Effects of centrophenoxine on the monovalent electrolyte contents of the large brain cortical cells of old rats

Behavioral alterations in rotenone model of Parkinson's disease: attenuation by co-treatment of centrophenoxine

Rotenone, a potent specific inhibitor of mitochondrial complex-1, appears to reproduce the behavioral features of Parkinson's disease in rats. It destroys dopaminergic neurons selectively, causing deficiency of dopamine in striatum which leads to impaired motor functions. Oxidative stress generated as a result of mitochondrial dysfunction and metabolism of dopamine has been implicated as an important factor in the etiology of Parkinson's disease. Present study explores the potential of centrophenoxine (a well known anti-aging and antioxidant drug) against rotenone induced motor dysfunction. Sprague Dawley male rats were administered with rotenone on a daily basis by subcutaneous injection of dose: 2 mg/kg body weight over a period of 35 days. Data showed impaired motor function, significant increase in catalepsy, decrease in locomotor activity and decrease in muscle activity. Dopamine content of rotenone treated animals was found to decrease significantly and lipid peroxidation was found to increase significantly in rotenone treated animals when compared with co-treated group. Co-treatment with centrophenoxine (100 mg/kg i.p. for 35 days) significantly attenuated the extent of motor dysfunction and changes in the level of dopamine and lipid peroxidation induced by rotenone toxicity. Thus, the present study provides evidence that centrophenoxine co-treatment attenuates rotenone induced motor dysfunction by virtue of its antioxidant action.

Evidence for centrophenoxine as a protective drug in aluminium induced behavioral and biochemical alteration in rat brain

Potential use of various nootropic drugs have been a burning area of research on account of various physical and chemical insult in brain under different toxicological conditions. One of the nootropic drug centrophenoxine, also known as an anti-aging drug has been exploited in the present experiment under aluminium toxic conditions. Aluminium was administered by oral gavage at a dose level of 100 mg/Kg x b x wt/day for a period of six weeks. To elucidate the region specific response, study was carried out in two different regions of brain namely cerebrum and cerebellum. Following aluminium exposure, a significant decrease in the activities of enzymes namely Hexokinase, Lactate dehydrogenase, Succinate dehydrogenase, Mg(2+) dependent ATPase was observed in both the regions. Moreover, the activity of acetylcholinesterase was also reported to be significantly decreased. Post-treatment with centrophenoxine was able to restore the altered enzyme activities and the effect was observed in both the regions of brain although the activity of lactate dehydrogenase and acetylcholinesterase did not register significant increase in the cerebellum region. Further, centrophenoxine was able to improve the altered short-term memory and cognitive performance resulted from aluminium exposure. From the present study, it can be concluded that centrophenoxine has a potential and can be exploited in other toxicological conditions also.

Reversal of an aluminium induced alteration in redox status in different regions of rat brain by administration of centrophenoxine

Aluminium is one of the most studied neurotoxin, and its effects on nervous system are both structural and functional, involving various regions of brain. Aluminium toxicity is known to have multiple mechanisms of action in the central nervous system. Affinity of aluminium for thiol substrates is considered a possible molecular mechanism involved in aluminium neurotoxicity. The reduced glutathione (GSH) is especially important for cellular defence against aluminium toxicity. This study pertains to the modulatory action of centrophenoxine on GSH status in aluminium exposed different brain regions of the female rats. Aluminium was administered orally at a dose of 40 mg/Kg x b x wt x /day for a period of eight weeks whereas, centrophenoxine was administered intraperitoneally at a dose of 100 mg/Kg x b x wt x /day for a period of six weeks. The study was carried out in different regions of brain namely cerebrum, cerebellum, medulla oblongata and hypothalamus. Animals exposed to aluminum, registered a significant decrease in the levels of reduced glutathione, and oxidized glutathione as well as in the activity of glutathione reductase in all the different regions studied when compared to normal control animals. Post-treatment with centrophenoxine, showed a significant improvement in the thiol levels in different regions. Centrophenoxine when administered alone also had a profound effect on the levels of reduced glutathione as well as on the activity of glutathione reductase. From the present results, it can be stated that centrophenoxine administration, as a thiol-antioxidant, arrests the aluminium induced cellular damage by improving the thiol status in brain regions.

Pharmacological interventions against aging through the cell plasma membrane: a review of the experimental results obtained in animals and humans

As was shown in a recent review by this author (Ann. N.Y. Acad. Sci., 928: 187-199, 2001), oxyradicals cannot be considered only as harmful by-products of the oxidative metabolism, but living cells and organisms implicitly require their production. This idea is supported by numerous facts and arguments, the most important of which is that the complete inhibition of the oxyradical production by KCN (or by any block of respiration) kills the living organisms long before the energy reserves would be exhausted. This new theoretical approach not only helps our understanding of the normal functions of the living organisms, such as the basic memory mechanisms in the brain cells, but also helps in identifying the site-specific, radical-induced damaging mechanisms that represent the undesirable side effects of oxygen free radicals. First of all, these effects make the cell plasma membrane vulnerable and cause a series of intracellular functional disorders, as described by the membrane hypothesis of aging (MHA). The logical way for any antiaging intervention therefore should be to increase the available number of loosely bound electrons inside the plasma membrane that are easily accessible for OH(*) free radical scavenging. The present review summarizes the available knowledge regarding the theory of the use of membrane-related antiaging pharmaca, like centrophenoxine (CPH), tested in both animal experiments and human clinical trials. A modified, developed version of CPH coded as BCE-001 is also reported.

Gerontopsychological studies using NAI ('Nürnberger Alters-Inventar') on patients with organic psychosyndrome (DSM III, Category 1) treated with centrophenoxine in a double blind, comparative, randomized clinical trial

A double blind clinical trial was performed on 50 persons (25 men, 25 women) over the age 60 (average age: 77 years). They suffered from dementias of medium level (DSM III, Category 1, ICD No. 299), and had been residents in an old age home longer than 3 months at the start of the trial. The patients were treated first for 2 weeks by placebo tablets and their initial performance was recorded during this period by using the Nuremberg Gerontopsychological Inventory (NAI). This was then followed by a treatment for 8 weeks with the nootropic drug, centrophenoxine (CPH), the dose of which was 2 g/day distributed in 2 x 2 tablets of Helfergin500 (Promonta, Hamburg, FRG), or with placebo tablets of identical size, then the NAI test was repeated again. Verum or placebo treatment was selected randomly and the code was revealed only after having elaborated all the results of the trial. During the treatment period four drop-outs occurred for intercurrent diseases. Evaluation was based on a semi-quantitative, intra-individual comparison of the performance before and after treatment. The results obtained suggest that CPH treatment may be useful in dementias of medium level in quite old groups of patients, since 48% of the verum group displayed improvements in the memory functions against 28% of the placebo group. CPH seems to be a useful and harmless drug in the treatment and most probably also in prevention of the dementias.

Neuronal lipopigment: a marker for cognitive impairment and long-term effects of psychotropic drugs

Lipopigment, identifiable in the fluorescence microscope, is thought to be cellular debris partly derived from free-radical-induced peroxidation of cellular constituents. The volume of neuronal lipopigment has been positively correlated with advancing age, Alzheimer dementia, and the neuronal ceroidoses, while various changes in neuronal lipopigment have been reported in association with the chronic administration of dihydroergotoxine, ethanol, phenytoin, centrophenoxine, and chlorpromazine. An increase in the volume of neuronal lipopigment may indicate increased functional activity of the cell, impaired removal of pigment or anoxia. Chronic administration of agents which can be correlated with decreased neuronal lipopigment in animal models might protect neuronal function against any adverse effects associated with (but not necessarily resulting from) lipopigment accumulation in normal ageing, anoxia, or certain degenerative diseases. Long-term studies of the prophylactic use of such agents, or of drugs which neutralise free radicals, may be indicated. Other clinical applications of such drugs may include protection against the effects of free radicals formed during periods of oxygen deprivation.

Dysdifferentiation hypothesis of aging and cancer: a comparison with the membrane hypothesis of aging

Our laboratories have been testing the basic concept that the age-dependent deterioration of the molecular components of living systems may be due in part to the biochemical effects of active oxygen species. The dysdifferentiation hypothesis of aging and cancer (DHAC) as well as the membrane hypothesis of aging (MHA) are discussed and compared to each other. These two hypotheses consider cellular mechanisms through which free radical-induced alterations may lead to the aging process. DHAC emphasizes the importance of the instability of the differentiated state of cells and how active oxygen species may interact with the genetic apparatus of cells, leading to improper gene regulation. The evidence supporting this hypothesis includes an age-dependent increase in the expression of specific genes that normally are expected to be repressed. Such evidence now includes the c-myc oncogene as well as an age-dependent decrease in the average methylation level of the entire genome in liver tissue of mice. The central concept of DHAC is that aging is a result of gene regulatory instability and that lifespan is governed by mechanisms acting to stabilize proper gene regulation. MHA is based on the concept that all cellular components are exposed to free-radical attacks, and that the damaging efficiency of the radicals is density-dependent. Compact structures like membranes are consequently more susceptible to damage than cytosolic components. In addition, the cell plasma membrane is exposed to another damaging effect called residual heat damage, which is due to the depolarization-induced discharge of the membrane during the action potential. MHA predicts that a key process of normal differentiation as well as aging is a continuous, age-dependent loss of the passive permeability of the cell membrane for potassium and probably also for water. This is due to a constant difference between the rates of damage and replacement of the membrane components and results in a gradual dehydration of the intracellular mass from the embryonic state to the aging state. The increasing intracellular density will eventually become rate-limiting for many different cellular functions, resulting in the cessation of growth and the beginning of aging. MHA also predicts an overall decrease of gene expression and protein turnover rate during aging. Pharmacological interventions on the cell membrane have supported the validity of MHA and have indicated specific mechanisms of how aging and dysdifferentiation may occur.

Age-related change in the multiple unit activity of the rat brain parietal cortex and the effect of centrophenoxine

In this study, spontaneous multiple unit activity (MUA, action potentials derived simultaneously from a number of neurons in a given brain region) was recorded through electrodes chronically implanted in the parietal cerebral cortex of the rats of 1, 3, 6, 9, 12, and 26 months of age (cross-sectional study). Electrophysiological recordings were obtained from unrestrained conscious rats using standard techniques. The results indicated that multiple unit activity was decreased with aging (senescence). Maximum firing rate (MUA counts) was found at the age of 3 months. At 6 months of age, the MUA was decreased by about 30%, while during 6 to 12 months of age the activity seemed to remain unchanged. At 26 months of age the firing rate was, however, further decreased (about 40%). Centrophenoxine administration led to an increase in MUA in the rats of 12 and 26 months of age. The results, thus, further showed that centrophenoxine, a nootropic drug known for its antiaging effects in experimental animals as well as in humans, also manifested beneficial effects electrophysiologically. The data presented in this work are new and significant, since although age effects on gross electrophysiological signals (EEG, evoked potentials, etc.) are known, the aging changes in cellular level electrophysiological signals (action potentials) have not been generally studied particularly in conscious animals.

Fluidizing effects of centrophenoxine in vitro on brain and liver membranes from different age groups of mice

This study examined the effects of different concentrations of centrophenoxine on physical properties of synaptic plasma membranes and liver microsomes using electron spin resonance procedures. Membranes of different age groups of mice were labeled with the 5-doxyl stearic acid spin-label and membrane fluidity determined in the presence and absence of different concentrations of centrophenoxine. Centrophenoxine had a direct effect on membranes as shown by a significant increase in membrane fluidity. This effect was greatest in liver microsomes as compared to synaptic plasma membranes. Age differences were not observed in centrophenoxine-induced fluidization. Effects of centrophenoxine in vivo may be due in part to the drug acting directly on the physical properties of the membrane lipid environment.

Age-dependent alterations of the intracellular water and electrolyte content of heart and muscle cells

Age-dependent alterations in intracellular concentrations of monovalent ions (Na+, K+ and Cl-) were measured in heart and muscle cells of rats using energy dispersive X-ray microanalysis of bulk specimens. Separate measurements were performed in order to get the elemental concentrations in the dry mass of the cells, and to determine the intracellular water and dry-mass content. The in vivo concentrations were calculated from these two measurements assuming that the monovalent ions were dissolved in the cell water. A statistically significant decrease was measured in the water content of the myocytes of old rats, suggesting an increase in density and viscosity of the cytoplasmic colloid during aging. This loss of cellular water was accompanied by a significant increase in both the single ion concentrations and the total monovalent ion content of the intracellular water. These age-dependent alterations in heart and muscle cells are similar to those demonstrated previously in neurons and hepatocytes.

Loss of water from heart muscle cells during aging of rats as measured by X-ray microanalysis

Age-dependent changes of the intracellular water content (IWC) of the rat myocardium have been measured by X-ray microanalysis of deep-frozen bulk specimens (Zs.-Nagy et al., 1982), using a slow warming up and drying of a very superficial layer of the sample, in order to minimize space charging effects. These results were compared with those calculated from the conventionally measured tissue water contents (TWC) and data from literature of morphologically estimated volume density of the extracellular space (David et al., 1981). The IWC values obtained from these two independent methods are in very good agreement, showing that the etching of the surface during the bulk specimen analysis is sufficiently small, i.e., it does not result in any considerable error in the quantitative X-ray microanalysis. The IWC of heart muscle cells decreases significantly with advancing age (from about 80% by weight at the age of 14 days to 71% by the age of 24 months). This observation is consistent with the membrane hypothesis of aging (Zs.-Nagy, 1978). Comparison of the IWC with TWC of the heart muscle shows that the increase of the volume density of the extracellular space during aging balances the age-dependent loss of myocytes to a certain extent.

Studies on the effect of iron overload on rat cortex synaptosomal membranes

Iron as ferrous ammonium sulfate was injected into the cerebral spinal fluid of rats. After three consecutive days of injection of 4 mumol of iron, the total iron content of brain cortex synaptosomes from the iron-treated animals was 2-fold higher than that from control animals receiving the saline vehicle only. Spin label studies of the synaptosomal membranes demonstrated that the lipid region of the membranes became more rigid and, in addition, the mobility of labeled SH groups of membrane proteins decreased after the iron treatment. The cholesterol content was significantly higher in iron-treated animals as compared to controls. Centrophenoxine pretreatment (100 mg/kg body weight daily for 6 weeks) diminished the iron effects. Synaptosomal membrane alterations observed after iron treatment were similar to changes observed previously during aging. This lends support to the notion that free-radical induced damage occurs in brain membranes with increasing age.

Verification of the membrane hypothesis of aging on the identified giant neurons of the snail Lymnaea stagnalis L. (Gastropoda, Pulmonata) by a combined application of intracellular electrophysiology and X-ray microanalysis

The validity of the membrane hypothesis of aging (Zs.-Nagy, 1978) was tested on identified giant neurons of the snail Lymnaea stagnalis L. by using a combination of intracellular microelectrophysiology and X-ray microanalysis of the intracellular water and electrolyte concentrations on the very same cells. The snails were taken from an inbred stock and divided into young, adult and old age groups (3, 12 and 24 mth, respectively). The giant neuron called LPa-2 from the left parietal ganglion was selected for the studies. The resting potential of the cell membrane was recorded by means of intracellular microelectrode technique. The very same cells were then explored by freeze fracture and analyzed by an energy dispersive bulk specimen method of X-ray microanalysis. The resting membrane potential displayed an age-dependent hyperpolarization, the intracellular water content decreased considerably and the intracellular potassium concentration increased almost 90% by old age. The relative passive permeability ratio for potassium (PK) and chloride (PCl) was calculated from the measured data by means of the Goldman-Hodgkin-Katz equation. Such calculations revealed that PK decreases nearly 50% with age causing the increase of the intracellular potassium content, and this is accompanied also by a significant decrease of the PCl. The results support the validity of the membrane hypothesis of aging and are in agreement with the general knowledge regarding the electrophysiological behaviour of the giant neurons of Gastropode snails.

Superoxide radical scavenging ability of centrophenoxine and its salt dependence in vitro

The superoxide radical scavenging ability of centrophenoxine (CPH) and its components (dimethylaminoethanol = DMAE, p-chlorophenoxyacetic acid = PCPA) was studied in vitro using the method of pyrogallol autoxidation, cytochrome c reduction and photoxidation of o-dianisidine in salt-free assay media and in the presence of increasing NaCl or KCl concentrations. The CPH proved to be a superoxide radical scavenger in all three systems used, however, the rate constant for this reaction was rather low (1.7 X 10(2) M-1 s-1). This scavenging ability decreased linearly with increasing ionic strength. DMAE and PCPA behaved in a somewhat contradictory manner. The former proved to be a weak superoxide radical generating compound being partially sensitive to the ionic strength. The latter showed either superoxide radical scavenging or generating effects in various assays depending on the actual salt concentrations of the media. On the basis of the results one has to assume that the superoxide radical scavenger ability of CPH may hardly be responsible for the in vivo effects of this compound, therefore, its OH. radical scavenger reactions the rate constant of which is about 10(9) M-1 s-1 may be of much greater importance.

Alterations in the molecular weight distribution of proteins in rat brain synaptosomes during aging and centrophenoxine treatment of old rats

Properly prepared membrane proteins of brain synaptosomes of 2-, 12- and 24-month-old CFY female rats were filtrated on a Sepharose 2B gel. The molecular weight distribution showed an age-dependence: there was a clear shift toward the higher molecular weights in the adult and old rats. The observed alterations reflect an increased cross-linking of the proteins during aging due most probably to the OH free radical damage of the cell components. Centrophenoxine treatment for 2 months reversed this phenomenon in the old animals: the high molecular weight fractions decreased and the lower ones increased in the treated animals as compared to the old, untreated rats. The results support the membrane hypothesis of aging and contribute to a better understanding of the biological effects of centrophenoxine.

Effects of ionic strength on the activity of superoxide dismutase in vitro

Changes in superoxide dismutase (SOD) activity were studied in vitro at increasing NaCl or KCl concentrations. SOD activity was measured using two different systems of superoxide radical generation: pyrogallol autoxidation, and xanthine-xanthine oxidase reaction. Pyrogallol autoxidation was directly measured by spectrophotometry, whereas in the second case cytochrome c reduction was followed at 550 nm. The inhibition of SOD on those parameters was taken as measure of SOD activity. Increasing concentrations of NaCl and KCI significantly increased the rate of pyrogallol autoxidation. The inhibitory effect of SOD significantly decreased under the influence of these salts and followed an exponential curve. The two salts studied resulted in essentially identical changes in SOD activity. Increasing concentrations of NaCl and KCl decreased the rate of cytochrome c reduction in the xanthine-xanthine oxidase system. When correcting the results for these primary effects, SOD activity also displayed in this system an exponential decay with increasing salt concentrations. The results are interpreted in terms of the known charge distribution pattern on the surface of the SOD molecule, and of the age-dependent increase of the intracellular potassium and sodium concentrations in the postmitotic cells.

Electron spin resonance spectroscopic demonstration of the hydroxyl free radical scavenger properties of dimethylaminoethanol in spin trapping experiments confirming the molecular basis for the biological effects of centrophenoxine

The ADP-Fe(II)-H2O2 system generates OH free radicals which can be trapped by 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) thus yielding a measurable signal by electron spin resonance spectroscopy. The amount of DMPO-OH spin adduct formed under certain conditions decreased considerably, if dimethylaminoethanol (DMAE), p-chlorophenoxyacetic acid (PCPA) or centrophenoxine (CPH) were present in comparable concentrations to that of DMPO. It has been demonstrated that such an effect cannot be attributed to any interference of the tested compounds with the Fe(II) and its oxidability by H2O2. The reaction of DMAE with OH free radicals was demonstrated also by using other spin traps. These spin traps reacted with OH free radicals either not at all (phenyl-tert-butylnitrone, PBN) or only to a slight extent (alfa-pyridyl-l-oxide-N-tert-butylnitrone, 4-POBN). DMAE was also a competitive OH free radical scavenger with proline and hydroxyproline, both of which have recently been shown to react with OH free radicals to form nitroxyl free radicals. On the basis of the experimental results, the OH free radical scavenger property of DMAE can be regarded as firmly established. This result supports the molecular mechanism proposed for the explanation of the anti-aging effects of CPH in terms of the membrane hypothesis of aging.

Age-dependent decrease of the passive Rb+ and K+ permeability of the nerve cell membranes in rat brain cortex as revealed by in vivo measurement of the Rb+ discrimination ratio

Young, adult and old male CFY rats (2, 12 and 24 mth of age, respectively) were treated with a daily dose of 30 mg RbCl/100 g body weight, in form of aqueous solution injected intraperitoneally for 14 days. A considerable part of the intracellular K+-content of the body was replaced by Rb+ during this treatment. After cessation of the RbCl injections, a relative steady state came into being in each age group, called Rb+-release period. During this period Rb+ and K+ contents of the blood serum and the cisternal CSF were measured by atomic absorption spectrophotometry, and of the intracellular space of brain cortical cells by energy-dispersive X-ray microanalysis. Ultrastructural features of the brain cortex were also checked by transmission electron microscopy. For X-ray microanalysis, the L-line of Rb at 1.694 keV energy was used at 10 kV accelerating voltage in a scanning electron microscope equipped with an EDAX System F. Rb+ and K+ concentrations were obtained for the cellular dry mass and converted into wet concentrations on the basis of intracellular water contents known from former experiments. Rb+-replacement of K+ did not cause any ultrastructural alteration in the brain cortex. However, the Rb+ accumulation displayed a very significant age-dependent increase: at the beginning of release, adult and old rats had 32.6 and 44.7 mM Rb+ in their intracellular water as against the 8.6 mM found in the young group, and similar proportional difference persisted during 20 days of the release. Rb+ discrimination ratios (DR) calculated either for the blood or the CSF displayed very considerable age-dependent increase: the values of the adult and old groups were 191 and 242% of the young one, indicating that the passive Rb+ (and K+) permeability of the nerve cell membrane decreases throughout the life span of rats. These results give further support to the membrane hypothesis of aging.

Cytochemical interaction of nucleolus and cytoplasm in the Purkinje cells of senile white rats under the influence of centrophenoxine

Senile white rats were treated with centrophenoxine at a dosage of 100 mg/Kg body weight/day for 60 days intraperitoneally. Sections of variously fixed and embedded cerebella were studied cytochemically to note the effect of the drug on the senile Purkinje neurons. The nucleolus was found to be hyper-active, as evidenced by the processes of budding and extrusion. A frank regeneration of the Nissl patches along with an increase in alpha-esterase and decrease in the activity of acid phosphatase and simple esterase was noted in the Purkinje cells after 60 days' treatment. It is suggested that the drug exerts its positive effects by regenerating the general cytoplasm and by revitalizing the nucleocytoplasmic interactions in the senile Purkinje cells.

Centrophenoxine increases the rates of total and mRNA synthesis in the brain cortex of old rats: an explanation of its action in terms of the membrane hypothesis of aging

The rates of total and polyA+ RNA (mRNA) synthesis were measured by radioisotope technique in the brain cortex of female CFY rats. There was practically no significant difference between the young (1.5 months) and adult (13 months) rats; however, the old group (26 months) displayed a considerable decrease of the rates of synthesis of both classes of RNA studied. Centrophenoxine treatment (100 mg per kg body weight per day, for 2 months) reversed this tendency, and increased significantly the synthesis rates of old rats almost to the adult level. The results are interpreted in terms of the membrane hypothesis of aging, attributing a free-radical scavenger function of the dimethylamino-ethanol incorporated into the nerve cell membrane from the centrophenoxine.

In vivo stimulation of nerve cells by phytohemagglutinin. II. Alterations in the rate of total and mRNA synthesis in the brain cortex of old rats

Bacto-phytohemagglutinin-P (PHA-P) was administered in form of a single intralumbar injection of 2 mg/100 g body weight dose to 24- to 28-mth-old female CGY rats. The accuracy of the injection technique was checked by adding 2% lidocaine to the injection mixture, which resulted in a transient and symmetric paralysis of the posterior limbs when reaching the cerebrospinal fluid. The total RNA content of the liver and brain cortex were measured, and phenolic extraction of RNA was performed the brain cortex. Poly(A) +RNA (mRNA) was separated from the total RNA of the brain cortex by oligo(dT)-cellulose chromatography. Pulse labeling with tritiated uridine was performed 45 min before killing the animals and the incorporation of the radiolabel was measured in the respective RNA classes and corrected for the nucleotide pool size. The rates of total and mRNA synthesis are expressed in percentages of the young untreated rats and compared to old untreated animals. The effects of PHA-P was studied at 4, 10, 20 and 44 h after its injection. A considerable increase of the total RNA content of the brain cortex was measured during the first 10 h of the experiment followed by a slow decrease. However, the RNA content of the brain cortex was still significantly higher at the end of experiment compared to untreated old rats. The rate of total RNA synthesis increased significantly during the first 10 h and remained constantly high until 44 h. The rate of mRNA synthesis increased to a higher extent than that of the total RNA, and also remained high until 44 h.

Alterations of the synaptosomal membrane 'microviscosity' in the brain cortex of rats during aging and centrophenoxine treatment

Synaptosomal and myelin fractions were isolated from the brain cortex of young, adult and old male CFY rats (2, 12 and 24 mth, respectively). The purity of the fractions was tested by transmission electron microscopy and marker enzyme assays. The cholesterol content of the fractions was also determined. Samples of the fractions were labelled with diphenylhexatriene (DPH) and the fluorescence anisotropy (r) of the label was measured at various optical densities. The values of r extrapolated to zero optical density were compared in the age groups and used for calculating the 'microviscosity' of the membranes. The 'microviscosity' of synaptosomal membranes displayed a significant age-dependent increase: from 2.3 +/- 0.02 (SD) in the young group it increased to 2.6 +/- 0.03 poise by the age of 24 mth at 37 degrees C. Most of this increase occurred between the adult and old age. The cholesterol content of the synaptosomes also increased significantly during aging. Centrophenoxine (CPH)-treatment with 100 mg/kg body weight daily dose for 2 mth was able to reverse the age-dependent alterations of both the membrane 'microviscosity' and the cholesterol content in the synaptosomes: the values returned nearly to the adult level. The results obtained are interpreted in terms of the membrane hypothesis of aging attributing to primary role to the free-radical induced membrane damage in cellular aging.

Effect of centrophenoxine on the antioxidative enzymes in various regions of the aging rat brain

This study investigated the effect (in vivo) of centrophenoxine (Helfergin) on the activity of antioxidant enzymes (glutathione peroxidase GSH-PER, glutathione reductase GSSG-RED, superoxide dismutase SOD and catalase) in subcellular fractions from the regions of the brain (cerebrum, cerebellum and brain stem) of rats aged 6, 9 and 12 months. In all age groups, normal (control) activity of GSH-PER, GSSG-RED and SOD in the three brain regions was higher in the soluble fractions than in the particulate fractions. The three regions of the brain showed different levels of the enzyme activities. Enzymes in soluble fractions (except GSSG-RED in cerebrum of rats aged 12 months) did not change with age. In particulate fractions, however, the enzymes showed age-related changes: GSH-PER decreased with age in cerebellum and brain stem, but showed an age-related increase in cerebrum, GSSG-RED and SOD increased with age in all the three brain regions. Catalase activity in all the three brain regions remained unchanged in all age groups. Six week administration of centrophenoxine (once a day in doses of 80 mg/Kg and 120 mg/Kg) to the experimental animals produced increases in the activity of SOD, GSH-PER and GSSG-RED in particulate fractions from all the three brain regions. In the soluble fractions, however, only SOD and GSH-PER activity was increased. In vitro also centrophenoxine stimulated the activity of GSH-PER. A dosage of 80 mg/Kg produced greater changes than a 120 mg/Kg dosage. The drug had no effect on the activity of catalase. Centrophenoxine also reduced lipofuscin deposits (studied both biochemically and histochemically) thus indicating that the drug inhibited lipofuscin accumulation by elevating the activity of the antioxidant enzymes. The data suggest that alleviation of senescence by centrophenoxine may, at least, partly be due to activation by it of antioxidant enzymes.

The effect of acute and chronic centrophenoxine treatment on the synaptic plasticity of old rats

The cerebellar glomerulus was studied by electron microscopic morphometry in female Wistar rats. Age-dependent alterations have been revealed from 3 to 28 mth of age, and the effect of centrophenoxine (CPH) was analyzed in two different patterns of administration. First, 27-mth-old rats were treated daily for 6 wk (acute treatment), and second, 18-mth-old rats were treated 3 times per week for 5 months (chronic treatment). The dose was 100 mg CPH/kg body weight, injected intraperitoneally. The surface density (SV), the numerical density (NV) and the average length (L) of the synaptic junctions were calculated from data obtained on ethanol-phosphotungstic acid stained ultrathin sections. An age-dependent reduction of SV and NV of the synaptic contact zones was found, and the L increased in the oldest animals. CPH-treatment resulted in a marked increase of SV in both types of application, whereas the other two parameters behaved differently in the two groups. The chronic treatment resulted in a significant slowing down of the decrease of NV, whereas L remained invariate. On the contrary, the acute treatment increased L but did not alter significantly NV. The results and the differences between the treatment types are discussed in terms of synaptic plasticity and are interpreted as different manifestations of the same reactive synaptogenetic process.

In vivo studies on the age-dependent decrease of the rates of total and mRNA synthesis in the brain cortex of rats

The membrane hypothesis of aging (Zs.-Nagy, I., 1978, J. Theor. Biol. 75, 189-195) attributes the primary role in cellular aging to an age-dependent decrease of the passive potassium permeability of the cell membrane which is due most probably to free-radical damage of the membrane components. As a consequence, the intracellular and intranuclear ionic strength increases resulting in a condensation of the chromatin and a slowing down of the synthetic processes performed by the nucleus. In this concept it was of importance to reveal whether the rates of total and mRNA synthesis display any age-dependent alteration parallel with the change of membrane permeability of the brain nerve cells. Experiments were performed using tritiated uridine incorporation measurements and suitable preparation techniques in young, adult and old rats (1.5, 13 and 25 mth of age, respectively). Comparisons of the incorporation rates revealed a very considerable decrease in the rate of synthesis of both the total and polyadenylated RNA (polyA + RNA) between the ages of 13 and 26 mth. The old animals displayed only about 55 and 67% of the rate of synthesis for the 2 classes of RNA, respectively, as compared to the young and adult rats, if the results are expressed as dpm/mg RNA. However, the decreases are even more pronounced (34 and 41%) if the results are expressed on a dry weight basis. The results obtained are compatible with the membrane hypothesis of aging.

Intracellular water and dry mass content as measured in bulk specimens by energy-dispersive X-ray microanalysis

Intracellular water content (IWC) was measured in freeze-fractured biological bulk specimens by means of energy-dispersive X-ray microanalysis. The method is based on the concentration differences of certain elements (potassium and phosphorus) between frozen-hydrated and frozen-dried states of the tissues as applied formerly to sectioned material by others. A new mathematical formula has been derived giving rather precise figures for IWC. No elemental standards are necessary for the measurement: one has to obtain only the peak to background ratios in wet and dry states of the cells. the method is sensitive enough to reveal age-dependent as well as drug-induced changes of IWC in liver and brain cells. The values obtained are quite comparable with the theoretically expected one. Technical problems of the application of this method are discussed in detail.

In vivo effects of vitamin E deficiency on the intracellular monovalent electrolyte concentrations in brain and liver of rat. An energy dispersive X-ray microanalytic study

Vitamin E is known to play a protective role for cell membranes against free-radical attacks. Vitamin E deficiency causes a rapid macroscopic ageing of rats. On the other hand, during normal ageing, cell membranes undergo functional alterations resulting in an increased intracellular potassium concentration in brain and liver cells. Therefore, is was of interest to study whether vitamin E deficiency produces similar alterations in young rats. Female Wistar rats were fed with a vitamin E deficient diet from 1 month of age for 10 months. The parietal brain cortex and the liver were analyzed by means of a quantitative energy dispersive X-ray microanalytic method using a JEOL JSM-35C-EDAX-711-NOVA-3 system. Monovalent electrolyte contents as well as the water content of the cells were determined in 5 treated and 5 control animals. Water content was measured by analyzing the potassium content in aqueous, frozen state, and again in the dry mass of the cells. On the basis of these data, a computer program calculated the water proportions. Average values for 200 or more cells of each organ per group revealed a significant increase in the intracellular potassium content of the brain cells, whereas the sodium and chloride contents increased to a much lower extent. There was a 2.6% loss of intracellular water in the brain cells in the vitamin E deficient group. The liver monovalent ions and water content remained unchanged. The results obtained are discussed in terms of the membrane hypothesis of ageing.

Morphometric studies on synapses of the cerebellar glomerulus: the effect of centrophenoxine treatment in old rats

Young, adult and old female Wistar rats (3, 18 and 28 months of age, respectively), were studied using electron-microscopic stereology. Synaptic parameters of the cerebellar glomerulus were calculated and compared with similar data obtained from old Wistar rats of the same breed treated with centrophenoxine (CPH; HelferginR, Promonta, Hamburg) in the form of intraperitoneal injections (100 mg/kg body weight) for 40 days. This treatment resulted in a sort of "rejuvenation" of synaptic structures. Namely, the surface density and the total length of synaptic contact zones were markedly reduced in the untreated old group, but in the treated animals these parameters returned to the values found in the young and adult animals. At the same time the numerical density of synapses remained unaltered in the treated group, while the average synaptic length displayed some further increase. The results are interpreted in terms of the age-dependent decrease in reactive synaptogenesis, suggesting that CPH stimulates the metabolism of the nervous elements persisting in old brain. The possible mechanism of CPH effect is also discussed.

On the role of cross-linking of cellular proteins in aging

Water-insoluble protein fractions increase in the brain cortical tissue and liver of rats during aging in both sexes. This suggests a possible increase in the cross-linking of proteins which may be due to the formation of, for example, hydroxyl free radicals during several metabolic processes. In vivo application of centrophenoxine causes a reversal of this phenomenon in old rats. In vitro experiments show that the generation of hydroxyl free radicals by chemical systems like homolysis of H2O2 by redox coupling with Fe2+ leads to Fe3+ conversion, results in the cross-linking of bovine serum albumin and the mixed proteins of liver or brain homogenates of young rats. The cross-linked proteins have a very much increased molecular weight, they become mostly insoluble even in 6 M urea. Dimethylaminoethanol, the effective part of the centrophenoxine molecules, is able to diminish the extent of cross-linking, acting most probably as a free-radical scavenger. The results are discussed in terms of the "membrane hypothesis of aging". A molecular basis is proposed for the anti-aging effect of centrophenoxine.