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Biomedical subjects

H Matthies

Publications and source records attributed to H Matthies.

At least 127 records · Page 7Linked to original sources
PubMed1982

Apomorphine and glycoprotein synthesis during consolidation.

The dopamine agonist, apomorphine, was injected intrahippocampally immediately after acquisition of a brightness discrimination task, which was motivated by footshock in rats. This led to an increase in the incorporation of L-fucose into total proteins which were measured in the hippocampus 7-9 hours later. In behavioral experiments, the same application improved the retention of a learned task. A possible linkage between increased glycoprotein synthesis and improvement of the retention of a new learned behavior due to the action of apomorphine is discussed.

Animals↗
PubMed1982

Distribution of hippocampal glycoproteins as demonstrated in rats by lectin binding and autoradiography after intraventricular injections of labelled fucose, N-acetyl-glucosamine and mannose.

The present study demonstrates distinct distribution patterns of glycoproteins in rat hippocampus, with respect to synthesis from precursors (autoradiography) and endogenous contents (lectin binding). The autoradiographic analysis performed 1, 2, 8 and 24 h after intraventricular injections of tritium-labelled L-fucose. N-acetyl-D-glucosamine and D-mannose revealed that up to 2 h after application of any of the three precursors, radioactivity occurred in the pyramidal and granular cell layers. Afterwards, however, rapid migration of label proceeded from the cell bodies into the neuropil after application of fucose and acetylglucosamine, while after injection of mannose a considerable amount of radioactivity stayed in the cell body layers, even 24 h after administration of labelled precursor. These findings were consistent with the histochemical visualization of glycoprotein constituents by fluorescent wheat germ lectin (preferentially binding to glucosaminyl residues) and concanavalin A-horseradish peroxidase (preferentially binding to mannosyl residues). These showed a heavy staining predominantly in neuropil and somata, respectively, with concanavalin A-binding giving more distinct patterns than the application of labelled mannose. The usefulness of the three glycoprotein precursors as correlates with functional behavioural changes in discussed.

Acetylglucosamine↗
PubMed1982

Effect of substance P on the retention of a brightness discrimination task in rats.

The effect of substance P (SP) on acquisition and retention of a footshock-motivated brightness discrimination was investigated in rats, 250 micrograms SP/kg were injected intraperitoneally either 30 min before or immediately after the training session. Acquisition of the brightness discrimination was not affected by SP administered 30 min before training. However, both the pre-training and post-training injections of SP resulted in a significant improvement of retention tested 24 h after training. The effect of SP on memory consolidation is discussed.

Animals↗
PubMed1982

Effect of methylglucamine orotate on intracranial self-stimulation.

The effect of the memory improving substance methylglucamine orotate (MGO) on intracranial self-stimulation was investigated in rats. Self-stimulation (0.2 mn square pulses; 100 Hz frequency; 400 mn chain; 100-300 micro A current) was performed using electrodes in the lateral hypothalamus. MGO was administered intraperitoneally in doses of 112.5 mg/kg and 225 mg/kg or intraventricularly in a dose of 225 micrograms per rat. In chronic experiments, daily intraperitoneal injections of 225 mg/kg MGO were given during 10 days. The results show that intracranial self-stimulation is scarcely influenced by a single injection of retention improving MGO doses, but increased significantly by repeated MGO application.

Animals↗
PubMed1981

Improvement of shuttle-box avoidance by combinations of orotic acid and central stimulants.

The effect of orotic acid and central stimulants on retention of shuttle-box avoidance was investigated in rats. Orotic acid (100 mg/kg) was injected 30 min before training; caffeine (20mg/kg), strychnine (1 mg/kg), or methylphenidate (10 mg/kg) were injected immediately after training. When given alone, these drugs improved avoidance retention when tested 24 h after training. However, improvement of retention was much more evident when orotic acid was given in combination with a stimulant. The data are discussed in relation to the role of macromolecule synthesis and arousal in memory formation.

Animals↗
PubMed1981

Dopamine induced changes in L-fucose incorporation into proteins of rat hippocampus and corpus striatum during postnatal development.

In 60 day old (adult) male Wistar rats dopamine caused a dose-dependent increase of L-fucose incorporation into total proteins of both hippocampus and corpus striatum slices up to +47.8 +/- 6.0% (n=6) and +53.2 +/- 8.5% (n=20), respectively, when compared to corresponding controls. Under these conditions the dopamine concentration leading to a maximum stimulation of fucose incorporation was 5 X 10(-4) M in hippocampus and 1 X 10(-3) M in corpus striatum. In the latter tissue the range of dopamine concentrations causing a significant elevation in incorporation rates was larger than in hippocampal tissue. In the corpus striatum of 9 day old rats dopamine was ineffective, but by 30 days the transmitter stimulated fucose incorporation rate reached the maximum observed for any age studied. This developmental pattern seems to be related to the ontogenesis of dopamine receptor sites or dopamine sensitive adenylate cyclase formation in this brain structure. In the hippocampus the postnatal development of dopamine induced augmentation of glycoprotein synthesis showed a longer latency, but the maximum effect was also seen in 30 day old animals. These results support our assumption that at the end of the postnatal differentiation period the glycoprotein synthesis in brain tissue may be controlled (at least to some extent) by the state of dopaminergic receptors and/or of dopamine sensitive adenylate cyclase.

Animals↗
PubMed1981

[The effect of conditioning on the ultrastructural distribution of synaptic vesicles in the hippocampus of the rat].

In three months old male Wistar-rats the influence of conditioning (brightness discrimination reaction) on the number and distribution of vesicles of the synapses in the stratum radiatum (CA 3) of the hippocampus were investigated. A total of 15 rats (5 trained rats, 5 passive and 5 active controls) were studied by the aid of electron microscopic and morphometric methods. The number of synaptic vesicles was evaluated for the passive controls by 27 vesicles per synaptic area. In the CA 3-region 70 minutes after training the calculation of the number of synaptic vesicles revealed a significant decrease in comparison with passive and active controls (16 and 32 vesicles per synaptic area, respectively; significant difference at p less than 0.05). The volume of the synaptic vesicles was reduced for the trained rats by 20-25% in comparison with controls. The morphological results after training could be correlated with the changes of the Ach fractions, and seem to be of great significance at the initial stages of memory formation.

Acetylcholine↗
PubMed1980

The influence of dopamine on the incorporation of different sugars into total proteins of hippocampal slices.

Dopamine increases the incorporation of L-fucose and of D-mannose to a similar significant degree, whereas the incorporation of D-galactose as well as of N-acetyl-D-glucosamin into the total proteins of hippocampal slices was only slightly enhanced. The incorporation of N-acetyl-neuraminic acid was not influenced by dopamine. The results suggest that the effect of dopamine on glycoprotein formation seems mainly to depend on the kind of nucleotides necessary for activation of sugars and not on the sugar's final position in the glycan chain.

Animals↗
PubMed1980

Choline uptake and permanent memory storage.

The uptake of 3H-choline and its incorporation into 3H-acetylcholine was studied in vitro on hippocampus slices obtained from animals showing a good or poor long-term memory. The animals were selected on the basis of their retention performance when tested by a brightness discrimination model. The 3H-choline uptake and the incorporation of 3H-choline into 3H-acetylcholine was higher in hippocampus slices from animals showing good retention compared to those from animals with poor retention. The level of high affinity uptake of choline into hippocampus slices may serve as an indicator of the cholinergic activity in this structure under in vitro conditions. The present findings suggest that individual differences in the activity level of the hippocampal cholinergic system do exist and are capable of influencing the retention of the individual animals to a variable degree.

Acetylcholine↗
PubMed1980

Two sensitive periods for the amnesic effect of anisomycin.

Impairment of retention of a brightness discrimination in rats was obtained when anisomycin (80 microgram bilaterally into both hippocampi) was injected 10 min before and 80 min after training or 240 and 360 min after training. No amnesia was observed when anisomycin was injected 45 and 165 min post training. The two separate sensitive periods for the amnesic effect of the inhibitor obviously correspond to the two phases of increased protein synthesis during the consolidation of the same learning procedure. The results support the previous findings of the two independent and qualitatively different macromolecular processes. They also argue for the inhibition of protein synthesis as an important mechanism in the amnesic effect of anisomycin.

Animals↗
PubMed1980

Effect of L-fucose on brain protein metabolism and retention of a learned behavior in rats.

The intraperitoneal or intraventricular application of L-fucose (100 mg/kg or 75 microgram, respectively) prior to training in shuttle box avoidance as well as in shock-motivated brightness discrimination in rats significantly improved the retention of learned behavior 24 hr later. The application of D-fucose was without influence on retention. In naive animals, intraventricularly applied L-fucose (75-200 microgram) caused an increase in the rate of protein synthesis in the hippocampus, resulting in a significant increase in total proteins of this brain structure, mainly attributed to the Tris-insoluble protein fractions. The results are discussed in terms of an activation of glycoprotein formation by increasing supply with L-fucose.

Animals↗