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J J Meisch

Publications and source records attributed to J J Meisch.

8 recordsLinked to original sources
PubMed1977

Metabolism of 5-hydroxytryptamine and levels of tricyclic antidepressant drugs in rat brain after acute and chronic treatment.

Because tricyclic antidepressants (TAD) are usually given chronically to patients, both their acute and their chronic effects on 5-hydroxytryptamine (5-HT) metabolism were studied. The probenecid method was used and, in addition to 5-hydroxy-indoleacetic acid (5-HIAA), some other indole compounds in brain were measured. Simultaneously, TAD levels in brain and plasma were determined. Dimethylated as well as monomethylated TADs were administered, both at 10 and 25 mg/kg i.p. Treatment with either 10 mg/kg during 14 days or 25 mg/kg given acutely resulted in a similar brain level of TAD, so any differences found could be attributed to differences in administration schedule. Drug levels in brain and plasma differed considerably after chronic and acute treatments but no major differences in the effect on 5-HIAA level in the brain were found, although accumulation of 5-HIAA following probenecid treatment was mostly lowered after treatment with dimethylated TAD. The TAD level in rat brain was not decisive for the effect on central 5-HT turnover. The monomethylated TAD affected the 5-HT turnover very little, not only acutely but also chronically.

Animals↗
PubMed1975

Uptake and disappearance of 4-methyl-alpha-ethylmetatyramine in relation to its releasing action on 5-hydroxytryptamine in the brain.

4-Methyl-alpha-ethylmetatyramine (H75/12) was given intraperitoneally to mice and rats. At various time intervals the animals were killed and the concentration of H75/12 and 5-hydroxytryptamine (5-HT) in the brain and of H75/12 in the heart and, in some cases, in plasma was determined. H75/12 was rapidly taken up by the heart and then disappeared bi- or multiphasically. A maximum concentration of about 6 mug/g was obtained in the brain 30--60 min after the administration of 25 mg/kg. H75/12 disappeared from the brain with a half-life of 1.0 and 1.5 hrs in the mouse and rat, respectively. In the mouse the relative uptake of H75/12 increased with the dose given, i.e. the dose-uptake curve had an upward bending. Significant release of 5-HT in the brain was obtained after a single injection of 25 and 100 mg/kg in the rat and mouse, respectively. The 5-HT release was prevented by tricyclic, antidepressive agents, particularly by chlorimipramine. However, these agents had no certain effect of the uptake of H75/12 in the brain. Moreover, it was not possible to demonstrate a decreased uptake of H75/12 in the rat brain after a chronic, transverse cerebral hemisection, although the monoamine-containing neurones had degenerated as indicated by a complete disappearance of 5-HT. It is concluded that only a minor part of the H75/12 measured is located in monoaminergic neurones. The uptake of H75/12 in the rat brain appeared to be increased in starving animals, possibly indicating decreased metabolism of the drug.

Animals↗