Search PubMed⌕ Search

Biomedical subjects

H Luppa

Publications and source records attributed to H Luppa.

At least 37 records · Page 2Linked to original sources
PubMed1984

[Immunohistochemical studies of the occurrence and localization of somatostatin in the hippocampus formation of Wistar rats].

In the hippocampus formation of Bouin fixed and paraffin embedded specimens of Wistar rats somatostatin-immunoreactive cells could be demonstrated regularly in the hilus region. Some cells indicating immunoreactivity have been observed in the stratum radiatum of the CA1- and CA2-regions. On the basis of light microscopic investigations it was not possible to decide whether somatostatin-immunoreactivity is located in the cytoplasm of the cells or in surrounding axon-terminals.

Animals↗
PubMed1982

Multiple localizations of adenylate cyclase in rat hippocampus. A histochemical study.

A new method for the histochemical demonstration of adenylate cyclase activity, introduced and biochemically tested by Poeggel et al. (1981 a), was employed in nervous tissue. Using this method a multiple pattern of activity was detectable. Activity occurs in nervous as well as glial elements. Biochemical results and physiological conclusions could be confirmed by ultrahistochemical visualization of adenylate cyclase activity in nervous tissue. The specificity of the reaction is controlled by a number of variations of the incubation methods.

Adenylyl Cyclases↗
PubMed1982

[Histochemical and biochemical investigations of the hippocampus and neocortex of the wistar rat. III. Electron-microscopic investigations on the localization of non-specific esterases in the hippocampus (author's transl)].

This report describes the ultrastructural localization of the non-specific esterases in the pyramidal cells of the CA3-region of rat hippocampus. The use of specific inhibitors allowed the differentiation between aryl-, carboxyl- and acetylesterases. The thiolacetic acid reaction at pH = 5.2 and 7.0 proved to be a favourable method for the conditions of the hippocampus. Liver tissue served for control purposes. In the pyramidal cells carboxylesterase could be demonstrated on membranes and cisternes of the endoplasmic reticulum on polysomes and in the nuclear envelope. Arylesterase was localized in numerous synaptic vesicles and in the myeline sheath of axons. In lysosomes and in mitochondria an esterase activity was demonstrable, which behaved like an acetylesterase. In the hippocampus carboxylesterase could be shown only at pH = 7.0, whereas in liver this enzyme also give a clear reaction at pH = 5.2. Aryl- and acetylesterase reacted at both pH-ranges in the hippocampus. Biochemical investigations showed that the tissue pretreatment, which is necessary for the ultrahistochemical demonstration of nonspecific esterases considerable decreased the enzyme activity. Formaldehyde and glutaraldehyde have thereby a different action on the several esterase types.

Animals↗
PubMed1981

Specific demonstration of rat brain adenylate cyclase in polyacryl amide microgels by a new histochemical procedure.

Adenylate cyclase from rat hippocampus was separated by electrophoresis in polyacryl amide microgels and stained for enzymatic activity using a new histochemical procedure. This method involves the use of AMP-PNP, aminophylline, dithiotreitole, and Sr2+ as "primary" capture ions, thus fulfilling all the demands for a really specific histochemical incubation medium for the enzyme. The incubation of the gels with this medium resulted in the inhibition of other enzymes, which are capable of splitting AMP-PNP (ATP: pyrophosphatase, alkaline phosphatase), whereas adenylate cyclase remained highly active under these conditions. The enzyme was found to be present in two forms in the gels. Both protein bands were stimulated by the addition of various biogenic amines to the incubation medium. One protein band was fully GMP-PNP dependent in its activity. It is reasonable to suppose that these forms are either differently high aggregated molecules of the enzyme or enzyme molecules bound to their regulatory sites.

Adenylyl Cyclases↗
PubMed1980

Failure to demonstrate rat hippocampus adenylate cyclase.

The fate of ATP exposed to rat hippocampal extracts was investigated after their separation by a microdisc electrophoresis tenhnique. It could be demonstrated that the histochemical adenylate cyclase procedure using ATP as substrate is not suitable for specific localization of the enzyme, since other ATP hydrolysing enzymes were also able to convert ATP unless the concentrations of inhibitors reached 1 mM (ouabain) and 40 mM (NaF). With a prolonged incubation time of 18 h further substrate splitting protein zones could be revealed, possibly reflecting activities of enzymes involved in the hydrolysis of degradation products of ATP.

Adenosine Triphosphate↗
PubMed1980

[Histochemical and biochemical investigations of the hippocampus and neocortex of the Wistar rat. I. Carboxylic ester hydrolases, transmitter enzymes and transmitters of the normal animal (author's transl)].

Some enzymatic parameters of neuronal transmission as well as the occurrence and the properties or carboxylic ester hydrolases in the hippocampal region of the wistar rat are investigated by histochemical and comparable biochemical methods. The acetylcholinesterase-, the monoamine oxidase- and the GABA-transaminase reaction are found at fibre structures, the course of which is seen more or less clearly. The histochemical picture of these enzymes is very different in each hippocampal layer and mainly limited by the corresponding number of reacting fibres. The origin and attribution of the fibres to the afferent and efferent systems are discussed. The occurrence of the acetylcholinesterase, the monoamine oxidase and the GABA-transferase as well as of the biogenic amines and the GABA are hints for the existence of cholinergic as well as aminergic and GABA-ergic processes of transmission in the hippocampal region. In the hippocampal region, the cingular and the optic cortex carboxylic ester hydrolases acetylcholinesterase, unspecific cholinesterase and the A-, B- and C-esterase could be demonstrated. The acetylcholinesterase of the hippocampal region is for the most part firmly membrane-bound and exists at least in two multiple, formalin-sensitive forms which are histochemically located in fibre structures. The unspecific cholinesterase, localized in the hippocampal region within vessel and capillary walls, exists in an electrophoretic mobile, formalin-sensitive form. Nearly half of the enzymes is soluble. A preferred binding to definite cell organelles was not demonstrable. In the hippocampal region the 3 multiple forms of the A-esterase are formalin-instable lyoenzymes. Good solubility and high formalin-sensitivity are the reason, why A-esterases are not demonstrable with usually histochemical methods. In the hippo ampal region the B-esterase is tightly bound to n electrophoretic mobile formalin-sensitive form in the microsomal fraction. In the cytoplasm of the neurones the desmoenzyme appears more or less granular. The 3 multiple forms of the C-esterase are formalin-sensitive to a different degree. Good solubility and low formalin-sensitivity, compared to the A-esterases are responsible for the fact, that the C-esterases can be shown histochemically only after en-bloc-fixation. The reaction products are granular. The similar behaviour of C-esterase and acid phosphatase, stated by many tests, suggests the C-esterases of the B- and C-type results in the same reactivity of pyramidal and granular cells of the hippocampal region. Some small, very strongly reacting cells belong to other cell types (probably basket cells or polymorphic cells).

4-Aminobutyrate Transaminase↗
PubMed1980

[Histochemical and biochemical study of the hippocampus and neocortex of the wistar rat. II. The activity of carboxylic acid esterases and transmitter enzymes after a learning experiment].

In the present paper the behaviour of the enzymes monoaminoxidase, GABA-transaminase, acetylcholinesterase, nonspecific cholinesterase, A-, B-, C-esterase and acid phosphatase was investigated by histochemical and biochemical methods for 1 min, 1, 4 and 24 h after a "brightness-discrimination" of male wistar rats in a Y-chamber. Learning induced significant changes of activity of the B-esterase in the hippocampus region 4 h (increase of 30%) and 24 h (decrease of 25%) and of the acetylcholinesterase in the cingular cortex 4 h after training (increase of 38%) are to be observed and regarded and discussed as hints for a changed protein synthesis (B-esterase) or altered synaptic activity (acetylcholinesterase). On the strength of these results and various findings in the literature it may be reputed as sure, that the protein synthesis of the cells of hippocampus in evident. Certain proteins show increased rates of synthesis by the influence of a learning experiment. These proteins are at least partially enzymes, serving as extension of the protein synthesis apparatus of the neurons and may be regarded as part mechanism of the intracellular regulation of the synaptic connectivity.

4-Aminobutyrate Transaminase↗
PubMed1979

The multiple forms of brain acetycholinesterase. III. Implications for the histochemical demonstration of acetylcholinesterase.

The multiple forms of acetylcholinesterase (AChE, E.C. 3.1.1.7) have been investigated with regard to their histochemical demonstrability. Their pattern is influenced by buffer treatment, fixation, and by incubation conditions causing aggregation and disaggregation as well as loss or inactivation of individual forms. The standard histochemical method for AChE preferentially demonstrates the high molecular forms. Most of the oligomer forms are washed out or inactivated. A selective demonstration of the highly aggregated forms is possible either by inhibition of the oligomers with diisopropylfluoridate (DFP) or by specifically dissolving them out. No reason could be found for the selective demonstration of the low molecular weight forms.

Acetylcholinesterase↗
PubMed1979

[Electron-microscopic investigations on the localisation of the thiamine pyrophosphatase in the hippocampus of the Wistar rat (author's transl)].

This report describes the ultratopochemical localization of the thiamine pyrophosphatase in the pyramidal cells of the CA3 region of Wistar rat hippocampus. Attention was focussed on the occurrence of the enzyme out of the Golgi field. Thiamine pyrophosphatase was demonstrated in dendrites and - to a lesser extent - in axons. TTPase containing synapses were rather seldom and belonged to the axo-dendritic type. A hypothetic model concerning the transport and the distribution of the enzyme within the cell is presented.

Animals↗
PubMed1979

Is thiamine pyrophosphatase a reliable marker of the neuronal Golgi apparatus? A critical analysis.

The thiamine pyrophosphatase histochemical technique is believed to be a suitable approach to the selective staining of the Golgi vesicles of all animal cells, icluding the neuron. However, during the past decade a considerable number of data have been published, suggesting that the TPPase is in general a membrane-associated enzyme in the brain, which can be found in subcellular fractions other than Golgi lamellae. It has therefore become necessary to reconsider the view that thiamine pyrophosphatase is an exclusive marker enzyme of the Golgi apparatus.

Animals↗
PubMed1978

Isoelectric focusing studies on the neutral 5'-nucleotidase from Wistar rat hippocampus: evidence for the absence of isoenzymes.

The pattern and some substrates characteristic of the rat brain 5'-nucleotidase were studied using the isoelectric focusing technique, which revealed that the enzyme is present in a single form in hippocampus extracts. An alkaline phosphatase, which is also able to split nucleoside monophosphates, is not active at neutral pH values. The isoelectric points were found to be 6.4 +/- 0.1 for the specific 5'-nucleotidase and 6.8 +/- 0.1 for the phosphatase.

Alkaline Phosphatase↗
PubMed1978

Cytochemical investigations on the localization of 5'-nucleotidase in the rat hippocampus with special reference to synaptic regions.

The fine structural localization of the 5'-nucleotidase was investigated in the CA3 region of the rat hippocampus. The attention was focussed on the occurrence of the enzyme in the synaptic region. The 5'-nucleotidase activity was demonstrated at the surface membranes of axons and dendrites. Prominent portions of enzyme activity were detectable in the nuclei and the nuclear envelope, whereas the cytoplasmic organelles were nearly devoid of reaction product. In synapses five types of 5'-nucleotidase localization were revealed. A participation of the enzyme in the process of neurotransmission is discussed.

Animals↗
PubMed1978

The multiple forms of brain acetylcholinesterase. II. A suggestion of their functional importance.

The pattern of the multiple forms of the acetylocholinesterase (AChE, E.C. 3.1.1.7) of the rat brain is investigated using polyacrylamide gradient micro-gel electrophoresis with regard to a possible functional importance of this individual forms. The patterns of the AChE-forms of selected regions of the CNS are compared and certain differences could be shown. After increased cholinergic input (into the hippocampus by electrical stimulation of the nc. septi medialis) an aggregation of AChE subunits is detectable. Subletal intoxication with an irreversible inhibitor of AChE is followed by a faster recovery of the smaller forms. A suggestion of a possible functional role of the multiple forms of AChE is discussed.

Acetylcholinesterase↗
PubMed1977

The multiple forms of brain acetylcholinesterase. I. Micro-electrophoresis and topochemical analysis of the pattern.

Micro-polyacrylamide gradient electrophoresis followed by active staining is applied for the demonstration of the multiple forms of acetylcholinesterase. Among other advantages the very small samples that enable the analysis of well-defined brain material as well as the almost histochemical conditions of incubation enable its successful use in topochemical investigations of the multiple form pattern of brain acetylcholinesterase. The acetylcholinesterase of bovine nc. caudatus could be separated into 4 multiple forms and the pattern was analysed microdensitometrically. These forms differ in their molecular weight as well as in their degree of membrane binding. Increasing ionic strength (NaCl) is followed by changes in the pattern. This result is discussed as caused by aggregation of enzyme subunits.

Acetylcholinesterase↗
PubMed1977

Demonstration of acetylcholinesterase by semipermeable membrane technique: estimation of soluble and fixation-labile portions in different regions of the central nervous system.

A histochemical method for the demonstration of acetylcholinesterase using semipermeable membranes is described. This technique prevents any loss of enzyme activity caused by dissolution and/or fixation. The soluble and fixation-labile portions of acetylcholinesterase were estimated in several regions of the central nervous system of the rat and differences were found. The method improves the accuracy of the histochemical demonstration of the acetylcholinesterase on the light microscopical level.

Acetylcholinesterase↗