Search PubMed⌕ Search

Biomedical subjects

M Uluitu

Publications and source records attributed to M Uluitu.

34 records · Page 2Linked to original sources
PubMedDate not supplied

Cerebral excitability and the mechanisms of blood transportation of sodium.

The basic, fundamental property of living structures is excitability. This process defines how an organism responds to both internal and external stimuli. Previous studies have indicated the existence of physical and chemical interactions between cations and anions sites of proteins within the extracellular environment that have a specific functional importance. However, it is not well understood whether specific cations may alter the function of specific proteins. We report here the results of studies that indicate interaction of specific cations such as sodium may alter the physico-chemical action of heparin. The importance of these interactions is discussed.

Animals↗
PubMedDate not supplied

The influence of auditory and lithium stimulation on blood and brain serotonin in the normal rat and in that susceptible to audiogenic convulsions.

Investigations were carried out in two groups of male rats: a group susceptible to audiogenic convulsions and a control group. The following parameters were determined under basal conditions and 24 and 48 hours after intraperitoneal administration of a single lithium carbonate dose (0.67 mEq/animal), before and after auditory stimulation: serotonin content in the blood and brain tissue (separately from the hypothalamus, rhinencephalon, midbrain and sensory-motor cerebral cortex) by fluorimetry: water-saline retention, renal potassium elimination, the dynamics of renal lithium elimination. The results showed that in the rats prone to audiogenic convulsions, blood serotonin concentrations are twice those in the controls, whereas serotonin levels in the brain are lower than in the controls. The administration of lithium is followed by a decrease in blood serotonin in the animals with audiogenic convulsions but does not influence the serotonin content in the brain. Acoustic stimulation does not influence the behaviour of the controls but induces convulsions in the animals sensitive to noise. After auditory stimulation under basal conditions or 48 hours after the administration of lithium a decrease takes place in cerebral serotonin and an increase in blood serotonin in the controls whereas in the rats sensitive to noise, cerebral serotonin increases and blood serotonin decreases on stimulation under basal conditions due to the convulsions and metabolic alterations induced by the latter. These findings suggest the existence of different mechanisms for the transport of serotonin in the blood of rats prone to audiogenic convulsions. These mechanisms may be influenced either by acid catabolites resulting from convulsive activity or by the administration of lithium. The latter may induce persistent alterations in the blood transporter, as appears to result from the observation at 48 hours after the administration of lithium.

Acoustic Stimulation↗
PubMedDate not supplied

EEG automatic processing method.

This is a description of researches carried out in man and experimentally in rats. The results - obtained in 44 children aged between 12 and 14 yr. - of the electric signal processed as a F/A ratio were compared to the transport mechanisms of the blood sodium. We found that the normal brain excitability level was consistent only with the blood sodium transport through interaction with the proteins. The lack of such interaction was accompanied by an increased excitability on eeg recordings and by behaviour disturbances. The researches carried out in rats had in view the brain excitability level in two groups of animals aged 6-8 months, which drank from their birth either physiological salt (group 1) or distilled water (group 2). In this species, in spite of direct visible modifications in eeg recordings by sensorial stimulation, the processing as F/A ratio did not show any differences, and this made necessary the use of computers to process rightly the data; the respective digitization and memorising methods are described, too.

Adolescent↗
PubMedDate not supplied

The serotonin and prolactin content of the blood in women with idiopathic galactorrhoea.

In two groups of women--one group of 12 normal-mammary-gland controls and another group of 10 idiopathic galactorrhoea patients--we determined the blood concentration of serotonin and prolactin. The obtained data show no significant differences between the studied groups either in serotonin or prolactin levels i.e., serotonin is not implied in the pathogeny of idiopathic galactorrhoea. The data are confirming our previous results concerning the functional correlations between the serotonin system and prolactin release, as well as the data obtained by other authors on the normal values of prolactin in idiopathic galactorrhoea.

Adolescent↗
PubMedDate not supplied

Pattern of the cerebrospinal fluid (CSF) and blood biogenic amines and of the CSF, blood and urine amino acids as pathogenetic ground of the senile depressive illness.

A lot of over 60 atherosclerotics with clinical manifestations of senile depressive illness was studied comparatively with a lot of subjects of the same age with essential arterial hypertension (EAH). As concerns the behaviour of the catecholamine content in CSF and blood, the total catecholamines are approxiately equal in the two lots, but with a clear difference of the catecholamine fractions. The CSF catecholamines behaviour in old atherosclerotics is characterized by the presence of increased values of noradrenaline (NA) and of adrenaline (A), with increased statistical significance, but without modifications of the adrenaline percentage (A %) from the total catecholamines, comparatively to the values found in normal subjects. The serotonin (5-HT) content of the CSF in men with atherosclerotic senile depressive illness was lower even than in subjects with coronary atherosclerosis. In atherosclerosis protides modifications precede the histologic changes. In CSF, GLU, ALA, TYR increase in old subjects. In blood, GLU, ALA, TYR, HIS, LEU, SER increase in the same subjects. ARG decreases with age. THR is higher in men than in women. In the urine of all the men as well as of all the women of more than 60 years, GLN and ALA have increased values. LYS increases with age. GLN and ARG are higher in men than in women.

Aged↗
PubMedDate not supplied

On some electrolytic and water metabolism modifications in rats susceptible to audiogenic convulsions.

Following our research in the relationship between mechanisms of blood transportation of sodium and cerebral excitability, we studied adult rats (males-180-230 gm), divided into two groups according to their level of excitability to noise: 1. Rats susceptible to audiogenic convulsions and, 2. Rats with normal response to acoustic stimulation. In the two groups we determined the following parameters: 1. mechanisms of blood transportation of sodium; 2. general free motor behaviour; oriented behaviour (to satisfy motivation for sodium or water); nature and intensity of motivation expressed as milliliters of liquid and grams of sodium consumed; 3. influence of the variable sodium intake on the renal elimination of sodium, potassium and water. Also the influence of the variable water intake on the renal elimination of water. Results obtained show that: cerebral hyperexcitability manifested as susceptibility to audiogenic convulsions is associated with several modifications expressed as follows: 1) Sodium transportation in blood serum occurs in a free state in rats susceptible to audiogenic convulsions, while in normal rats it occurs in a state of interaction with serum proteins; 2) In animals susceptible to audiogenic convulsions one can notice significant hypermotricity in the behaviour cage; 3) Hyperexcitable animals consume significantly more sodium chloride solution which they freely choose, in a motivational manner, than animals with a normal excitability; 4) Increased, motivational consumption of sodium chloride is associated with increased renal elimination of sodium in animals susceptible to audiogenic convulsions. Increased renal elimination of sodium is accompanied by increased elimination of water, therefore with the protection of renal concentration mechanisms; 5) If we take the Na/K ratio as an indicator for the function of the corticosuprarenal and represent it as a function of the sodium intake, the data presented show that ratio is greater in animals with cerebral hyperexcitability, which is in concordance with the data presented, also involving the mineralcorticoid hormones in this response, a similar picture to that of loading the body with sodium; 6) The data presented seem to advocate once more for the idea that normal cerebral excitability is compatible with the existence of mechanisms that transport sodium in a state of oligoenergetic interaction with blood proteins.

Acoustic Stimulation↗
PubMedDate not supplied

The influence of bufotenin on the feeding behavior and cerebral serotonin content in rats.

By researches carried out in male adult rats (Wistar), the influence of the intraperitoneally injected bufotenin (5 mg/kg b.w. active substance in saline solution) was followed on: I--feeding behavior; II--the serotonin concentration in hypothalamus, rhinencephalon, mesencephalon and sensorimotor cerebral cortex. The obtained results show that bufotenin influences the feeding behavior by reducing the motor functions. Its action depends on the physiological state of the animal: by increasing the alimentary motivation the rats can escape the bufotenin influence, showing a normal behavior; bufotenin does not influence the sensorials, the natural dispositions and the excitability level of the feeding and satiety hypothalamic centers. Bufotenin increases serotonin concentration only in the mesencephalic region, but not in the other studied regions. The results are interpreted as a primary bufotenin action on the serotoninic vasoconstrictive receptors at the mesencephalic level, thus disturbing the serotonin-releasing processes and possibly other chemical neurotransmitters.

Animals↗
PubMedDate not supplied

Influence of increased sodium intake on cerebral excitability.

The purpose of the study has been to observe the influence of an increased dietary sodium intake over cerebral excitability in rats. Research was conducted on two lots of animals: the first lot (PSA) was maintained under the influence of an increased intake of sodium given in the form of physiologic solution, instead of water. That regimen was started during gestation and continued after birth for another 12-14 months before the rats were sacrified. The second lot was given distilled water (DWA) in an identical manner. In other respects, the diet was similar for both lots We compared the following parameters: a) Electrophysiological (electrocorticogram); b) Hydroelectrolytic balance; c) Sodium concentration capacity of the kidney; d) Mineral-corticoid response; e) Motor and motivational behaviour. The data we obtained point to: 1. A shifting of the ECG frequency spectrum towards higher frequency in rats that consumed NaCl in excess. 2. PSA consume significantly more saline solution than DWA, therefore liquid consumption is also greater. Renal elimination of water, Na and K is significantly greater is PSA compared to DWA. Moreover, DWA conserve sodium while PSA conserve water, the respective values being different in a considerable degree in the two lots. 3. The value of the (urinary Na/urinary K) ratio is double in PSA compared to DWA, pointing to a decrease in mineral-corticoid secretion. 5. The animals that have chronically consumed a hypersaline diet show a significantly greater motor agitation compared to the DWA. When free to choose from among physiological solution, water and glucose solution, PSA show no preference for sodium: this points to the absence of obtained motivation for the saline solution The data support the idea that a chronically increased content of dietary NaCl stimulates cerebral excitability.

Animals↗