Antagonistic effect of sodium hydroxybutyrate on several effects of aminoxyacetic acid]

A well-known protective effect of aminooxyacetic acid against thiosemicarbazide convulsions was confirmed; it was shown that a similar, although somewhat weaker activity, was exerted by sodium hydroxybutyrate. Surprisingly, the effect of aminooxyacetic acid was diminished by sodium hydroxybutyrate. Sodium hydroxybutyrate in combination with aminooxyacetic acid decreased the protective activity of the latter against thiosemicarbazide convulsions and diminished the extent of GABA accumulation characteristic of aminooxyacetic acid action. This effect is attributed to the competition between the aminooxyacetic acid, sodium hydroxybutyrate and GABA for alpha-ketoglutarate-GABA-transaminase and possible for the GABA-ergic receptor.     

Prophylactic effects of sodium oxybutyrate and lithium oxybutyrate on stress-induced depression of the activity of normal killers in mice

The possible use of sodium hydroxybutyrate and lithium hydroxybutyrate for the prevention of the decrease in splenic natural killer activity has been studied in CBA mice upon 6-hour immobilization stress. Both agents proved to be effective in preventing stress-induced depression of NK activity. However, a protective effect of lithium hydroxybutyrate was observed at a dose 4 times lower than that of sodium hydroxybutyrate.     

State of the peripheral catecholaminergic systems during pharmacologic correction of immobilization stress using sodium oxybutyrate

Fluorescent microscopy and spectrofluorometry of biogenic amines were employed to study the peripheral catecholaminergic systems in immobilized rats which received sodium hydroxybutyrate. The content of catecholamines was measured in the adrenergic nerves of dura mater, vas deferens and chromaffin tissue of the adrenals. It was established that sodium hydroxybutyrate in a dose of 40 mg/kg intraperitoneally promoted returning to normal of the adrenergic mediator activity during alarm and resistance stages. The role of the peripheral catecholaminergic systems in the mechanism of the stress-protective effect of sodium hydroxybutyrate is discussed.     

Effect of sodium oxybutyrate on regional blood circulation and on neural regulation of vascular tonus]

The effect of sodium hydroxybutyrate on the blood flow in the aorta, carotid, mesenteric and femoral arteries were studied on cats and dogs. The circulation was assessed by the electromagnetic and resistographic methods, in the anesthetized and nonanesthetized animals. The tonic activity was recorded in the sympathetic nerves and the EEG. Sodium hydroxybutrate was shown to decrease the sympathetic activity, resulting in the increase of the regional circulation and induced the EEG synchronization. The latter effect was more pronounced in the arotid arteries. It can be assumed that sodium hydroxybutyrate affects the nervous control of the blood vessels.     

Redistribution of myocardial blood flow in chronic ischemia under the effects of pharmacological agents

In the experiments with anesthetized dogs under chronic myocardial ischemia the effect of propranolol, diltiazem, lithium and sodium hydroxybutyrate on the myocardial blood flow redistribution was studied with the help of ultrasonic method. The redistribution was estimated by the ratio change of blood flows in veins which drain blood directly from the focus of myocardial ischemia and total myocardial of left ventricular (v cardiac magna). It was established that propranolol increases the ratio and diltiazem decreases it. Some differences in the effect of antihypoxic drugs were revealed. Sodium hydroxybutyrate redistributed the blood flow in favour of the focus of myocardial ischemia and lithium hydroxybutyrate increased the blood flow both in the focus of myocardial ischemia and in the conditionally-intact region of myocardium of left ventricular.     

Effect of lithium salts on neuropathological syndromes of spinal origin

Experiments on noninbred rats were made to study the influence of lithium hydroxybutyrate on two patterns of spinal cord pathology: the generalized myoclonus and painful syndrome of spinal origin. The syndromes were induced by generators of pathologically enhanced excitation in the ventral and dorsal horns of the spinal cord. The effects of lithium chloride and sodium hydroxybutyrate were examined to compare the influence of lithium (cation) and hydroxybutyrate (anion) components to elucidate the role of each of the components. Lithium hydroxybutyrate appeared more effective, since it inhibited the generator of pathologically enhanced excitation in the appropriate structures, provoking the anticonvulsant effect in myoclonus and suppressing the painful syndrome.     

Study of the mechanism of the anti-hypoxic action of lithium oxybutyrate using cerebral ischemia as a model

A study was made of energy metabolism and concentration of malonic dialdehyde (MDA) in cerebral tissue of mice given sodium hydroxybutyrate and lithium hydroxybutyrate 30 and 60 s after decapitation. Administration of lithium hydroxybutyrate brought about a more economic consumption of the glycogen pool as compared with "hypoxic" control. The differences were revealed in the action of both salts on ATP. The concentration of MDA declined after their administration, lithium hydroxybutyrate being more efficacious. The possible mechanisms of the action of lithium hydroxybutyrate are discussed.     

Effect of sodium hydroxybutyrate on the ultrastructure of cross-striated muscle tissue myocytes during physical exercise

The ultrastructure of myocytes of the rat myocardium and skeletal muscles was studied in the control during physical exercise and under conditions of two-week sodium hydroxybutyrate pretreatment. It was shown that single maximum physical exercise caused significant changes in the fine structure of cardiomyocytes and somewhat less changes in a pronounced intermyofibrillar edema, the swelling of mitochondria and an acute fall of the glycogen level. A two-week sodium hydroxybutyrate pretreatment prevented the changes in the myocytes. The observed structure normalization induced by the drug is likely to be due to the specific nature of its metabolic transformation and to the effect on the energy exchange.     

Comparative study of several preparations in different models of cerebral hypoxia

The antihypoxic effects of gutimine, piracetam, sodium hydroxybutyrate and lithium hydroxybityrate were studied on different models of brain hypoxia. All the drugs under study produced a remarkable antihypoxic effect in experimental asphyxic hypoxia, increasing brain resistance to oxygen deficiency and rapidly restituting brain function. Drug pretreatment of the animals with carotid artery occlusion raised the number of animals which survived 24 h after the operation. GABA salts appeared the most effective. Sodium hydroxybutyrate increased the lifespan of rats under histotoxic hypoxia.     

Protective effect of phenazepam and sodium oxybutyrate on somatic manifestations in immobilization stress

The effects of phenazepam and sodium hydroxybutyrate on the somatic manifestations, ultrastructure of the cortex and lipid content of the adrenals in rats exposed to immobilization were examined. Both the drugs had the stress-protective effect, decreasing the stress manifestations at alarm and resistance stages.     

Sodium oxybutyrate and piracetam acceleration of the compensatory-reparative processes after damage to the cerebral cortex in rats

The effects of sodium hydroxybutyrate and piracetam on compensatory-reparative processes in the central nervous system have been investigated in rats after extirpation of the frontal cortex. The animals were pretrained to conditioned reflex of active avoidance. Extirpation of the frontal cortex has been shown to disturb the conditioned reflex. Sodium hydroxybutyrate (50 mg/kg) and piracetam (200 mg/kg) were found to precipitate the recovery of the damaged reflexes.     

Antioxidant effects of antihypoxic drugs in cerebral ischemia]

Cerebral ischemia in rats (both carotid arteries occlusion) during 30 min, 3 hours and recirculation (1 hour) after ischemia (30 min) stimulated diene conjugates and fluorescent products accumulation in brain tissue. Intraperitoneal injection of sodium hydroxybutyrate (100 mg/kg), bemitil (50 mg/kg), ethomersol (50 mg/kg) reduced brain lipid peroxidation and did not yield in this respect to emoxypin (5 mg/kg). In contrast to emoxypin, sodium hydroxybutyrate, bemitil and ethomersol had no antiradical activity.     

Effect of the agents of general anesthesia on mice after microwave irradiation]

The general anesthetics chloroform, ftorotan, sodium thiopental and sodium hydroxybutyrate (500 mg/kg) decrease the survival of mice irradiated by microwaves. Ether, ftorotan, hexenal and sodium thiopental administered immediately after irradiation reduce the time of ensuing side position by 8-14%, its duration being decreased by 15-48% as compared to the control.     

Antihypoxic effect of glucosamine in acute hypoxic states in mice]

The preventive glucosamine injection causes an increase in the survival of mice with acute hypobaric hypoxia. The injection of glucosamine, combined with sodium hydroxybutyrate greatly increased their antihypoxic activities.     

Antagonism of piracetam with proline in relation to mnestic effects

Based on the authors' previous data showing that the lipophylic cethyl group promotes the penetration of amino acids through the blood-brain barrier, proline cethyl ester was synthesized and studied as a neuropharmacological tool. The substance administered to rats systemically (intraperitoneally) was shown to be able to provoke a deep amnesia when tested by the conditioned avoidance performance. Piracetam abolished the amnestic effect of proline cethyl ester while sodium hydroxybutyrate administered in the dosage range provoking the nootropic effect did not change that amnesia. The data suggest that proline may be considered as one of the possible endogenous amnestic factors. The close structural similarity of the piracetam cyclic fragment to proline, which resulted in their competition, appears to be one of the reasons for piracetam antiamnestic activity.     

Pharmacological correction of the disorders of cardiac contractile function in stress

It has been established that sodium hydroxybutyrate, prolactin, propranolol and ionol are capable of preventing the depression of the contractile function of the heart and of decreasing the glycogen level in the myocardium, provoked by emotional stress.     

The metabolic impact of β‐hydroxybutyrate on neurotransmission: Reduced glycolysis mediates changes in calcium responses and KATP channel receptor sensitivity

Glucose is the main energy substrate for neurons, and ketone bodies are known to be alternative substrates. However, the capacity of ketone bodies to support different neuronal functions is still unknown. Thus, a change in energy substrate from glucose alone to a combination of glucose and β‐hydroxybutyrate might change neuronal function as there is a known coupling between metabolism and neurotransmission. The purpose of this study was to shed light on the effects of the ketone body β‐hydroxybutyrate on glycolysis and neurotransmission in cultured murine glutamatergic neurons. Previous studies have shown an effect of β‐hydroxybutyrate on glucose metabolism, and the present study further specified this by showing attenuation of glycolysis when β‐hydroxybutyrate was present in these neurons. In addition, the NMDA receptor‐induced calcium responses in the neurons were diminished in the presence of β‐hydroxybutyrate, whereas a direct effect of the ketone body on transmitter release was absent. However, the presence of β‐hydroxybutyrate augmented transmitter release induced by the K_ATP channel blocker glibenclamide, thus giving an indirect indication of the involvement of K_ATP channels in the effects of ketone bodies on transmitter release.

     

Effect of neurotropic substances on sleep disorders caused by electrical stimulation of the hypothalamus in cats

The total period of sleep decreased as a result of the REM-sleep deficite following rage reaction induced in cats by the electrical stimulation of the hypothalamus. Haloperidol (1, 2, 3 mg/kg), diazepam (0.5, 1 mg/kg), nitrazepam (1, 6 mg/kg), glutetymide (10, 30, 60 mg/kg), pentobarbital (5, 15, 30 mg/kg) failed to eliminate sleep disturbances induced by rage reaction; lithium hydroxybutyrate (100, 150 mg/kg), dimedrol (1.5, 6 mg/kg) and imipramine increased the total sleep time on account of the slow wave phase; sodium hydroxybutyrate (100 mg/kg) normalized the electrophysiological pattern of sleep, decreasing the REM-sleep latency and the number of waking cats, and increasing the total REM-sleep time and the number of REM-sleep episodes.     

Effect of lithium preparations on cardiac arrhythmias due to strophanthin in waking rats

It was shown in experiments on conscious rats that intravenous injection of strophanthine in toxic doses provokes heart arrhythmias and death of the animals. Lithium drugs (lithium chloride and lithium hydroxybutyrate) injected during arrhythmias led to a short-lived effect of heart rhythm normalization. Lithium hydroxybutyrate was more effective if administered shortly after strophanthine injection, reducing the latter's cardiotoxic effect and preventing the death of the majority of the animals.     

Effects of lithium salts on experimental neurogenic lesions of the stomach and heart

It has been demonstrated in experiments on noninbred rats that lithium chloride and lithium hydroxybutyrate exert a prophylactic therapeutic effect in respect to neurogenic gastric lesions and reduction in the content of creatine phosphate in gastric and cardiac tissues, induced by stressful exposures (3-hour immobilization and electric stimulation of hungry animals). The effects of lithium hydroxybutyrate were more demonstrable than those of lithium chloride.