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Biomedical subjects

A A Lebedev

Publications and source records attributed to A A Lebedev.

At least 109 records · Page 6Linked to original sources
PubMedDate not supplied

Comparison of the effects of dopamine agonists on self-stimulation of the hypothalamus with lesioning of mesolimbic brain structures in rats reared in conditions of social isolation.

Initial and phenamine-stimulated frequencies of self-stimulation of the lateral hypothalamus were not significantly different in rats reared in communities and in conditions of social isolation. Unilateral lesioning of the ventral tegmental area and the medial prefrontal cortex in early ontogenesis increased phenamine sensitivity only in isolated rats. The dopamine receptor agonist apomorphine, at a dose of 0.05 mg/kg, which affects presynaptic receptors, inhibited the self-stimulation response in intact group-reared animals and in rats reared in isolation, by 21-23%. Stimulation of the ventral tegmental area did not change, while stimulation of the medial prefrontal cortex doubled the sensitivity of rats to apomorphine in animals reared in isolation (at doses of 0.05 and 0.5 mg/kg). Conditions of partial sensory and complete species isolation resulted in the development of a state of presynaptic receptor hypersensitivity of dopamine receptors in mesocorticolimbic brain systems in rats.

Amphetamine↗
PubMedDate not supplied

[Analysis of various components of the mechanism of stimulation of transepithelial sodium transport by catecholamines].

A study was made of the influence of adrenaline of certain components of the transepithelial sodium transport system in the frog skin an on energy sources providing its activating effect. Adrenaline proved to increase the sodium transport through the frog skin decreasing its electrical resistance. Strophanthin K prevented the reaction of frog skin adrenaline completely. Monoiodacetate also produced an inhibitory action on the adrenaline effect which was eliminated on addition of pyruvate into the solution. Potassium cyanide and 2,4-dinitrophenol considerably weakened the adrenaline stimulation of transepithelial sodium transport. A conclusion was drawn that an increase of sodiun transport by the frog skin in the action of catecholamines was associated with increase of its ionic permeability and the activation of the ionic pump. It is supposed that the principal source of energy provision for the stimulating effect of catecholamines were processes of aerobic energy metabolism.

Animals↗
PubMedDate not supplied

[Effect of the melanostatin analogue alaptide on dopamine-dependent behavior in rats reared in isolation].

The effects of alaptide, a new analog of melanostatine, on self-stimulation of the lateral hypothalamus, rotation behavior in rotometer, and stereotypy were studied in rats bred in social isolation from other animals beginning from the 17th day of birth and rats bred in groups. Alaptide potentiated amphetamine-stimulated behavior only in rats reared in social isolation. This effect was lateralized: the left rotation dominated. In rats reared in isolation and in groups the effects of alaptide on self-stimulation were oppositely directed: in the former it increased and in the latter decreased the rate of self-stimulations with oppositely directed changes in pedal pressing duration. At the same time, alaptide suppressed the effects of amphetamine on self-stimulation of rats reared in isolation. The central dopamine mechanisms of melanostatine action are discussed.

Animals↗
PubMedDate not supplied

[Calcified giant aneurysm of the middle cerebral artery].

A rare case of calcified giant aneurysm of the middle cerebral artery is presented. This is a 28-year-old female with seizures and right-sided hemiparesis in whom plain scull films and computed tomography revealed a large calcified lesion (measuring 7.5 x 5.5 x 4.5 cm) of the left cerebral hemisphere. The lesion was removed by the pterional transsylvian approach and found to be a calcified giant thrombotic aneurysm of the middle cerebral artery. The CT characteristics of these rare lesions and the success of surgery in this case are briefly discussed.

Adult↗
PubMedDate not supplied

[Effect of substance P on ethanol consumption in subchronically alcoholized rats in the limited scheduled access paradigm].

The effect of substance P on alcohol intake was studied in rats using a limited scheduled access paradigm. Ascending doses of substance P (100 and 200 micrograms/kg) were administered intraperitoneally to rats approximately 30 minute prior to their 1-hour-per-day access to alcohol. Each dose was administered for 3 successive days, and the effect of substance P was compared to that of saline solution control. Substance P at the dose of 100 micrograms/kg had no effect on alcohol consumption but significantly decreased the alcohol intake at the dose of 200 micrograms/kg. Thus, substance P reduces the alcohol motivation of rats in a limited scheduled access paradigm.

Alcohol Drinking↗