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Biomedical subjects

D Mück-Seler

Publications and source records attributed to D Mück-Seler.

26 records · Page 2Linked to original sources
PubMed1991

Platelet serotonin in subtypes of schizophrenia and unipolar depression.

In subtypes of schizophrenia and unipolar depression, both increased and decreased levels of platelet serotonin were found. Hyperserotonemia was usually observed in patients with psychotic features (i.e., in paranoid schizophrenia and psychotic depression). Hyposerotonemia, although less common than hyperserotonemia, was present in nonparanoid schizophrenia and nonpsychotic depression (i.e., in patients without psychotic symptoms). A sex difference in platelet monoamine oxidase activity was observed among healthy subjects, but not among schizophrenic patients. The activity of platelet monoamine oxidase in paranoid and nonparanoid schizophrenic patients did not differ from that in healthy subjects. The findings in this study suggest that biological differences between subtypes of unipolar depression or schizophrenia might depend upon the presence of psychotic symptoms.

Adult↗
PubMed1990

Do imipramine and dihydroergosine possess two components--one stimulating 5-HT1 and the other inhibiting 5-HT2 receptors?

The mechanisms by which imipramine and dihydroergosine stimulate the 5-HT syndrome in rats and inhibit the head-twitch response in rats and mice were studied. Imipramine- and dihydroergosine-induced stimulation of the 5-HT syndrome was inhibited stereoselectively by propranolol, a high affinity ligand for 5-HT1 receptor sites, but not by ritanserin, a specific 5-HT2 receptor antagonist. (-)-Propranolol potentiated the inhibitory effect of imipramine, but not of dihydroergosine on the head-twitch response, while ritanserin was without effect. Neither imipramine nor dihydroergosine were able to stimulate the 5-HT syndrome in the animals pretreated with p-chlorophenylalanine. As expected, 8-OH-DPAT, a selective 5-HT1A receptor agonist, stimulated, and 5-HT1B agonists CGS 12066B and 1-(trifluoromethylphenyl)piperazine (TFMPP) failed to stimulate the 5-HT syndrome induced in rats by pargyline and 5-HTP administration. A higher dose of ritanserin inhibited the syndrome. While 8-OH-DPAT alone produced all behavioral components of the 5-HT syndrome, dihydroergosine or imipramine alone even at very high doses never produced tremor or a more intensive forepaw padding as seen when these drugs were given in combination with pargyline and 5-HTP. A single administration of (-)-propranolol also inhibited the head-twitch response. This effect lasted in mice longer than after ritanserin administration. In in vitro experiments dihydroergosine expressed approximately twenty-fold higher affinity for 3H-ketanserin binding sites than imipramine. The results suggest that imipramine and dihydroergosine possess two components--one stimulating the 5-HT syndrome in rats by a presynaptic, presumably 5-HT1A-mediated mechanism, and the other inhibiting 5-HT2 binding sites.

Animals↗
PubMed1989

Inhibitory influence of dihydroergosine on the aggressiveness of rats and mice.

Fifty mg/kg of ergot alkaloid dihydroergosine (DHESN) inhibited the mouse-killing behavior of isolated male rats, while 10 mg/kg did not. This effect of DHESN (50 mg/kg) lasted for 24 hr. When an additional injection of DHESN (50 mg/kg) was given to mouse-killer rats 6 days following the first, the mouse-killing behavior was again inhibited. The effect of the second drug injection also persisted for 24 hr and was accompanied by an increased concentration of 5-HT in the raphe nuclei and hypothalamus and by a decreased concentration of GABA in the olfactory bulbs. DHESN also inhibited aggressiveness in isolated mice. Two hr following the administration of 10 mg/kg DHESN the fighting was inhibited in 46% of pairs tested, while 50 mg/kg abolished it completely. The effect of 50 mg/kg lasted 24 hr. These results, showing the antiaggressive effects of DHESN, support our previous suggestion that DHESN might presumably be a new antidepressant, and suggest that besides the serotoninergic, the GABA-ergic system might also be involved in the modification of behavior induced by this drug.

Aggression↗
PubMed1988

Time course of schizophrenia and platelet 5-HT level.

The concentration of platelet serotonin (5-HT) and the simultaneous uptake of 5-HT into platelets have been investigated in schizophrenic patients with (A) intermittent time course of illness (complete remission), (B) chronic time course (partial remission and residual symptoms), and (C) intermittent-chronic time course (good remission at the beginning of illness with gradual progression to chronic stage). An increased platelet 5-HT concentration (i.e., hyperserotoninemia) of unknown etiology was observed, especially in the group with chronic time course of disease as compared to the normal controls. At the same time, kinetic constants Km and Vmax of 5-HT uptake into platelets were unchanged in all patients. Neuroleptic treatment did not produce any significant change either in platelet 5-HT level or in the uptake of 5-HT. These results provide further support for the possible 5-HT dysfunction in schizophrenia.

Adolescent↗
PubMed1983

Maprotiline in the treatment of endogenous depression: comparison of therapeutic effect with serotonin level in blood platelets.

In blood platelets of untreated patients with endogenous depression a significantly lower concentration of serotonin (5-HT) was found than in healthy persons (P less than 0.05). The patients were afterwards divided into two groups: group I with mild symptoms of depression (total scores by Hamilton Depression Rating Scale below 40) and group II with severe depression (total scores above 40). The gradual diminishing of symptoms in both groups was accompanied by no change in 5-HT level in the first group and by progressive and well marked increases in platelet 5-HT content in the second one, attaining average normal values at the end of week 3 of treatment with maprotiline. In in vitro experiments maprotiline inhibited the uptake of 5-HT into blood platelets of healthy persons less than doxepin. After injection of maprotiline in rats (50 mg/kg IP) the turnover rate of 5-HT in the brain was only marginally affected if measured by 5-HT rise and 5-hydroxyindoleacetic acid (5-HIAA) decline after administration of the MAO inhibitor pargyline, or by estimation of 5-HIAA increase after blocking active transport with probenecid. However, after treatment with maprotiline alone, the 5-HIAA level in the rat brain was significantly increased, although the concentration of 5-HT was not altered. These results suggest: a) the possibility of an action of maprotiline on serotoninergic neurons and b) the suitability of blood platelets as a model for such an investigation.

Adult↗