[Evidences of Existence of Serotoninergic Nerves, Enhancing Duodenal Motility].

The review is devoted to the mechanism of duodenal motility activation caused by sympathetic nerves. The authors havefound that stimulation of the sympathetic trunk in the thoracic cavity in dogs in most cases provide not inhibitory but excitatory motor responses of the duodenum. Excitatory effects were eliminated during 5HT-receptors blockade by promedol and lysergol. Analysis ofpublications showed that sympathetic trunk contains serotoninergic fibers, providing excitatory motor responses of the duodenum to electrical nerve stimulation. According to histochemical and physiological studies, amount of serotonergic fibers in the sympathetic trunk is several times more than the adrenergic. This means that the body has sertoninergic nerves. Serotoninergic nerve as well as the sympathetic is a collective notion. There are: sympathetic trunks, their ramifications and branches that innervate the internal organs. Since promedol blocks serotonergic nerves, this is plausible cause of constipation in patients after surgical treatment along with the application of this drug.

[SEROTONERGIC REGULATION OF THE DUODENUM CONTRACTIONS].

The review contains an analysis of literature data on enhancement mechanisms of duodenum contractions arising during stimulation of the sympathetic trunk in the right thoracic cavity in dogs. It is established in experiments that There are mostly enhancement, not relaxation of the organ contraction occured. In this case the stimulatory effect due to the excitation of the parasympathetic fibers is excluded. The trimeperedin inhibit the serotonin receptors of autonomic ganglia neurons stimulatory activity during the nerve stimulation. It is concluded that the sympathetic trunk contain the preganglionic serotonergic nerve fibers, whose activation leads to increased bowel contractions. Direct adipinate-serotonin administration increased the bowel contraction that confirm the preganglionic serotonergic nerve fibers presence in the sympathetic trunk. The practical significance of these studies is that the new approach to the development of pharmacological agents to stimulate the motility of the gastrointestinal tract was found. The trimeperedin may inhibit the serotoninergic nerves activity that resulted in the perioperative constipation in surgical patients. Practical recommendation to exclude trimeperedin in preparing the patient for surgery to prevent perioperative constipation is formulated.

[The significance of different 5-HT-receptors in regulation of gastrointestinal motility].

Serotonergic mechanisms are involved in many, if not all digestive functions of the gastrointestinal tract. A special role is played by serotoninergic structures in the neuronal control of motor activity. The study of these structures is of particular interest due to the widespread occurrence of irritable bowel syndrome, covering up to 20% of the adult population, which makes the research in this area up to date and in demand. Acute experiments were performed on 102 Wistar rats in 6 series. Experiments were carried out under general anesthesia (Nembutal, 60 mg/kg) and mechanical lung ventilation. Motor responses of the stomach, duodenum and ascending colon were studied to i.a. Serotonin adipate infusion (1 mg/kg) during joint blockade of sympathetic and parasympathetic chains of ANS, as well as on the background of the blockade of various 5-HT-receptors. Infusions of 5-HT-blockers reduce the magnitude of motor responses in stomach, duodenum and colon in varying degrees. Based on these data found 5-HT(1b)-receptors are mainly located in enteric neurons. The distribution of 5-HT(2b-4)-receptor is heterogeneous: 5-HT(2b)-receptors are located in enteric neurons of the stomach and intestinal myocytes; 5-HT3-receptors localized in the ganglia supplying the stomach and colon and 5-HT4-receptors are mainly located in the smooth muscle of the stomach, duodenal and ascendent colon enteric neurons.

Study of the nature of sympathetic trunk nerve fibers enhancing gastric motility.

Stimulation of the sympathetic nerve in the thoracic cavity often does not inhibit, but increases stomach contractions in dogs. Blockade of α- and ß-adrenoceptors potentiates this stimulatory effect, while blockade of S(1,2)-receptors localized mainly in smooth muscle cells eliminates it. It is concluded that sympathetic nerve includes serotonergic fibers stimulating gastric motility.

Catecholamines, α-, and ß-adrenoceptors are not responsible for activation of duodenum motility induced by sympathetic nerve stimulation.

Stimulation of sympathetic nerve in anesthetized dogs not treated with adrenergic blockers more frequently exerted stimulating rather than inhibitory effect on duodenal motility. Blockade of α- and ß-adrenoceptors with phentolamine and propranolol, respectively, did not prevent the excitatory action of the sympathetic nerve stimulation, but even potentiated this effect. The data showed that catecholamines as well as α- and ß-adrenoceptors are not involved in the excitatory effect of sympathetic origin.

Chronotropic and inotropic components of cardiac reflexes in cats.

The relationship between chronotropic and inotropic components of cardiac reflexes were studied in cats using intravenous blood injections, occlusion of the abdominal aorta, pressing on eyeballs (Aschner maneuver), and occlusion of the carotid arteries. Inotropic reactions were characterized by the contractility index DPxHR/MSAP. Different reflexes were shown to be characterized by different ratio of chronotropic and inotropic components, in addition, heart rate and contractility were often altered in opposite directions.

[Antibiotic resistance of gramnegative nosocomial pathogens in Minsk ICUs].

The species pattern and antibiotic resistance of gramnegative isolates from patients with nosocomial infections in Minsk ICUs were studied. Pseudomonas aeruginosa, Acinetobacter baumannii, Klebsiella pneumoniae and Escherichia coli were the main pathogens, highly resistant to the antibiotics used. Imipenem, meropenem, polymyxin B, ampicillin/sulbactam, amikacin and cefoperazone/sulbactam were the most active antimicrobials against the isolates. The choice of antimicrobials for empirical therapy of hospital infections in ICUs should be based on the local situation regarding the antibiotic resistance, that makes it obligatory to use regular microbiological monitoring in all hospitals thus providing the policy of the use of antimicrobials in ICUs.

Zero-valent Fe confined mesoporous silica nanocarriers (Fe(0) @ MCM-41) for targeting experimental orthotopic glioma in rats.

Mesoporous silica nanoparticles (MSNs) impregnated with zero-valent Fe (Fe(0) @ MCM-41) represent an attractive nanocarrier system for drug delivery into tumor cells. The major goal of this work was to assess whether MSNs can penetrate the blood-brain barrier in a glioblastoma rat model. Synthesized MSNs nanomaterials were characterized by energy dispersive X-ray spectroscopy, measurements of X-ray diffraction, scanning electron microscopy and Mössbauer spectroscopy. For the detection of the MSNs by MR and for biodistribution studies MSNs were labeled with zero-valent Fe. Subsequent magnetometry and nonlinear-longitudinal-response-M2 (NLR-M2) measurements confirmed the MR negative contrast enhancement properties of the nanoparticles. After incubation of different tumor (C6 glioma, U87 glioma, K562 erythroleukemia, HeLa cervix carcinoma) and normal cells such as fibroblasts and peripheral blood mononuclear cells (PBMCs) MSNs rapidly get internalized into the cytosol. Intracellular residing MSNs result in an enhanced cytotoxicity as Fe(0) @ MCM-41 promote the reactive oxygen species production. MRI and histological studies indicated an accumulation of intravenously injected Fe(0) @ MCM-41 MSNs in orthotopic C6 glioma model. Biodistribution studies with measurements of second harmonic of magnetization demonstrated an increased and dose-dependent retention of MSNs in tumor tissues. Taken together, this study demonstrates that MSNs can enter the blood-brain barrier and accumulate in tumorous tissues.

[Examination of vagus nerve tonus in various animal species]. / Issledovanie tonusa bluzhdaiushchego nerva u zhivotnykh raznykh vidov.

Experiments on pigeons, guinea pigs, rats, cats, rabbits, and dogs showed that tachycardia occurring after ligation of vagus nerves was caused by dissection of their inhibitory tone. They failed to confirm the hypothesis of the sympathetic origin of vagotomic tachycardia. The vagus nerve through the cholinergic neurons may exert heterodirectional (inhibitory and stimulating) effects on the performance of the heart only in animals with its tone. In the absence of tone, there may be only inhibition and stimulation was only short-term as a result of cessation of the inhibitory effect--postvagal tachycardia. The earlier established idea of the inhibitory tone of the vagus nerve remains valid.

[The role of the lipid and phospholipid tissue composition in the synergism of vegetative nervous system parts]. / Rol' lipidnogo i fosfolipidnogo sostava tkanei v sinergizme otdelov vegetativnoi nervnoi sistemy.

The role of the lipid and phospholipid composition of tissue homogenates of the vagus nerve, cervicothoracic ganglion, heart, liver, erythrocytes and blood plasma of rabbits was studied in the synergism of vegetative nervous system parts. It was demonstrated that, when the vagus inhibition of the heart performance increased, the animals used to have a higher concentration of choline-containing phospholipids, and their erythrocyte membranes were more permeable.

[Mechanism of synergism of the sympathetic and parasympathetic nervous system in regulating cardiac and gastric activity]. / Mekhanizm sinergizma simpaticheskoi i parasimatocheskoi nervnoi sistemy v reguliatsii deiatelnosti serdtsa i zheludka.

The authors studied the mechanism of the higher vagus suppression of cardiac performance, which occurs when irritation of the sympathetic nerve is added to that of the vagus and when gastric motility occurring with the irritation of the sympathetic trunk is stimulated. Preganglionic serotonic fibers synaptically connected with serotoninergic intramural neurons are involved in showing these mechanisms.

[Clinico-physiological and biochemical aspects of artificial stable functional connections in the human brain]. / Kliniko-fiziologicheskie i biokhimicheskie aspekty artifitsial'nykh stabil'nykh funktsional'nykh sviazei mozga cheloveka.

The paper presents the results of clinico-physiological and biochemical studies of artificial functional connections (ASFC-1) of the human brain, formed in parkinsonians in the process of treatment by means of implanted electrodes. Medical activation of ASFC-1 is shown to have an optimizing influence on the mechanisms of intracentral regulation and connected with the latter other brain systems, such influence being reflected in the dynamics of clinical effects and vegetative-humoral activities. It is shown that ASFC-1 may be used for treatment and diagnostic aims in patients with prolonged diseases of the nervous system.

[Perceptual-motor activity in children with focal lesions of the brain]. / Osobennosti pertseptivno-motornoi deiatel'nosti u bol'nykh s ochagovymi porazheniiami golovnogo mozga

The pathology of the motor analyser, originating in connection with local lesions of the brain may be studied by means of sensorimotor tracing method. By this parameter, localizations of the lesion produce dissimilar disturbances of the percentive-motor activity. Disorders in movement control were revealed in the case of disturbance of interhemispheric relations resulting from a lesion of the dominant hemisphere; as a result of disfunction of the frontal lobes, which led to disturbance of prognostication; due to disturbance of the "body scheme" and proprioreception disturbances.

[Inhibition of cardiac activity by the stellate ganglion]. / Tormozhenie deiatel'nosti serdtsa zvezdchatym gangliem.

Mechanisms of cardiac activity inhibition in response to the excitation of the stellate ganglion were investigated in acute and chronic experiments involving guinea pigs (43) and rabbits (35). The inhibitory effect was shown to proceed from the excitation of vagal cholinergic fibres that anastomosed with branches of the stellate ganglion, while alpha-adrenoreceptors had no apparent effect on cardiac activity. Neither the hypothesis of preganglionic sympathetic fibres switching to intracardiac cholinergic neurons, nor the one of the cholinergic link in the mechanism of catecholamine release by sympathetic nervous endings was confirmed, therefore the well-known Dale's principle (one neuron produces its efferent effect via one mediator) appears valid here.

[Analysis of the differing mechanisms of action of the vagus nerves on the work of the heart]. / K analizu mekhanizmov raznonapravlennogo vliianiia bluzhdaiushchikh nervov na rabotu serdtsa.

Mechanisms of cardiac acceleration in response to vagal stimulation under some experimental conditions were investigated. The stimulation of one (left or right) or both vagal nerves in pigeons was not shown to produce the acceleration phenomenon either in the presence of atropine effects and stimuli of varying intensity, or with weak and sparse stimulation of intact pigeons.

[Mechanisms of tachycardia caused by administration of atropine and vagotomy in animals of various species]. / Mekhanizm takhikardii, vyzvannoi vvedeniem atropina i vagotomiei, u zhivotnykh raznykh vidov.

Acute experiments on pigeons, rabbits, rats, and guinea pigs demonstrated that the cause of vagotomic tachycardia is exclusion of inhibitory tone of the vagus nerve rather than excitation of the sympathico-adrenal system. With cholinergic neurons, the vagus nerve may accelerate or slow down cardiac rhythm only in animals with marked tone. In its absence, there may be only inhibitory effects, but short-term stimulation is evident, postvagal tachycardia results from cessation of inhibitory effects.

[Mechanism of inhibition of cardiac activity by the stellate ganglion in the cat and guinea pig]. / Mekhanizm tormozheniia deiatel'nosti serdtsa zvezdchatym gangliem u koshek i morskikh svinok.

In acute and chronic experiments on guinea pigs (43) and cats (49), the stellate ganglion inhibition of the heart activity was revealed to be a consequence of excitation of the vagus cholinergic fibers converging with branches of the stellate ganglion on their route to the heart. Alpha-adrenorecptors were shown to exert no noticeable effect on the heart work. Neither the hypothesis of switching of the sympathetic fibers over to intracardiac cholinergic neurons, nor the hypothesis of the cholinergic link in the mechanism of catecholamines release by the sympathetic nerve terminals, were confirmed. The Dayle principle stating that one neuron exerts its efferent affect by means of one transmitter, seems to be justified.