Search PubMed⌕ Search

Biomedical subjects

A Carlsson

Publications and source records attributed to A Carlsson.

At least 325 records · Page 18Linked to original sources
PubMed1981

5-HT reuptake inhibitors plus tryptophan in endogenous depression.

In a previous double-blind, 3-week study we compared the effect of clomipramine + placebo with clomipramine + tryptophan in 24 patients with endogenous depression. The patients in the latter group showed a significantly more rapid improvement than those in the former group, especially with regard to the depression-anxiety cluster of symptoms. These results prompted us to perform a similar study in which zimelidine, a more specific inhibitor of 5-HT reuptake, was used instead of clomipramine. In other respects the design was practically identical to that used in the previous study. Unexpectedly, tryptophan in combination with zimelidine, was not superior to placebo + zimelidine with respect to antidepressant activity. In comparison with the previous study, the antidepressant action of zimelidine showed no statistically significant difference from clomipramine. However, the patients tended to show a more prompt response after zimelidine + placebo than after clomipramine + placebo. The changes in CSF metabolites were likewise different in the two studies. In the two studies taken together 12 out of 49 patients showed prompt improvement within one week. This raises the question whether the therapeutic response to antidepressant drugs necessarily involves a delay as is generally assumed. Side effects were remarkably few and mild in the second study.

Biogenic Amines↗
PubMed1981

Distribution and elimination of 14C-xylene in rat.

Male rats were exposed to about 45 ppm of radioactively labeled xylene in the inspired air for 1--8 h. The distribution and elimination of xylene and metabolites in different organs and tissues were studied. To get an idea of the ratio between unmetabolized and metabolized xylene in organs and tissues, a supplementary study was performed in which five male rats were exposed to about 250 ppm of radioactively labeled xylene. The concentration of xylene and metabolites in the subcutaneous fat, where the largest amounts were found, displayed a sharp rise during the first 4 h of exposure in comparison with the following 4 h. Both during exposure and the decay phase the concentration of xylene and its metabolites in the cerebrum, cerebellum and muscles paralleled the arterial blood concentration and amounted to about 40% of the arterial blood value for xylene. The coefficient between the concentration of unmetabolized xylene in subcutaneous fat and inspiratory air was calculated to be 525 after 8 h of exposure.

Animals↗
PubMed1981

Distribution and elimination of 14C-styrene in rat.

Male rats were exposed to about 45 ppm of radioactively labeled styrene in the inspired air for 1--8 h. The distribution and elimination of styrene and its metabolites in different organs and tissues were studied. To get an idea of the ratio between unmetabolized and metabolized styrene in organs and tissues, a supplementary study was performed in which five male rats were exposed to about 250 ppm of radioactively labeled styrene. The largest amounts of styrene and its metabolites were found in the subcutaneous fat, and the concentration displayed a sharp rise during the first 4 h of exposure in comparison with the following 4 h. The concentration of styrene and its metabolites in the cerebrum, cerebellum and muscles paralleled the arterial blood concentration throughout the entire period of exposure and amounted to about 70% of the arterial blood value. In the supplementary study an accumulation of styrene metabolites in subcutaneous fat was disclosed; it ranged from 15 to 20% during exposure.

Animals↗
PubMed1980

Ethanol-induced increase in brain concentrations of administered neutral amino acids.

Ethanol 2 g kg-1 i.p. to rat increased the concentrations in the brain of administered large neutral amino acids (tyrosine, tryptophan, 5-hydroxytryptophan and alpha-methyldopa). We have previously found a similar effect of ethanol on administered L-Dopa, resulting in increased brain/plasma ratios of dopa. Since large neutral amino acids are known to complete with each other for the carrier-mediated transport into the brain we suggest that the increased concentrations of the administered amino acids in the brain are at least partly the consequence of the ethanol-induced decrease in plasma amino acids observed previously.

Amino Acids↗
PubMed1979

Opposite effects of naloxone on substance P-induced changes in brain DOPA synthesis and in locomotor activity in rats.

Intracerebroventricular injection of substance P (SP) enhanced the synthesis of dopamine and noradrenaline (measured as increase in DOPA formation after inhibition of the aromatic L-amino-acid decarboxylase) in rat brain. These biochemical effects were blocked in most brain regions by pretreatment with naloxone. SP also induced vasodilation, salivation and increased locomotor activity. These effects were not antagonized, but, in the case of locomotor activity, potentiated by naloxone. The data suggest the existence of specific SP-containing neuronal pathways for behavior, which pathways are not related to those regulating the synthesis of brain catecholamines.

Animals↗
PubMed1979

Effects of gonadectomy and hormone replacement on brain monoamine synthesis in male rats.

The synthesis of catecholamines and serotonin in the brains of castrated male rats was analyzed at either various times after castration or at various ages. It was found that (a) castration of rats at 50 days or later causes an increase in brain monoamine synthesis, and (b) this phenomenon was not observed until 20 days after castration. The increase in brain monoamine synthesis following castration was counteracted by treatment with testosterone, thus relating the biochemical consequences of castration with changed hormonal conditions of the animal. It is suggested that testosterone exerts an inhibitory influence on monoamine synthesis.

5-Hydroxytryptophan↗
PubMed1979

N-Alkylated 2-aminotetralins: central dopamine-receptor stimulating activity.

In order to define the structural requirements of N-substituents of 2-aminotetralins as central dopamine receptor agonists, a series of N-alkyl- and N,N-dialkyl-substituted 2-amino-5-hydroxy- and 2-amino-5-methoxytetralins have been synthesized and evaluated. The compounds were tested biochemically and behaviorally for dopaminergic activity. From the biochemical data it is concluded that an n-propyl group on the nitrogen is optimal for activity. The corresponding N-ethyl-substituted compounds are slightly less active, while the absence of N-ethyl or N-propyl groups give almost inactive compounds. It could be demonstrated that this is due to steric and not to lipophilic factors. It is suggested that a possible requirement for a potent agonist is that one of it N substituents must fit into a receptor cavity which, because of its size, can maximally accommodate an n-propyl but also smaller groups like ethyl or methyl. The active compounds appeared to give a similar relative pre- and postsynaptic stimulation and had also similar activities for the limbic system and for striatum. None of the compounds listed seemed to have central noradrenaline- or serotonin-receptor stimulating activity.

5-Hydroxytryptophan↗