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Biomedical subjects

P Plenge

Publications and source records attributed to P Plenge.

70 records · Page 4Linked to original sources
PubMed1981

Serum lithium concentrations around the clock with different treatment regimens and the diurnal variation of the renal lithium clearance.

The serum lithium concentration was determined around the clock in patients treated with conventional tablets given once daily, in the evening, and in patients treated with slow-release tablets given twice daily, in the morning and in the evening. Curve shapes differed markedly in the two groups, with much wider variation of serum concentrations in the former than in the latter. The data were used to calculate for the two patient groups the ratio of the mean serum lithium concentration over the 24-h day to the serum lithium concentration in blood samples drawn 12 h after the last intake of lithium. Around-the-clock determinations of the patients' renal lithium clearance showed about 20% lower values during the night than during the day.

Bipolar Disorder↗
PubMed1978

Lithium effects on rat brain glucose metabolism in long-term lithium-treated rats studied in vivo.

The time course of lithium effects on several brain energy metabolites has been investigated in rats. The rats were injected once daily with lithium chloride and killed by freezing in liquid nitrogen 1--8 h after the last injection. The effect of lithium was most marked in the period in which the brain lithium concentration was increasing, whereas the effect was wearing off when the brain lithium concentration had stabilized, even though the lithium concentration was higher. These results led to the hypothesis that the effect of lithium on several parameters depends on the increase in lithium concentration following the administration of lithium, rather than on the absolute concentration of lithium.

Animals↗
PubMed1976

Lithium effects on serum calcium, magnesium and phosphate, in rats.

LiCl was injected daily to rats in a dose of 3 mmol/kg. The rats were, in different experiments, unoperated rats, parathyroidectomized rats and thyroparathyroidectomized rats. Serum concentrations of calcium, magnesium, and phosphate were measured 2 h after a lithium injection. Serum calcium was unaffected by lithium in unoperated and parathyroidectomized rats. In thyroparathyroidectomized rats lithium increased the serum calcium concentration. Serum magnesium was increased by lithium in all 3 groups of rats. Serum phosphate was slightly decreased by lithium in all 3 groups of rats. It is concluded that lithium increases both serum calcium and magnesium, but in the intact organism only a slight or no increase in serum calcium is seem after lithium due to physiological control mechanisms. After removal of the calcitonin producing C-cells in the thyroid gland the organism is unable to produce a fast decrease in serum calcium, and lithium is then able to increase the serum calcium concentration.

Animals↗
PubMed1976

Acute lithium effects on rat brain glucose metabolism - in vivo.

Administration of LiCl to rats was found to affect brain glucose metabolism in the following ways. The concentrations of brain glucose, brain lactate and brain glycogen were increased, and the concentration of brain glutamate was decreased. The incorporation of (14)C from U-(14)C D-glucose, administered intraperitoneally to the rats, was increased in brain glucose and brain lactate, and decreased in brain glutamate. The results were explained by a lithium-induced increase in brain glucose uptake and an increased rate of glycolysis, and a slight inhibition of the oxidative decarboxylation of the Krebs cycle.

Animals↗
PubMed1976

Lithium effects on magnesium, calcium, and phosphate metabolism in rats.

Rats were treated with lithium chloride for 8 weeks. At the last day of lithium administration, the animals were given radioactive calcium, magnesium, and phosphate. Electrolyte content and radioactivity were determined in serum, bone, muscle, liver and brain. Lithium led to an increase of inorganic phosphate in muscle and a decrease in serum. Uptake of radioactive phosphate was increased in muscle and liver but reduced in bone. The amount of magnesium in muscle and serum was increased in the lithium-treated rats, whereas the uptake of radioactive magnesium into bone was decreased. Uptake of radioactive calcium into bone was reduced, and radioactive calcium in serum was increased after lithium.

Animals↗
PubMedDate not supplied

Effects of white spirits on rat brain 5-HT receptor functions and synaptic remodeling.

Previously, inhalation exposure to different types of white spirit (i.e. complex mixtures of aliphatic, aromatic, alkyl aromatic, and naphthenic hydrocarbons) has been shown to induce neurochemical effects in rat brains. Especially, the serotonergic system was involved at the global, regional, and subcellular levels. This study investigates the effects of two types of white spirit on 5-hydroxytryptamine (5-HT) transporters (5-HTT), 5-HT(2A) and 5-HT(4) receptor expression in forebrain, and on neural cell adhesion molecule (NCAM) and 25-kDa synaptosomal associated protein (SNAP-25) concentrations when applied as indices for synaptic remodeling in forebrain, hippocampus, and entorhinal cortex. Male Wistar rats were exposed to 0, 400, or 800 ppm of aromatic (20 vol.% aromatic hydrocarbons) or dearomatized white spirit (catalytically hydrogenated white spirit) in the inhaled air for 6 h/day, 7 days/week for 3 weeks. The 5-HTT B(max) and K(d) were not affected. Both types of white spirit at 800 ppm decreased B(max) for the 5-HT(2A) receptor. The aromatic type decreased the K(d) of the 5-HT(2A) and 5-HT(4) receptors at 800 ppm. Aromatic white spirit did not affect NCAM or SNAP-25 concentrations or NCAM/SNAP-25 ratio in forebrain, whereas NCAM increased in hippocampus and the NCAM/SNAP-25 ratio decreased in entorhinal cortex. Dearomatized white spirit did not affect NCAM, SNAP-25, or NCAM/SNAP-25 ratio in any brain region. The affected 5-HT receptor expression and synaptic plasticity marker proteins indicate that inhalation exposure to high concentrations of white spirit may be neurotoxic to rats, especially the aromatic white spirit type.

Administration, Inhalation↗