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At least 523 records · Page 29Linked to original sources
PubMed2004

Microdialysis of the brain structures: application in behavioral research on vasopressin and oxytocin.

In vivo microdialysis allows sampling of brain regions in conscious, freely moving animals. Moreover, the in vivo microdialysis allows to administer drugs directly into specific brain areas. Both are useful in behavioral studies. The subject of this review is the methodology of brain microdialysis, that is construction of the probe, effect of temperature, composition of the perfusion medium, perfusion flow rate, characteristics of the membrane material and the role of the diffusion coefficient. Other techniques of the study of in vivo release, alternative for microdialysis, are described. Advantages and disadvantages of acute and chronic microdialysis are discussed. Chronic microdialysis is especially needed in behavioral studies. Finally, the examples of application of microdialysis in behavioral studies of vasopressin (AVP) and oxytocin (OXT) and our own experience in these studies are described.

Animals↗
PubMedDate not supplied

[Catecholamine levels and tyrosine hydroxylase activity in the brain structures of male mice with a determined behavioral type in a population].

Biosynthetic activity in brain catecholaminergic neurons was studied in male mice with genetically determined dominant (PT strain) and subordinate (CBA) behaviour. The dominant PT mice were characterized by higher levels of catecholamines and tyrosine hydroxylase activity in most of the brain regions in comparison with subordinate CBA mice. Percent of animals with dominant type of behaviour was high among the hybrid F1 males derived from PT and CBA mice. These offsprings inherited also the high levels of noradrenaline and dopamine as well as the high tyrosine hydroxylase activity in the striatum and the brain stem. The obtained data suggest that the level of biosynthetic activity in the brain catecholaminergic neurons is essential for coordination of the brain neurochemical systems in expression of the dominant male mice behaviour in a population.

Animals↗
PubMed2002

Hypnosis modulates activity in brain structures involved in the regulation of consciousness.

The notion of consciousness is at the core of an ongoing debate on the existence and nature of hypnotic states. Previously, we have described changes in brain activity associated with hypnosis (Rainville, Hofbauer, Paus, Duncan, Bushnell, & Price, 1999). Here, we replicate and extend those findings using positron emission tomography (PET) in 10 normal volunteers. Immediately after each of 8 PET scans performed before (4 scans) and after (4 scans) the induction of hypnosis, subjects rated their perceived level of "mental relaxation" and "mental absorption," two of the key dimensions describing the experience of being hypnotized. Regression analyses between regional cerebral blood flow (rCBF) and self-ratings confirm the hypothesized involvement of the anterior cingulate cortex (ACC), the thalamus, and the ponto-mesencephalic brainstem in the production of hypnotic states. Hypnotic relaxation further involved an increase in occipital rCBF that is consistent with our previous interpretation that hypnotic states are characterized by a decrease in cortical arousal and a reduction in cross-modality suppression (disinhibition). In contrast, increases in mental absorption during hypnosis were associated with rCBF increases in a distributed network of cortical and subcortical structures previously described as the brain's attentional system. These findings are discussed in support of a state theory of hypnosis in which the basic changes in phenomenal experience produced by hypnotic induction reflect, at least in part, the modulation of activity within brain areas critically involved in the regulation of consciousness.

Analysis of Variance↗
PubMed1975

[The effect of several psychotropic substances on brain structure].

The authors have shown similarities of structural changes in the neuron and interneuronal relations found in the brains of rats under indopan and LSD stimulation of the CNS with certain differences in the localization of the changes in the functionally different brain systems. A high sensitivity of the sensory-motor cortex and the subcortical formations of the brain, rich in dopamine and serotonin, to indopan has been marked. LSD central effects were conditioned by the influence of the drug not only on the synapsis, but on the cell body components of the different brain systems, especially in the visual. The observed changes were allocated to categories of functional disturbances.

Animals↗
PubMed1984

Comparison of two methods for estimating the acetylcholine turnover in discrete rat brain structures.

The acetylcholine turnover rate was determined in olfactory tubercle, nucleus accumbens and striatum of rat brain. The calculation of turnover rates was carried out by means of two different methods: a two compartment analysis and the finite differences method. After pulse injection of [3H]choline the radioactivity of both [3H]acetylcholine and [3H]choline was measured in the above mentioned brain areas. The contents of acetylcholine and choline were measured radioenzymatically. By using the two compartment model the following acetylcholine turnover rates were obtained: olfactory tubercle, 0.577; nucleus accumbens, 0.679; striatum, 1.110 (mumoles/g X hr). When using the finite differences method the values were: olfactory tubercle, 0.517; nucleus accumbens, 0.822; striatum, 1.115 (mumoles/g X hr). This demonstrates that the results obtained by applying the two different methods are nearly identical. Advantages and disadvantages of the two methods are discussed.

Acetylcholine↗
PubMed1974

[Relationship between thromboplastin activity in different brain structures and the quantitative interrelationships of functionally different groups of phospholipids in them].

The microsomal fraction of rabbit brain has the highest content of phospholipids and is completely devoid of polyglycerophospholipids. The decrease of the ratio of neutral to acid phospholipids is accompanied by a corresponding reduction of thromboplastic activity. Thromboplastic activity is high in the nuclear fraction of the medulla oblongata, cerebellum and cerebral hemispheres. Adrenaline reduces the amount of both total and individual phospholipids (mainly neutral) in subcellular particles of brain. This is accompanied by reduction of thromboplastic activity. The incubation of homogenates of brain parts for 2 hrs in the presence of glucose brings to the increase of phospholipids in the incubation medium and enhancement of thromboplastic activity.

Animals↗