmentalization of these functions within individual Golgi stacks, we have analyzed the ultrastructure and the immunolabeling patterns of high-pressure frozen and freeze-substituted suspension-cultured sycamore maple (Acer pseudoplatanus L.) cells. As a result of the improved structural preservation, three morphological types of Golgi cisternae, designated cis, medial, and trans, as well as the trans Golgi network, could be identified. The number of cis cisternae per Golgi stack was found to be fairly constant at approximately 1, whereas the number of medial and trans cisternae per stack was variable and accounted for the varying number of cisternae (3-10) among the many Golgi stacks examined. By using a battery of seven antibodies whose specific sugar epitopes on secreted polysaccharides and glycoproteins are known, we have been able to determine in which types of cisternae specific sugars are added to N-linked glycans, and to xyloglucan and polygalacturonic acid/rhamnogalacturonan-I, two complex polysaccharides. The findings are as follows. The beta-1,4-linked d-glucosyl backbone of xyloglucan is synthesized in trans cisternae, and the terminal fucosyl residues on the trisaccharide side chains of xyloglucan are partly added in the trans cisternae, and partly in the trans Golgi network. In contrast, the polygalacturonic/rhamnogalacturonan-I backbone is assembled in cis and medial cisternae, methylesterification of the carboxyl groups of the galacturonic acid residues in the polygalacturonic acid domains occurs mostly in medial cisternae, and arabinose-containing side chains of the polygalacturonic acid domains are added to the nascent polygalacturonic acid/rhamnogalacturonan-I molecules in the trans cisternae. Double labeling experiments demonstrate that xyloglucan and polygalacturonic acid/rhamnogalacturonan-I can be synthesized concomitantly within the same Golgi stack. Finally, we show that the xylosyl residue-linked beta-1,2 to the beta-linked mannose of the core of N-linked glycans is added in medial cisternae. Taken together, our results indicate that in sycamore maple suspension-cultured cells, different types of Golgi cisternae contain different sets of glycosyl transferases, that the functional organization of the biosynthetic pathways of complex polysaccharides is consistent with these molecules being processed in a cis to trans direction like the N-linked glycans, and that the complex polysaccharide xyloglucan is assembled exclusively in trans Golgi cisternae and the trans Golgi network.

Journal Article↗
PubMed1990

Effects of inositol 1,4,5-trisphosphate on calcium release from the endoplasmic reticulum and Golgi apparatus in mouse mammary epithelial cells: a comparison during pregnancy and lactation.

It has been established that inositol 1,4,5-trisphosphate(IP3) is responsible for the mobilization of calcium(Ca2+) from intracellular locations in a wide variety of tissues, and that this response triggers the stimulation of several hormones and neurotransmitters. However, these phenomena have yet to be examined in the mammary epithelium. Ca2+ uptake from the medium into the endoplasmic reticulum(ER) and Golgi apparatus in vitro in both pregnant and lactating mouse mammary epithelial cells was studied and a strong Ca2+ release from these organelles into the medium with the use of IP3 was shown. The Ca2+ uptake and its release due to IP3 was also usually greater during pregnancy than lactation.

Animals↗
PubMed1999

The genes for the Golgi apparatus N-acetylglucosaminyltransferase and the UDP-N-acetylglucosamine transporter are contiguous in Kluyveromyces lactis.

The mannan chains of Kluyveromyces lactis mannoproteins are similar to those of Saccharomyces cerevisiae except that they lack mannose phosphate and have terminal alpha(1-->2)-linked N-acetylglucosamine. Previously, Smith et al. (Smith, W. L. Nakajima, T., and Ballou, C. E. (1975) J. Biol. Chem. 250, 3426-3435) characterized two mutants, mnn2-1 and mnn2-2, which lacked terminal N-acetylglucosamine in their mannoproteins. The former mutant lacks the Golgi N-acetylglucosaminyltransferase activity, whereas the latter one was recently found to be deficient in the Golgi UDP-GlcNAc transporter activity. Analysis of extensive crossings between the two mutants led Ballou and co-workers (reference cited above) to conclude that these genes were allelic or tightly linked. We have now cloned the gene encoding the K. lactis Golgi membrane N-acetylglucosaminyltransferase by complementation of the mnn2-1 mutation and named it GNT1. The mnn2-1 mutant was transformed with a 9.5-kilobase (kb) genomic fragment previously shown to contain the gene encoding the UDP-GlcNAc transporter; transformants were isolated, and phenotypic correction was monitored after cell surface labeling with fluorescein isothiocyanate-conjugated Griffonia simplicifolia II lectin, which binds terminal N-acetylglucosamine, and a fluorescence-activated cell sorter. The above 9.5-kb DNA fragment restored the wild-type lectin binding phenotype of the transferase mutant; further subcloning of this fragment yielded a smaller one containing an opening reading frame of 1,383 bases encoding a protein of 460 amino acids with an estimated molecular mass of 53 kDa, which also restored the wild-type phenotype. Transformants had also regained the ability to transfer N-acetylglucosamine to 3-0-alpha-D-mannopyranosyl-D-mannopyranoside. The gene encoding the above transferase was found to be approximately 1 kb upstream from the previously characterized MNN2 gene encoding the UDP-GlcNAc Golgi transporter. Each gene can be transcribed independently by their own promoter. To our knowledge this is the first demonstration of two Golgi apparatus functionally related genes being contiguous in a genome.

Amino Acid Sequence↗
PubMed1978

Histochemical studies on the morphology of the Golgi apparatus and its relation to catecholamine biosynthesis in the locus coeruleus of Rhesus and crab-eating monkeys.

Detailed histochemical studies have been conducted on the distribution of thiamine pyrophosphatase (TPPase), L-gulonolactone oxidase (GLO), and NAD-linked xylitol dehydrogenase (XDH) in every component of the Locus coeruleus (LC) of healthy adult male Rhesus and crab-eating monkeys in order to clearify the morphology of the Golgi apparatus (GA) and its relation to biosynthesis of catechol-amines in this special nucleus of the primate (NA nucleus A 6 as defined in the Rhesus monkey by German and Bowden [1975]). Medium-sized neurons of both species of monkeys, which are considered to play an important role in the LC, were classified into 5 groups on the basis of morphological patterns of the GA. Many neurons of both species of monkeys were positive for the XDH test while some neurons of the crab-eating monkey as well as a few neurons of the Rhesus monkey were positive for the GLO reaction. The LC of both species of monkeys must be composed of metabolically one kind of identical medium-sized parasympathetic neurons whose GA may continously undergo 5 distinct phasic changes depending on the functional state of that cell. However, the GA changes its shape much more significantly even within each group of the 5 in the crab-eating monkey than in the Rhesus monkey. The GA Type IV may correspond to the catabolic phase of the GA during which biosynthesis of both catecholamines and vitamin C should be going on. Production of vitamin C may greatly help biosynthesis of catecholamines in LC. The difference in species is evident between the 2 kinds of monkeys studied in regard to the degree of their ability to synthesize these substances. The degree of the ability to synthesize vitamin C parallels the density distribution of Type IV neurons in LC whose GA often develops much more greatly in the crab-eating monkey than in the Rhesus monkey.

Alcohol Oxidoreductases↗
PubMed1982

Histochemical studies on the relationship between the morphology of the Golgi apparatus and G6PD activity in the locus coeruleus and dorsal vagal nucleus of the rat (application of karyometry).

Histochemical studies on the distribution of TPPase and G6PD in the neurons of locus coeruleus (LC) and dorsal vagal nucleus (DVN) of rats have been conducted by using the TPPase method, the G6PD method, karyometry, and statistics under normal conditions. 1. Neurons of the LC and DVN may undergo phasic changes of the GOLGI apparatus (GA) under normal condition. 2. No significant difference was found between neurons of the LC and DVN in regard to the GA morphology, but in general the latter revealed more complicated and developed GA than in the former. 3. Surprisingly, the G6PD activity of LC neurons was very weak. This is in agreement with the previous report by IIJIMA and IMAI (1975), and in disagreement with FRIEDE (1966). 4. An intimate parallel relationship was found between the GA morphology and G6PD activity in the DVN. The findings support the vigorous synthesizing activity found in the previous study of the rat supraoptic nucleus (IIJIMA 1979). In contrast to the DVN, such a parallel relationship between the Ga shape and G6PD activity was absent in the LC. Both findings strongly suggest that the role of the GA may be functionally different in the LC and DVN.

Animals↗