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.

Alterations induced by lithium in gfap expression and in the proteinic composition of glial cells in vitro.

In the adult brain, astrocytes account for about 40% of the cell population in the central nervous system. Normal, reactive and neoplastic astrocytes can be identified in immunohistochemical preparations by means of glial fibrillary acid proteins (GFAP) expression. This protein is considered to be a sensitive indicator of xenobiotics toxicity. Previous studies have demonstrated that 2 mM LiCl induce alterations of astrocyte morphology after 18-20 days of treatment in vitro. We have decided to study GFAP expression under such conditions. Immunodetection and Western blotting assays have shown 2 mM of LiCl to induce alterations of GFAP expression both after 12 days of treatment and after 18-20 days. Moreover, 2 mM of LiCl induce an alteration of the proteinic composition of cells.

Influence of acceleration over the hydroelectrolytic homeostasis in audiogenic seizure-prone rats compared to normoexcitable rats.

This research concentrated on the hydroelectrolytic balance response after centrifugation (+5G/30 minutes, five times) in two lots of rats: one lot made up of animals with normal cerebral excitability, and another one of animals prone to audiogenic seizure. Both before and after centrifugation, we determined: water (ml/24 hrs.) and sodium chloride (mEq/24 hrs.) consumption; dependence of sodium, potassium and water elimination on the amount of sodium ingested (mEq/24 hrs.). We also determined the renal capacity of sodium concentration and the mineral-corticoid response based on the urine Na/K ratio and on the determination of plasma renin activity (PRA). Data obtained show that audiogenic seizure-prone rats consume less sodium and water after centrifugation, unlike normoexcitable rats in which there have been no differences in this respect. Exposure to hypergravitation induces in both lots an increase of sodium, potassium and water elimination. Renal elimination of water is greater in the normoexcitable animals than in the seizure-prone ones. By contrast, sodium elimination is greater in the audiogenic seizure-prone animals. Urine sodium concentration is lower in the seizure-prone animals, consistent with the amounts of water eliminated. Their mineral-corticoid response is intensely diminished after centrifugation in comparison to that of the control, normo-excitable animals. PRA is diminished in both lots. Our findings support the assumption that seizure-prone rats are unable to adaptatively respond to acceleration by preserving sodium through the intervention of cortico-surrenal mechanisms. As water is not preserved, it seems that in this category of animals, both during and after centrifugation, it is mostly the hypothalamo-retrohypophyseal mechanisms that come into play. This could be the outcome of disturbances occurring in the mechanisms of blood sodium transport that are deficient in the seizure-prone animals.

Influence of lithium on the cellular environment.

In order to study the influence of lithium on the cellular environment, we conducted research in multiple experimental models: groups of rats with normal cerebral excitability and groups susceptible to audiogenic convulsion, rat neuroglia cultures and perfusion of dog isolated head. We assumed blood composition to be a good indicator of cell environment composition. Blood serotonin level differs in the two groups of animals. Lithium induces a decrease of blood serotonin and an increase of amine concentration in some of the cerebral regions of rats susceptible to audiogenic convulsions. Inverse effects occur in rats with normal cerebral excitability. In the perfused, isolated head of a dog, lithium immediately decreases blood serotonin level. Na and water have a diminished metabolization during the first 24 hrs. in both animal groups. Decrease in metabolization is somewhat greater in hyperexcitable animals. Within 48 hrs. after lithium injection, there is an increase of Na metabolization, probably determined by its storage in the interstice. Renal elimination of K decreases under the influence of lithium 48 hrs. after administering one dose of lithium. Lithium induces, immediately after injection, a decrease of blood Na concentration in the efferent flow of the jugular vein of a perfused dog head. When used in cell cultures, lithium (2 mM concentration) stimulates glial cells division (astrocytes, oligodendrocytes), increases their growth and aging rates. The effects of lithium may be due to its toxicity. Therefore, lithium alters the composition of the cellular environment depending on dose and on the state of the body.

Incidence of morphofunctional lesions in the cervical region of patients with gall-bladder dyskinesia.

During research performed in humans of both sexes, aged 17-30, suffering from disorders of gall-bladder kinetics, we found a constant association between this disorder and a cervical syndrome with occipital cephalea, spasmophilia, pre-molar and molar dental decay, even to edentation. We believe the mechanism inducing those disorders originates in the malabsorption of vitamin D2, caused by the absence of biliary salts in the intestine. Our findings could be of interest for the therapeutic management of such cases. In conclusion, we describe a new clinical framework establishing a pathological pattern that is functionally and morphologically coherent. The pattern includes the motor-biliary condition that induces disorders in the mechanism of calcium metabolism control. It also includes major neuromuscle hyperexcitability in the pre-vertebral region associated with the biped posture. Functional and morphological lesions in the cervical region of the spine, with Arnold-type manifestations and spasmophilia prevail in the final clinical picture. This picture is very early associated with multiple dental caries that may progress to edentation. The clinical picture appears as a coherent pattern, from a clinical, morpho-functional and pathogenic perspective.

Effect of combination interleukin-3 (IL-3) and granulocyte-macrophage colony stimulating factor (GM-CSF) on hematopoiesis administered to retrovirus-infected immunodeficient mice receiving dose-escalation zidovudine (AZT).

We have previously demonstrated that continuous administration of dose-escalation zidovudine (AZT) in either normal or LP-BM5 MuLV immunodeficient virus-infected mice (MAIDS) was associated with the development of anemia, neutropenia, and thrombocytopenia. Hematopoietic growth factors/cytokines are being evaluated to determine their efficacy in ameliorating the hematopoietic toxicity associated with AZT. In normal mice receiving AZT, an increase in only plasma erythropoietin and not GM-CSF, Meg-CSF or TNF-alpha has been reported. This article describes studies that investigated the effect of combination interleukin-3 (IL-3) and granulocyte-macrophage colony stimulating factor (GM-CSF) administered in normal non-viral, viral-infected, and viral-infected C57BL6 mice receiving dose-escalation AZT, i.e. 0.1 mg/ml, 1.0 mg/ml, and 2.5 mg/ml placed in the drinking water. Non-viral control mice responded to IL-3/GM-CSF by increasing erythropoiesis, myelopoiesis and platelet production measured by increased bone marrow and spleen derived erythroid, myeloid and platelet precursor stem cells cultured in semi-solid media. Virus-infected control mice not receiving IL-3/GM-CSF developed pancytopenia. Administration of IL-3/GM-CSF to virus-infected mice receiving dose-escalation AZT did not ameliorate the peripheral pancytopenia associated with immunodeficiency disease and AZT treatment, even though erythroid, myeloid and platelet precursor progenitor cells were increased at certain times when compared to either normal or viral-infected mice receiving IL-3/GM-CSF. These results indicate that the combination use of IL-3 and GM-CSF in vivo is only a partially effective growth factor/cytokine treatment to ameliorate the hematopoietic toxicity associated with the use of the anti-viral drug zidovudine.

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.

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.

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.

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.

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.

The influence of malathion on the brain serotonin and reproductive function in rats.

By researches carried out in adult female rats we followed the effect of chronic administration of malathion on the serotonin level from hypothalamus, rhynencephalon, mesencephalon and cerebral cortex and on the hypophysio-ovarian system. The obtained results showed that malathion produces: 1) the increase of cerebral serotonin level through the active phases of the gonadal cycle (proestrus + oestrus); 2) the increase of the percent incidence of the gonadal active phases; 3) the decrease of the LH synthesis through the oestral cycle; 4) the increase of the FSH release during the active phases and the decrease of the LH release in the inactive phases of the ovarian cycle. The data show that malathion influences the reproductive function both by its cellular toxic action and by affecting the encephalic regulatory serotoninergic, besides acetylcholinergic, mechanism of the reproductive functions.

Influence of angiotensin II on dog pineal serotonin content.

Intravenous infusion of angiotensin II in different concentrations for 2 h induced an increase in the serotonin contents of pineal gland, hypothalamus and brain stem in dogs. The maximal stimulatory effect was obtained with a concentration of 50 ng angiotensin II/kg body wt./min. Results are interpreted with regard to the concept of an intrinsic isorenin-angiotensin system and its implications at the level of brain nervous tissue and accessory glands. Experimental data indicating the possible existence of positive and negative feedback relationships between the brain isorenin-angiotensin system and serotonin metabolism in the pineal gland, are presented.

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.

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.

Relationship between bovine serum albumin structure and its chemical equilibria with hydrogen and 5-hydroxytryptamine ions.

From the analysis of titration curves with hydrogen and 5-HT ions, it was found that the electrostatic interaction parameter of protein macroion and the number sites of 5-HT fixing were smaller over an acid and base pH range as compared to their values at neutral pH. Our data were interpreted by the conformational changes which can be induced when BSA is exposed to denaturation by acid and alkali pH.

Determination of blood serum protein reactivity in children with behavior disturbances.

The researches were carried out on two groups of children: normals and with behavior disturbances. The serum cationic state was determined by an original method, using heparin as cautions exchanger in physiological pH, and the protein reactivity; the electrophoretic mobility of serum proteins at pH 7.4; total soduim and serum proteins. The obtained results show that serum proteins in children with behavior disturbances differ from those of normals, having: 1) smaller number of serotonin-fixing sites, 2) higher strength interaction between the serotonin and proteins, 3) lower resistance to the denaturant agents which has as a consequence the increase of cationic activity in the serum, and an increased electrophoretic mobility. The data are discussed and interpreted as perturbations in the electrolytes exchange (Na+, especially) in the integration centres of the autonomic functions.

Serotonin through pregnancy. Comparative researches in different species and in mankind.

By spectrofluorimetric method there was followed the blood and cerebral serotonin content in different species of mammalians: in 28 women, from the venous whole blood collected by cubital puncture, and in 20 cows, from the jugular whole blood. In 90 female rats the serotonin content from hypothalamus, rhinencephalon, mesencephalon, and sensorimotor cortex was determined. The obtained data show that in the course of labour in both species the blood serotonin concentration is decreased, returning to its initial values after delivery. The serotonin concentration in cows is 10--15 times higher than in women. As concerns the serotonin values in the cerebral nuclei through pregnancy, a progressive and significant increase of its content was noted in the hypothalamus, rhinencephalon, and mesencephalon, but not in the cerebral cortex. It reaches its maximum concentration at the end of pregnancy. It was concluded that during pregnancy a reduction of serotonin release processes is produced, which can signify a lower functional level of the serotoninergic structures implied in the regulation of the reproductive functions. The data are interpreted in the light of the particular endocrine state existing through pregnancy, attributing to serotonin a role in the functioning of PIF-prolactin system.