Biomedical subjects

M O Mikhailova

Publications and source records attributed to M O Mikhailova.

4 recordsLinked to original sources

PubMed2003

The effects of motivational and emotional factors in glutamate release in the nucleus accumbens of the rat brain during food consumption.

Studies on male Sprague-Dawley rats using intracerebral dialysis and high-performance liquid chromatography with electrochemical detection showed that consumption of fold with an attractive taste was accompanied by decreases in glutamate levels in the intercelular space of the nucleus accumbens, whose depth and duration depended on food deprivation. It was only in deprived animals that food consumption in conditions of presentation of a conditioned sound signal previously combined with electrocutaneous stimulation of the paws led to increases in intercellular glutamate levels in this structure. Isolated presentation of the aversion-relevant conditioned stimulation did not elicit changes in intercellular glutamate levels. These data suggest cooperativity in the actions of motivational and emotional factors in controlling glutamate release into the intercellular space of the nucleus accumbens during food consumption.

Animals↗

PubMed2003

Comparison of changes in glutamate levels in the nucleus accumbens of the rat brain during food consumption in conditions of blockade of dopamine D1 and D2 receptors.

The effects of blockade of D1 and D2 dopamine receptors in the nucleus accumbens on changes in glutamate levels in the intercellular space of this structure during food consumption were studied in Sprague-Dawley rats by intracerebral microdialysis combined with HPLC. These experiments showed that food consumption was accompanied by decreases in glutamate levels in the intercellular spaces of the nucleus accumbens. Blockade of D1 dopamine receptors with SCH-23390 (0.01 mM) produced no changes in the dynamics of glutamate release during food consumption. Food consumption in conditions of blockade of D2 dopamine receptors with raclopride (0.01 mM) induced increases in glutamate levels. These data suggest that glutamate levels during food consumption are controlled by the dopaminergic system of the nucleus accumbens, mediated by D2 but not D1 dopamine receptors.

Animals↗

PubMed2002

Feeding-induced decrease in extracellular glutamate level in the rat nucleus accumbens: dependence on glutamate uptake.

In vivo microdialysis combined with high-performance liquid chromatography and electrochemical detection was used to monitor extracellular glutamate levels in the medial nucleus accumbens of Sprague-Dawley rats during their feeding behaviour. Consumption of a palatable new diet or a diet to which rats were previously exposed caused a decrease in extracellular level of glutamate in the nucleus accumbens during and after feeding. The presentation of an inedible object (a piece of rubber) instead of the expected food caused a marked increase in extracellular glutamate levels. In contrast, if the piece of rubber was presented to rats that did not expect food delivery, the extracellular level of glutamate remained unchanged during the rubber presentation. The feeding-induced decrease in the extracellular glutamate level did not depend on food deprivation and was completely prevented by intraaccumbal infusions through the dialysis probe of 10 mM D,L-threo-beta-hydroxyaspartate (a glutamate uptake inhibitor). Intraaccumbal infusions of 10 microM S-(-)-raclopride L-tartrate (a D2/D3 dopamine receptor antagonist) or 1 microM tetrodotoxin (a voltage-dependent Na(+) channel blocker) also completely reversed the decrease in extracellular glutamate level in response to food intake. The D1/D5 dopamine receptor antagonist SCH-23390 (10 microM) administered into the nucleus accumbens had no significant effect on the feeding-induced decrease in extracellular glutamate level. From the data obtained we suggest that the decrease in the extracellular level of glutamate in the medial nucleus accumbens in response to feeding appears to arise from a temporal increase in glutamate uptake that is probably operated by dopamine inputs to the nucleus accumbens via D2/D3 receptors. Our findings also suggest that the dissociation between the expected biological value of a presented object and the reality might be an important determinant for regulation of glutamate release in this brain area during feeding behaviour.

Analysis of Variance↗

PubMedDate not supplied

Dopamine-dependent inhibition of glycine release in the nucleus accumbens of the rat brain during food consumption.

Studies of Sprague-Dawley rats using in vivo intracerebral dialysis and high-performance liquid chromatography with electrochemical detection were used to investigate glycine release into the intercellular space of the nucleus accumbens during food consumption. The results showed that food consumption led to decreases in glycine levels in the intercellular space of the nucleus accumbens. Administration of the sodium channel blocker tetrodotoxin (1 microM), but not the glutamate reuptake blocker D,L-threo-hydroxyaspartate (1 mM), prevented the food-related behavior-induced decrease in glycine levels in the nucleus accumbens. Eating of food after administration of the dopamine D2 receptor blocker raclopride (10 microM) into the nucleus accumbens was accompanied by an increase in the glycine level in the intercellular space of this structure. These data provide evidence for the neural regulation of glycine release in the nucleus accumbens during food-related behavior, mediated via dopamine D2 receptors.

Animals↗