Inhibition of the Larmor precession during optical pumping in a weak magnetic field.
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Journal Article↗
Biomedical subjects
R Morgenstern
Publications and source records attributed to R Morgenstern.
Comment on "Emission-angle-dependent post-collision interaction"
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Journal Article↗
The essential sequence of substance P for locomotion.
In rats the effect of substance P SP (1-11 and SP (5-11) heptapeptide on locomotion in open field was investigated after intrategmental application. SP (1-11) increase the locomotor activity significantly, SP (5-11) heptapeptide do not-do it. The effect of SP(1-11), SP(5-11) heptapeptide, SP(6-11) hexapeptide, and SP(1-4) tetrapeptide on the circadianly organized locomotor activity was researched after i.p. application at 11 a.m. (light phasis, low activity of rats) or 7 p.m. (dark phasis, high activity). An increased effect on locomotiou'slow activity of rats appears by SP(1-11) and SP(1-4) tetrapeptide application for several hours in light time. Both peptides display a decreasing effect on locomotion after application for several hours in dark time, too. SP(5-11) heptapeptide and SP(6-11) hexapeptide do not have any influence on locomotion. The effects of SP(1-11) are equal to results found after application into the ventral tegmental area. The experimental results display that SP acts as a regulatory peptide modulating the activity of rats by a levelling mechanism. The N-terminal SP-sequence, SP(1-4), acts in a similar manner. The effects are discussed in relation to the mediation by receptors which recognize the C- or N-terminal part of the SP molecule.
Amino Acid Sequence↗
Behavioral function of GABA in the median raphe nucleus.
Locomotor hyperactivity of rats was induced by injection of muscimol into the median raphe nucleus. Intra-raphe injection of picrotoxin or bicuculline failed to influence locomotor activity, however, muscimol-induced hyperactivity was inhibited by simultaneous intra-raphe injection of picrotoxin and muscimol. These data indicate an involvement of the GABAergic system in the median raphe nucleus in induction of locomotor effects. Systemic and intra-raphe injection of cyproheptadine depressed muscimol-induced hypermotility, whereas lesion of serotonergic raphe neurons by 5,7-DHT or intra-raphe injected LSD did not influence the muscimol effect, suggesting that GABAergically induced locomotor effects are not entirely mediated by serotonergic mechanisms.
Animals↗
Microsomal glutathione transferase. Primary structure.
The primary structure of rat liver microsomal glutathione transferase has been determined. The 14C-carboxymethylated protein was fragmented with CNBr and proteolytic enzymes. The basis of the analysis was information from sequenator degradations of the intact protein, the largest CNBr fragment, and a large COOH-terminal fragment derived from a digest with Glu-specific staphylococcal protease. Remaining, smaller fragments were analyzed with the manual dimethylaminoazobenzene isothiocyanate method. Pepsin and limited acid hydrolysis were used to obtain peptides to confirm and overlap hydrophobic structures in the COOH-terminal half of the protein where trypsin and chymotrypsin failed to give any cleavage. Combined, these data permit the deduction of a 154-residue amino acid sequence. No evidence for micro-heterogeneity was obtained. The NH2-terminal alanine residue has a free alpha-amino group and the cysteine residue involved in activation of the enzymatic activity by sulfhydryl reagents is at position 49. The protein chain contains three regions with predictions for long beta strand secondary structures (positions 11-26, 103-120, and 131-145). Predictions may be inaccurate in membrane-associated proteins, but two of these regions also affect the three most hydrophobic segments. Thus, residues 11-35 form a long, largely hydrophobic part interrupted by only one charged residue (Lys-25), and residues 81-97 and 114-126 constitute the most hydrophobic segments directly noticeable from the hydrophilicity curve of the protein chain. These special parts of the molecule are of interest in relation to membrane interactions.
Amino Acid Sequence↗
Locomotor effects of lisuride: a consequence of dopaminergic and serotonergic actions.
The open-field test was used to study the involvement of serotonergic and dopaminergic mechanisms in the action of lisuride on locomotor activity in the rat. Lisuride produced a biphasic locomotor effect. The maximum locomotor stimulatory response of lisuride was stronger than that of apomorphine and comparable with that of apomorphine and LSD combined. Hypermotility induced by high doses of lisuride was partially suppressed by the serotonin antagonist cyproheptadine and not further enhanced by LSD. A moderate dose of lisuride potentiated apomorphine-induced hypermotility in the same manner as has been shown for LSD. Lesion of dopaminergic structures within the median raphe nucleus by 6-OHDA produced a potentiation of lisuride-induced hypermotility. This effect was suppressed by cyproheptadine. The locomotor inhibitory effect of low doses of lisuride may be related to a stimulation of presynaptic mesolimbic dopamine receptors. It is concluded that the locomotor stimulant effect of higher doses of lisuride may depend on stimulation of postsynaptic dopamine receptors and a serotonergic action and that the locomotor effects of lisuride reflect a complex interaction at dopaminergic and serotonergic transmission systems.
Animals↗
Sulpiride blocks postsynaptic dopamine receptors in the nucleus accumbens.
Intra-accumbens injection of sulpiride, tiapride, and metoclopramide antagonized locomotor hyperactivity induced by intraperitoneal administration of apomorphine in rats and measured over the first five minutes after introducing the animal to an open-field cage. Sulpiride was slightly more potent than tiapride which was more than 10 times more potent than metoclopramide and haloperidol. The threshold dose of sulpiride was as low as 0.001 microgram, bilaterally. Intra-accumbens injection of sulpiride also blocked exploratory hypermotility induced by bilateral intra-accumbens injections of apomorphine and picrotoxin. The threshold dose of sulpiride for blocking these two effects was about 0.01 microgram, bilaterally. Sulpiride was more than 10 times more potent than haloperidol in blocking this apomorphine-induced hypermotility. Haloperidol did not influence the picrotoxin hypermotility. The results obtained indicate strong postsynaptic dopamine antagonist properties of sulpiride, tiapride and metoclopramide.
Animals↗
Effect of a novel environment on locomotor hyperactivity of rats induced by apomorphine in the nucleus accumbens.
Bilateral local injections into the nucleus accumbens of apomorphine in doses between 0.125 and 20 micrograms produced a dose-dependent increase of locomotor activity in rats recorded over the first 5-min period after placing the animals in a novel environment 7 min after the injection. Continuous records over consecutive 5-min periods revealed that the locomotor effect of apomorphine (1 microgram, bilaterally) declines rapidly within less than 30 min. Progressively weaker locomotor hyperactivity in the first 5-min periods was observed after prolongation of the interval between intra-accumbens injection of apomorphine and the commencement of testing from 7 to 12, 17 and 22 min, respectively. Since no difference was found between locomotor activity of animals just placed in the novel environment and that of animals already present in this environment for one or more periods of record at fixed times after the injection, it is concluded that exploration does not contribute to locomotor hyperactivity induced by intra-accumbens injections of apomorphine.
Animals↗
The distribution of microsomal glutathione transferase among different organelles, different organs, and different organisms.
In the present study we have used both enzyme assay with 1-chloro-2,4-dinitrobenzene as substrate and immunochemical quantitation to examine the distribution of microsomal glutathione transferase in different organelles, in different organs, and in different organisms. This enzyme was found to constitute 3% and 5%, respectively, of the total protein recovered in the microsomal and outer mitochondrial membrane fractions from rat liver. Microsomal glutathione transferase present in other subcellular fractions can be accounted for by contamination by the endoplasmic reticulum. In contrast to the situation with rat liver microsomes the glutathione transferase activities of microsomes from extrahepatic tissues of this same animal could not be activated by treatment with N-ethylmaleimide. Nonetheless, significant albeit low levels of a protein with the same molecular weight and immunochemical properties as the rat liver enzyme could be detected in microsomes from several extrahepatic tissues, notably the intestine, the adrenal, and the testis. Of those mammals for which fresh liver could be obtained, all demonstrated N-ethylmaleimide-activatable glutathione transferase activity in their liver microsomes. On the other hand, representatives for fish, birds, and amphibia did not demonstrate such activatable transferase activity in their liver microsomes. Toad was the only species that had a notable (twofold) sex difference in their level of hepatic microsomal glutathione transferase activity.
Animals↗
The role of the median raphe nucleus in sulpiride-induced potentiation of apomorphine hypermotility.
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Animals↗
Comparison of two methods for estimating the acetylcholine turnover in discrete rat brain structures.
The acetylcholine turnover rate was determined in olfactory tubercle, nucleus accumbens and striatum of rat brain. The calculation of turnover rates was carried out by means of two different methods: a two compartment analysis and the finite differences method. After pulse injection of [3H]choline the radioactivity of both [3H]acetylcholine and [3H]choline was measured in the above mentioned brain areas. The contents of acetylcholine and choline were measured radioenzymatically. By using the two compartment model the following acetylcholine turnover rates were obtained: olfactory tubercle, 0.577; nucleus accumbens, 0.679; striatum, 1.110 (mumoles/g X hr). When using the finite differences method the values were: olfactory tubercle, 0.517; nucleus accumbens, 0.822; striatum, 1.115 (mumoles/g X hr). This demonstrates that the results obtained by applying the two different methods are nearly identical. Advantages and disadvantages of the two methods are discussed.
Acetylcholine↗
Clozapine--a serotonin antagonist?
The effect of clozapine on the central serotonergic transmission system was studied by investigation of open-field motility of rats after microinjection of drugs into nucleus accumbens and median raphe nucleus. Previous work has shown that LSD in low doses potentiates apomorphine-induced hypermotility and that this LSD effect is induced by a serotonin agonist action in median raphe nucleus. Clozapine, injected into median raphe nucleus (0.05 micrograms), suppressed the LSD effect in the same manner as serotonin antagonists did. Since alpha-adrenergic drugs, injected into median raphe nucleus, caused locomotor stimulant effects, an alpha- adrenalytic action of clozapine was excluded. Clozapine, injected into nucleus accumbens (0.2 micrograms), increased apomorphine-induced hypermotility, whereas the dopamine antagonist haloperidol suppressed it. Our results suggest a serotonin antagonist action of clozapine.
Animals↗
Drug-induced modulation of locomotor hyperactivity induced by picrotoxin in nucleus accumbens.
Locomotor hyperactivity was induced in rats by bilateral injection of picrotoxin (PIC) into the nucleus accumbens (NAC) followed by intraperitoneal (IP) or intra-accumbens (IA) injection of agents affecting dopamine (DA), acetylcholine, serotonin, or GABA receptors. IP injection of haloperidol and diazepam attenuated PIC-induced hypermotility in a dose-dependent manner. Low (sedative) doses of the DA agonists apomorphine (APO) and lisuride, or pretreatment with reserpine abolished PIC-induced hypermotility. Independent of a preceding IA injection of PIC, higher IP doses of APO produced the well-known locomotor effect. LSD, and the atypical neuroleptic, sulpiride, potentiated PIC-induced hypermotility strongly whereas clozapine was ineffective. IA injection of carbachol or haloperidol, in doses which antagonized hypermotility induced by APO IP, did not influence PIC-induced hypermotility. The atypical neuroleptics, clozapine and sulpiride, and the benzodiazepine, diazepam, inhibited PIC-induced hypermotility. The results suggest that there is a complex involvement of GABA, DA and serotonin functions in the effectuation of PIC-induced hypermotility and that PIC-induced hypermotility may be affected by DA-sensitive structures situated outside the NAC.
Animals↗
Induction of xenobiotic-metabolizing enzymes by trans-stilbene oxide and 2-acetylaminofluorene: observations on enzyme induction by drugs.
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2-Acetylaminofluorene↗
Induction of cytosolic glutathione transferase and microsomal epoxide hydrolase activities in extrahepatic organs of the rat by phenobarbital, 3-methylcholanthrene and trans-stilbene oxide.
The effects of treating male Sprague-Dawley rats with phenobarbital, 3-methylcholanthrene or trans-stilbene oxide on cytosolic glutathione transferase and microsomal epoxide hydrolase activities in the liver, intestine, kidney, lung, testis, adrenal, spleen, heart and brain have been investigated. Studies on the time-courses of induction in liver demonstrate that these are complete after five days' treatment at the doses used. Phenobarbital induces both cytosolic glutathione transferase and microsomal epoxide hydrolase activities significantly only in liver and intestine. 3-Methylcholanthrene induces these activities in liver only. Trans-Stilbene oxide induces both of these activities in liver and kidney, and cytosolic glutathione transferase activity in adrenal as well.
Animals↗
[Basic research on ultrasound surgery. VI: Comparative histological liver findings following treatment of the wound with ultrasound welding and suturing].
Liver cuts were performed on 21 Mini- Lewe pigs and then closed with suture in one case, and by ultrasonic welding of Fimomed - Gelaspon conglomerate in the other. Macroscopic assessment in situ and the histological examination of cut out liver areas regularly showed perifocal inflammatory peritoneal reactions and abscess formation for the sutured regions. From a histological point of view the liver tissue in the regions subjected to ultrasonic treatment reacted more strongly than after suture, particularly in the form of lobule structure disturbances, focal hepatitis, hepatic duct proliferation and destruction, and cholangitis. All of these were limited to the immediate vicinity of the conglomerate with its fibrous demarcation, which remained identifiable until the end of the experiment after a year and a half. The experiments resulted in the sucessful closure of the liver wounds in all cases where ultrasonic welding of Fimomed - Gelaspon compound was used. Application to human medicine is, however, not yet justified.
Animals↗
The amount and nature of glutathione transferases in rat liver microsomes determined by immunochemical methods.
The amount and nature of glutathione transferases in rat liver microsomes were determined using immunological techniques. It was shown that cytosolic glutathione transferase subunits A plus C, and B plus L were present at levels of 2.4 +/- 0.6 and 1.5 +/- 0.1 microgram/mg microsomal protein, respectively. These levels are 10-times higher than those for non-specific binding of cytosolic components judging from the distribution of lactate dehydrogenase, a cytosolic marker. The possibility that a portion of these glutathione transferases is functionally localized on the endoplasmic reticulum is discussed. A previously described microsomal glutathione transferase which is distinct from the cytosolic enzymes is present in an amount of 31 +/- 6 micrograms/mg microsomal protein.
Animals↗
Microsomal glutathione transferase. Purification in unactivated form and further characterization of the activation process, substrate specificity and amino acid composition.
The procedure developed for purification of the N-ethylmaleimide-activated microsomal glutathione transferase was applied successfully to isolation of this same enzyme in unactivated form. The microsomal glutathione transferases, the unactivated and activated forms, were shown to be identical in terms of molecular weight, immunochemical properties, and amino acid composition. In addition the microsomal glutathione transferase purified in unactivated form could be activated 15-fold with N-ethylmaleimide to give the same specific activity with 1-chloro-2,4-dinitrobenzene as that observed for the enzyme isolated in activated form. This activation involved the binding of one molecule N-ethylmaleimide to the single cysteine residue present in each polypeptide chain of the enzyme, as shown by amino acid analysis, determination of sulfhydryl groups by 2,2'-dithiopyridyl and binding of radioactive N-ethylmaleimide. Except for the presence of only a single cysteine residue and the total absence of tryptophan, the amino acid composition of the microsomal glutathione transferase is not remarkable. The contents of aspartic acid/asparagine + glutamic acid/glutamine, of basic amino acids, and of hydrophobic amino acids are 15%, 12% and 54% respectively. The isoelectric point of the enzyme is 10.1. Microsomal glutathione transferase conjugates a wide range of substrates with glutathione and also demonstrates glutathione peroxidase activity with cumene hydroperoxide, suggesting that it may be involved in preventing lipid peroxidation. Of the nine substrates identified here, the enzymatic activity towards only two, 1-chloro-2,4-dinitrobenzene and cumene hydroperoxide, could be increased by treatment with N-ethylmaleimide. This treatment results in increases in both the apparent Km values and V values for 1-chloro-2,4-dinitrobenzene and cumene hydroperoxide. Thus, although clearly distinct from the cytosolic glutathione transferases, the microsomal enzyme shares certain properties with these soluble enzymes, including a relative abundance, a high isoelectric point and a broad substrate specificity. The exact role of the microsomal glutathione transferase in drug metabolism, as well as other possible functions, remains to be established.
Amino Acids↗