PubMed Health⌕ Search

Biomedical subjects

S Hein

Publications and source records attributed to S Hein.

At least 19 recordsLinked to original sources
PubMed1998

Partial sequencing of Reissner's fiber glycoprotein I (RF-Gly I).

The bulk of the secretion of the subcommissural organ is formed by glycoproteins that appear to be derived from two precursor forms of 540 and 320 kDa. Upon release into the ventricle, these glycoproteins aggregate to form Reissner's fiber. We report the isolation of three cDNA clones from a cDNA library prepared from bovine subcommissural organ RNA, by using an anti-Reissner's fiber serum for immunoscreening. Inserts of 0.7, 1.2, and 2.5 kb were amplified by the polymerase chain reaction, subcloned into pUC18 vector, and sequenced. Although restriction mapping of the three inserts initially suggested that all of them were derived from the same mRNA, sequence analysis showed that a short non-homologous region was present in the 0.7-kb insert when compared with the 1. 2-kb and 2.5-kb inserts, suggesting that they corresponded to two different, although highly homologous, mRNAs. Northern analyses showed a single mRNA species of approximately 9.5 kb present in the subcommissural organ and missing in the choroid plexus, brain cortex, and liver. In situ hybridization confirmed that the expression of the RNA was restricted to cells of the bovine subcommissural organ. Polyclonal antibodies raised against a synthetic peptide, whose amino-acid sequence was deduced from the 2.5-kb cDNA, reacted specifically with the bovine and rat subcommissural organ-Reissner's fiber complex. In immunoblots of bovine subcommissural organ, this antibody revealed the precursor 540-kDa form and its putative processed form of 450 kDa. It is concluded that the cloned cDNA encodes for the major constitutive glycoprotein of Reissner's fiber, here designated as RF-Gly I. The sequenced region of RF-Gly I displays a high degree of homology with some regions of the von Willebrand factor and certain mucins; it also displays two motifs homologous with repeats present in proteins of the spondin family and other proteins. A core sequence of the RF-Gly I repeats suggests that this molecule displays protein-binding properties.

Amino Acid Sequence↗
PubMed1997

Biosynthesis of poly(4-hydroxybutyric acid) by recombinant strains of Escherichia coli.

The aim of this study was the production of the homopolyester poly(4-hydroxybutyric acid) (poly(4HB)) with recombinant strains of Escherichia coli. Wild-type strains and other widely used non-recombinant strains of E. coli are not able to produce polyhydroxyalkanoic acids (PHA) as storage compounds and cannot utilize 4-hydroxybutyric acid as sole carbon source. Accordingly, hybrid plasmids of pBluescript vectors were constructed which harbored the Alcaligenes eutrophus PHA synthase gene (phaC) and the Clostridium kluyveri orfZ putatively encoding a 4-hydroxybutyric acid-coenzyme A transferase. A 3.5-kb genomic SmaI/ApaI fragment from A. eutrophus, which comprises phaC, and a 1.8-kb genomic ApaI/EcoRI fragment from C kluyveri, which contained orfZ, were inserted into the SmaI and EcoRI sites of the vectors pKS- and pSK-, respectively. The two resulting plasmids pSKSE5.3 and pKSSE5.3 comprising phaC and orfZ colinear or antilinear to lacZ, respectively, were transformed into E. coli XL1-Blue. Recombinant strains synthesized the homopolyester poly(4HB), when the cells were cultivated in Luria-Bertani broth and if glucose and 4-hydroxybutyric acid were provided as carbon sources. If glucose was omitted, a copolyester of 3-hydroxybutyric acid and 4-hydroxybutyric acid was accumulated. The homopolyester poly(4HB) was also accumulated during cultivation of these strains in M9 mineral salts medium containing glucose plus 4-hydroxybutyric acid as carbon sources. Poly(4HB) could amount up to approximately 80% (w/w) of the cell dry matter if E. coli XL1-Blue harboring pKSSE5.3 was cultivated in M9 mineral salts medium and if the cultures were not sufficiently supplied with oxygen. 4HB was also incorporated into PHA if gamma-butyrolactone was used as carbon source. If levulinic acid, 4-hydroxyvaleric acid or gamma-valerolactone were used as carbon sources, only very low amounts of PHA were accumulated which did not contain 4-hydroxyalkanoic acids as constituents.

4-Butyrolactone↗
PubMed1997

Inhibition of carrageenan-induced spinal c-Fos activation by systemically administered c-fos antisense oligodeoxynucleotides may be facilitated by local opening of the blood-spinal cord barrier.

Proto-oncogenes of the fos and jun family are rapidly expressed in the central nervous system following various stimuli. Proto-oncogene encoded nuclear proteins such as c-Fos or c-Jun act as transcription factors that may link neuronal excitation to changes in target gene expression. However, the precise in vivo functions of proto-oncogenes in neuroplasticity are still poorly understood. In the present study the effect of systemically administered c-fos antisense oligodeoxynucleotides (ODNs) on c-Fos and dynorphin protein levels in rat L4 spinal cord has been investigated by immunohistochemistry during carrageenan-induced hindpaw inflammation. Continuous infusion of terminal-phosphorothioated c-fos antisense ODNs by subcutaneously implanted miniosmotic pumps for 3 days sequence-specifically suppressed c-Fos protein expression in dorsal horn neurons by about 50%, while the increase in c-Jun immunopositive nuclei was not affected. Digital image analysis revealed a concomitant decrease in spinal dynorphin immunoreactivity. Moreover, 48 hr after carrageenan injection into one hindpaw plasma protein extravasation was observed in numerous blood vessels in the ipsilateral dorsal horn using intravenously administered Evans Blue. Our results provide further evidence that c-Fos may contribute to the regulation of spinal dynorphin gene expression following noxious stimulation. The local increase in blood-spinal cord barrier permeability during sustained peripheral inflammation may permit penetration of hydrophilic antisense ODNs into the central nervous system.

Animals↗
PubMed1996

Alcaligenes eutrophus possesses a second pyruvate dehydrogenase (E1).

Two gene loci, which hybridized with pdhA, the structural gene of the E1 component of the Alcaligenes eutrophus pyruvate dehydrogenase complex [Hein, S. & Steinbüchel, A. (1994) J. Bacteriol. 176, 4394-4408], were identified on two nonrelated A. eutrophus chromosomal BamHI fragments by using a pdhA-specific DNA probe. These data indicated that A. eutrophus possesses, beside PdhA, two additional distinct pyruvate dehydrogenases (E1). A 6.8-kbp genomic BamHI fragment of A. eutrophus was cloned, and sequence analysis of a 3.896-kbp region revealed the structural gene pdhE (2.694 kbp) for a second pyruvate dehydrogenase (E1), which was not clustered with structural genes for other components of 2-oxo acid dehydrogenase complexes. The A. eutrophus pdhE gene product (898 amino acid residues) exhibited significant similarities to the E1 components of the pyruvate dehydrogenase complexes of A. eutrophus, Neisseria meningitidis, Escherichia coli and Azotobacter vinelandii, which are also composed of only one type of subunit. Heterologous expression of pdhE in the aceEF deletion mutant E. coli YYC202 was demonstrated by spectrometric detection of enzyme activities and by phenotypic complementation to acetate prototrophy. These complementation studies indicated that the E1 component of the A. eutrophus pyruvate dehydrogenase complex can be replaced by a functionally active pdhE gene product.

Alcaligenes↗
PubMed1996

Cloning and characterization of the Alcaligenes eutrophus 2-oxoglutarate dehydrogenase complex.

Nucleotide sequence analysis of a 3.3-kb genomic EcoRI fragment and of relevant subfragments of a genomic 13.2-kb SmaI fragment of Alcaligenes eutrophus, which were identified by using a dihydrolipoamide dehydrogenase-specific DNA probe, revealed the structural genes of the 2-oxoglutarate dehydrogenase complex in a 7.5-kb genomic region. The genes odhA (2850 bp), odhB (1248 bp), and odhL (1422 bp), encoding 2-oxoglutarate dehydrogenase (E1), dihydrolipoamide succinyltransferase (E2), and dihydrolipoamide dehydrogenase (E3), respectively, occur co-linearly in one gene cluster downstream of a putative -35/-10 promoter in the order odhA, odhB, and odhL. In comparison to other bacteria, the occurrence of genes for two E3 components for the pyruvate as well as for the 2-oxoglutarate dehydrogenase complexes is unique. Heterologous expression of the A. eutrophus odh genes in E. coli XL1-Blue and in the kgdA mutant Pseudomonas putida JS347 was demonstrated by the occurrence of protein bands in electropherograms, by spectrometric detection of enzyme activities, and by phenotypic complementation, respectively.

Alcaligenes↗
PubMed1996

Pathogenesis of dilated cardiomyopathy and heart failure: insights from cell morphology and biology.

The cause of dilated cardiomyopathy is not yet clear but the recent discovery of a chromosomal aberration as well as the presence of autoantibodies indicate a multicausal origin. Knowledge of pathogenetic mechanisms continues to evolve and includes decreased sarcoplasmic reticulum Ca2+ uptake, reduced beta-receptor density and decreased contractility, the presence of enlarged myocytes showing numerous degenerative alterations, and fibrosis. Defects in titin, a large sarcomeric protein, may be responsible for disturbances of sarcomerogenesis in dilated cardiomyopathy. New animal models are promising but significant progress will also be made using cell culture systems like adult cardiac myocytes.

Animals↗
PubMed1995

Selenium in serum and whole blood in patients with surgical interventions.

Selenium values of serum and whole blood were determined for two groups of patients undergoing large surgical interventions (e.g., gastrectomy) and receiving a total parenteral nutrition (TPN). All patients showed low selenium values at the beginning of TPN. The first group received a supplementation of selenium, and it was established that selenium levels normalized after 6-7 d. The balances of selenium turned out to be positive in all cases. The second group, which was not administered selenium supplementation, showed significantly lower values of selenium. It can, therefore, be concluded that a substitution of selenium prior to large surgical interventions following TPN clearly helps patients combat the increase in the oxidant stress reactions.

Aged↗
PubMed1995

Ischemia induces early changes to cytoskeletal and contractile proteins in diseased human myocardium.

Ischemia is known to produce damage to subcellular organelles, such as nuclei and mitochondria, in myocardial tissue. We tested the hypothesis that during myocardial ischemia various cytoskeletal and contractile proteins also undergo changes. We induced total global ischemia by incubation in buffer of tissue samples from six human left ventricles that were obtained from heart transplant recipients. Samples were removed from the incubation medium at different time intervals and investigated by immunohistochemistry using monoclonal antibodies against myosin, actin, tropomyosin, troponin T, myomesin, desmin, tubulin, and vinculin. The degree of ischemic injury was determined by electron microscopy. Ischemic cardiomyopathic human tissue showed disturbances of the localization pattern of myosin, actin, tropomyosin, and troponin T as early as 10 minutes after the onset of ischemia; this disruption was complete at 20 minutes. Tubulin also started changing at 10 minutes, but complete disruption was only evident after 120 minutes. Desmin and myomesin showed an intermediate response; changes began at 30 to 40 minutes, and disruption was complete at 90 to 120 minutes. Vinculin was most resistant to ischemia. Ultrastructurally, the tissue showed moderate reversible ischemic injury during the entire period of 180 minutes. Measuring the exposure time in seconds allowed quantitation of the intensity of the fluorescence. We reached the following conclusions: (1) Ischemia causes damage to the contractile proteins sooner than to the cytoskeleton and subcellular organelles. (2) Diseased human hearts are extremely susceptible to the effects of ischemia. These findings are important for the situation of induced cardiac arrest in heart operations and for preservation of donor hearts for transplantation.

Actins↗
PubMed1995

[Interactions between cardiomyocytes and extracellular matrix in the failing human heart].

Numerous morphological changes can be observed in human myocardium failing because of dilated cardiomyopathy. These can be observed by electron microscopy and by immunofluorescence microscopy using monoclonal antibodies. These changes include: 1) the occurrence of hypertrophied and atrophied myocytes as well as cells of normal size, 2) degenerative changes in myocytes; these consist of nuclei of varying size and shape, lack of contractile material, disorganization of the cytoskeleton, and sequestration of cellular particles into the extracellular space and 3) an enlarged extracellular space, that is, fibrosis, which contains increased amounts of the different matrix proteins such as fibronectin and laminin, the various collagens, and chondroitin sulfate, in addition to cellular debris and numerous macrophages and fibroblasts. On the basis of these findings it is hypothetized that there exists an interaction between myocytes and the extracellular matrix. The cells of the latter may be stimulated to higher rates of proteins synthesis by the presence of cellular debris. This process, in turn, may be harmful for the structural integrity of myocytes which consequently sequester more cellular particles. In this manner, a vicious circle may be started that leads to further structural and functional deterioration of the myocardium, finally resulting in failure.

Cardiomyopathy, Dilated↗
PubMed1994

Altered expression of titin and contractile proteins in failing human myocardium.

Our own previous ultrastructural studies in human hearts with dilated cardiomyopathy and heart failure showed sarcomeric and cytoskeletal disarrangement. On the basis of these findings we tested the hypothesis that in cardiomyopathic failing hearts not only the sarcomere structure but also the organization and the amount of numerous contractile proteins are disturbed. Titin was included in this study because it is the elastic "third" filament of the sarcomere and also plays an important role as template for myosin and actin filaments in sarcomerogenesis. Human cardiac tissue obtained at the time of transplantation surgery was investigated using immunohistochemistry with monoclonal antibodies against titin, myosin, actin, tropomyosin, and troponin T. Additionally, isolated myocytes from rat or pig heart were used for the standardization of the localization pattern. In normal tissue, myosin and the thin filament complex showed a regular cross striation that was wider in myosin staining than for actin, troponin T, and tropomyosin corresponding with the different width of the A and I bands in the sarcomere. Titin localization in normal human and animal myocardium showed a regular cross striation pattern. In diseased cardiac tissue titin fluorescence intensity was reduced and frequently disorganization or almost complete loss of titin from many myocytes were present. Severe abnormalities of contractile proteins consisting of disarrangement or lack of filaments were also observed. Double staining procedures showed that in the same myocyte defects of the contractile apparatus were accompanied by a simultaneous reduction of titin indicating that the "third" sarcomeric filament system is involved in heart failure. Abnormalities of titin expression may be especially important because titin significantly influences sarcomeric elastic behaviour and is necessary as template for the organization of newly synthesized myosin and actin filaments. The loss of titin may contribute to the altered compliance in failing hearts. It is concluded that disorganization and loss of titin, myosin, and the thin filament complex are severe in the failing human heart because of dilated cardiomyopathy and that these changes may represent several of the most important components of the structural correlate of reduced cardiac function.

Adult↗
PubMed1994

Biochemical and molecular characterization of the Alcaligenes eutrophus pyruvate dehydrogenase complex and identification of a new type of dihydrolipoamide dehydrogenase.

Sequence analysis of a 6.3-kbp genomic EcoRI-fragment of Alcaligenes eutrophus, which was recently identified by using a dihydrolipoamide dehydrogenase-specific DNA probe (A. Pries, S. Hein, and A. Steinbüchel, FEMS Microbiol. Lett. 97:227-234, 1992), and of an adjacent 1.0-kbp EcoRI fragment revealed the structural genes of the A. eutrophus pyruvate dehydrogenase complex, pdhA (2,685 bp), pdhB (1,659 bp), and pdhL (1,782 bp), encoding the pyruvate dehydrogenase (E1), the dihydrolipoamide acetyltransferase (E2), and the dihydrolipoamide dehydrogenase (E3) components, respectively. Together with a 675-bp open reading frame (ORF3), the function of which remained unknown, these genes occur colinearly in one gene cluster in the order pdhA, pdhB, ORF3, and pdhL. The A. eutrophus pdhA, pdhB, and pdhL gene products exhibited significant homologies to the E1, E2, and E3 components, respectively, of the pyruvate dehydrogenase complexes of Escherichia coli and other organisms. Heterologous expression of pdhA, pdhB, and pdhL in E. coli K38(pGP1-2) and in the aceEF deletion mutant E. coli YYC202 was demonstrated by the occurrence of radiolabeled proteins in electropherograms, by spectrometric detection of enzyme activities, and by phenotypic complementation, respectively. A three-step procedure using chromatography on DEAE-Sephacel, chromatography on the triazine dye affinity medium Procion Blue H-ERD, and heat precipitation purified the E3 component of the A. eutrophus pyruvate dehydrogenase complex from the recombinant E. coli K38(pGP1-2, pT7-4SH7.3) 60-fold, recovering 41.5% of dihydrolipoamide dehydrogenase activity. Microsequencing of the purified E3 component revealed an amino acid sequence which corresponded to the N-terminal amino acid sequence deduced from the nucleotide sequence of pdhL. The N-terminal region of PdhL comprising amino acids 1 to 112 was distinguished from all other known dihydrolipoamide dehydrogenases. It resembled the N terminus of dihydrolipoamide acyltransferases, and it contained one single lipoyl domain which was separated by an adjacent hinge region from the C-terminal region of the protein that exhibited high homology to classical dihydrolipoamide dehydrogenases.

Alcaligenes↗
PubMed1992

Identification of a lipoamide dehydrogenase gene as second locus affected in poly(3-hydroxybutyric acid)-leaky mutants of Alcaligenes eutrophus.

From a genomic library of Alcaligenes eutrophus strain H16 in the broad-host range cosmid pVK100 a 6300-bp EcoRI-fragment was cloned, which restored the wild-type phenotype in transposon-induced poly(3-hydroxybutyric acid)-leaky mutants, derived from A. eutrophus. Nucleotide sequence analysis of the region adjacent to the transposon insertion revealed an open reading frame which complied with all criteria for a coding region. This region was referred to as phbL, and the deduced amino acid sequence from this part of phbL showed 60% amino acid identity in an overlap of 98 residues to the lipoamide dehydrogenase gene (lpd) of Escherichia coli. In addition, the 6300-bp EcoRI-fragment conferred expression of lipoamide dehydrogenase activity to E. coli.

3-Hydroxybutyric Acid↗
PubMed1991

Identification and partial characterization of the secretory glycoproteins of the bovine subcommissural organ-Reissner's fiber complex. Evidence for the existence of two precursor forms.

The subcommissural organ (SCO) is a brain gland whose secretory material is released into the cerebrospinal fluid where it condenses into a thread-like structure known as Reissner's fiber (RF). This fiber extends along the aqueduct, fourth ventricle and central canal of the spinal cord. The present investigation was designed to identify and partially characterize the secretory products of the bovine SCO in their intracellular location and after they have been released and packed into RF form. 5,000 SCOs were dissected out under a microscope, whereas RF of 30,000 cows were collected by perfusing the central canal of the spinal cord with artificial cerebrospinal fluid. Extracts of SCO and RF were used for (i) raising polyclonal antibodies; (ii) immunoblotting; (iii) lectin binding on electrotransfers: concanavalin A (affinity = mannose, glucose) and Limax flavus agglutinin (affinity = sialic acid); (iv) immunoaffinity chromatography; (v) preparative SDS-PAGE and raising of polyclonal antibodies against each of the secretory glycoproteins identified in the immunoblots. All antibodies and the two lectins were also applied to tissue sections of the SCO and RF of several species. The immunocytochemical study of the bovine SCO using an anti-RF serum showed that the secretory material present in the rough endoplasmic reticulum (RER), secretory granules and in RF is strongly immunoreactive. Con A binding sites were only found in the endoplasmic reticulum, whereas Limax flavus agglutinin revealed secretory granules and RF, only. In the blots the immunostaining was used to identify secretory polypeptides. The glycosylated nature of the latter was established by their affinity for Con A and/or Limax flavus agglutinin. Furthermore, this latter lectin allowed us to distinguish whether the intracellular source of a secretory glycoprotein is from a pre-Golgi (RER) or a post-Golgi (secretory granules) compartment. Four glycoproteins were identified in the SCO with apparent molecular weights of 540, 450, 320 and 190 kDa. The three former were also purified by immunoaffinity chromatography. The 540 and 320 kDa forms are present in the SCO but missing in RF, have affinity for Con A, but not for LFA. It is suggested that these two compounds correspond to two precursor forms. The 450 and 190 kDa glycoproteins are present in both, the SCO and RF, and have affinity for Con A and Limax flavus agglutinin. These most likely correspond to processed forms. The presence of more than one precursor was further substantiated by immunocytochemical findings using antisera against the 540, 450 and 320 kDa forms.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1991

Identification and molecular characterization of the Alcaligenes eutrophus H16 aco operon genes involved in acetoin catabolism.

Acetoin:dichlorophenolindophenol oxidoreductase (Ao:DCPIP OR) and the fast-migrating protein (FMP) were purified to homogeneity from crude extracts of acetoin-grown cells of Alcaligenes eutrophus. Ao:DCPIP OR consisted of alpha and beta subunits (Mrs, 35,500 and 36,000, respectively), and a tetrameric alpha 2 beta 2 structure was most likely for the native protein. The molecular weight of FMP subunits was 39,000. The N-terminal amino acid sequences of the three proteins were determined, and oligonucleotides were synthesized on the basis of the codon usage of A. eutrophus. With these, the structural genes for the alpha and beta subunits of Ao:DCPIP OR and FMP, which were referred to as acoA, acoB, and acoC, respectively, were localized on one single EcoRI restriction fragment which has been cloned recently (C. Fründ, H. Priefert, A. Steinbüchel, and H. G. Schlegel, J. Bacteriol. 171:6539-6548, 1989). The nucleotide sequences of a 5.3-kbp region of this fragment and one adjacent fragment were determined, and the structural genes for acoA (1,002 bp), acoB (1,017 bp), and acoC (1,125 bp) were identified. Together with the gene acoX, whose function is still unknown and which is represented by a 1,080-bp open reading frame, these genes are probably organized in one single operon (acoXABC). The transcription start site was identified 27 bp upstream of acoX; this site was preceded by a region which exhibited complete homology to the enterobacterial sigma 54-dependent promoter consensus sequence. The amino acid sequences deduced from acoA and acoB for the alpha subunit (Mr, 35,243) and the beta subunit (Mr, 35,788) exhibited significant homologies to the primary structures of the dehydrogenase components of various 2-oxo acid dehydrogenase complexes, whereas those deduced from acoC for FMP (Mr, 38,941) revealed homology to the dihydrolipoamide acetyltransferase of Escherichia coli. The occurrence of a new enzyme type for the degradation of acetoin is discussed.

Acetoin↗
PubMed1991

Impairment of the myocardial ultrastructure and changes of the cytoskeleton in dilated cardiomyopathy.

This study was designed to determine the morphological correlate of chronic heart failure. Myocardial tissue from eight patients undergoing transplantation surgery because of end-stage dilated cardiomyopathy was investigated by electron microscopy and immunocytochemistry using monoclonal antibodies against elements of the cytoskeleton: desmin, tubulin, vinculin, and vimentin. The tissue showed hypertrophy, atrophy of myocytes, and an increased amount of fibrosis. Ultrastructural changes consisted of enlargement and varying shape of nuclei, numerous very small mitochondria, proliferation of T tubules, and accumulation of lipid droplets and glycogen. The most obvious ultrastructural alteration was the decrease of myofilaments, ranging from rarefication to complete absence of sarcomeres in cells filled with unspecified cytoplasm. Immunocytochemistry showed that desmin was localized at the Z lines. In diseased myocardium, the amount of desmin was increased, but it was disorderly arranged. Tubulin formed a fine network throughout the myocytes and was significantly increased in cardiomyopathic hearts. Vinculin, a protein closely associated with the cytoskeleton, occurred not only at the sarcolemma and the intercalated disc but also within the myocardial cells. Ultrastructural changes and alterations of the cytoskeleton were severe in about one third of all cells. About one third of all cells showed moderately severe changes, and the remaining cells were normal. Vimentin was present in the interstitial cells and was increased in relation to the increase of fibrosis. We conclude that the increase of fibrosis, the degeneration of hypertrophied myocardial cells, and the alterations of the cytoskeleton are the morphological correlates of reduced myocardial function in chronic heart failure.

Antibodies, Monoclonal↗
PubMed1988

Pinealocytes immunoreactive with antisera against secretory glycoproteins of the subcommissural organ: a comparative study.

By means of light-microscopic immunocytochemistry two polyclonal antibodies (AFRU, ASO; see p. 470) directed against secretory glycoproteins of the subcommissural organ were shown to cross-react with cells in the pineal organ of lamprey larvae, coho salmon, a toad, two species of lizards, domestic fowl, albino rat and bovine (taxonomic details, see below). The AFRU-immunoreactive cells were identified as pinealocytes of the receptor line (pineal photoreceptors, modified photoreceptors or classical pinealocytes, respectively) either due to their characteristic structural features or by combining AFRU-immunoreaction with S-antigen and opsin immunocytochemistry in the same or adjacent sections. Depending on the species, AFRU- or ASO-immunoreactions were found in the entire perikaryon, inner segments, perinuclear area, and in basal processes facing capillaries or the basal lamina. In most cases, only certain populations of pinealocytes were immunolabeled; these cells were arranged in a peculiar topographical pattern. In lamprey larvae, immunoreactive pinealocytes were observed only in the pineal organ, but not in the parapineal organ. In coho salmon, the immunoreaction occurred in S-antigen-positive pinealocytes of the pineal end-vesicle, but was absent from S-antigen-immunoreactive pinealocytes of the stalk region. In the rat, AFRU-immunoreaction was restricted to S-antigen-immunoreactive pinealocytes found in the deep portion of the pineal organ and the habenular region. These findings support the concept that several types of pinealocytes exist, which differ in their molecular, biochemical and functional features. They also indicate the possibility that the AFRU- and ASO-immunoreactive material found in certain pinealocytes might represent a proteinaceous or peptide compound, which is synthesized and released from a specialized type of pinealocyte in a hormone-like fashion. This cell type may share functional characteristics with peptidergic neurons or paraneurons.

Animals↗