Effect of desglycine-arginine vasopressin on the excitability of the command neurons of the defensive reflex in the edible snail

Perfusion of the snail (Helix lucorum L.) CNS with DG-AVP (concentration 10(-6) M) in the course of low frequency intracellular stimulation (2-4-minute interval) of the defensive reflex command neurons led to an increase in the excitability. It was expressed both in the reduction of the spike generation latency, in the increased number of spikes in response to fixed stimuli, and in the activation of pacemaker potentials. If DG-AVP was added to the medium during endoneuronal habituation, there was no increase in the excitability. It is supposed that modification of the neuronal excitability may be caused by the DG-AVP effect on the pacemaker mechanism.     

Effect of conditioned-reflex bilateral avoidance learning on lipid components of the rat brain

The active avoidance training of rats resulted in a depletion of lipid peroxidation (LPO) products in cerebral cortex. LPO inhibition was also shown in cerebral cortex of "active control" group receiving +non-combined stimuli (the effect of short-term stress). LPO inhibition was more pronounced in rats staining a training criterion compared to rats which received combined stimuli but did not reach the criterion. In the active control group LPO inhibition was accompanied by total phospholipids accumulation and cholesterol depletion in cortical lipid extracts. Irrespective of attaining the criterion in all rats trained for active avoidance the accumulation of cholesterol was seen. Active avoidance training affected also the phospholipid composition of cerebral cortex.     

Peptide therapy of sleep disorders in neurotic rats

As a result of chronic stress, anxiety appeared in the rats behaviour, motor activity increased, heart rate quickened, blood pressure raised, conditioned instrumental alimentary reflexes missed, the duration of deep phases of sleep lowered, time of falling asleep became longer, the number of awakening increased. The change in quantitative characteristics of sleep was accompanied by its worsening, especially of rapid sleep. Administration of substance P (SP) eledoisin hexopeptide (EH) (250 mcg/kg), 100-200 mcg/kg of delta sleep peptide and 10 mcg/kg of ethylcrotyl barbiturate improved the rats behaviour and sleep parameters. Calipnon accelerated falling asleep. Delta sleep peptide increased sleep duration. SP and EH restored not only the quantitative characteristics of deep phases of sleep but greatly improved their quality: lowered the blood pressure disrupted tachycardia, normalized the conditioned activity.     

The characteristics of higher nervous activity and of the brain benzodiazepine system in rats subjected to ethanol exposure in the prenatal period

Exposure to ethanol during pregnancy results in the alternation of 3H-diazepam binding to synaptosomal neocortical membranes from the rat offspring. In male experimental rats, 14 days of age, binding level diminished to 11%. In two-month-old control rats Scatchard plot was biphasic. It has been shown that prenatal exposure to ethanol leads to changes in the nature of binding in two-month-age experimental animals, as compared with the control ones. 3H-diazepam binding changes went along with behavioural deviations. In experimental rats locomotor activity was increased in the "open field" test, passive avoidance conditioned reflex retention was decreased and elaboration parameters of active avoidance conditioned reflex were changed, as compared with the control ones. The data obtained show that higher integrative functions were disturbed by prenatal alcoholization. Correlations between benzodiazepine receptor state and behaviour were studied.     

Stochastic resonance as a possible mechanism of amplification of weak electric signals in living cells

The most important but still unresolved problem in bioelectromagnetics is the interaction of weak electromagnetic fields (EMFs) with living cells. Thermal and other types of noise pose restrictions in cell detection of weak signals. As a consequence, some extant experimental results that indicate low-intensity field effects cannot be accounted for, and this renders the results themselves questionable. One way out of this dead end is to search for possible mechanisms of signal amplification. In this paper, we discuss a general mechanism in which a weak signal is amplified by system noise itself. This mechanism was discovered several years ago in physics and is known, in its simplest form, as a stochastic resonance. It was shown that signal amplification may exceed a factor of 1000, which renders existing estimations of EMF thresholds highly speculative. The applicability of the stochastic resonance concept to cells is discussed particularly with respect to the possible role of the cell membrane in the amplification process. © 1994 Wiley-Liss, Inc.     

Use of the indirect immunofluorescence test in the diagnosis of an infection, caused by Mycoplasma pneumoniae

The indirect immunofluorescence test has been used for the serodiagnosis of M. pneumoniae infections in two paired blood sera of patients with acute respiratory diseases and acute pneumonia. The optimum methods for obtaining M. pneumonia antigen, its fixation and storage have been determined. The data on the study of the sensitivity, specificity and diagnostic value of the test are presented. The indirect immunofluorescence test has been shown to be capable of the simultaneous detection of complete (complement-binding) and incomplete (not binding the complement) antibodies to M. pneumoniae. This test may be used in the diagnostic practice as a highly sensitive, specific and sufficiently simple serological method.     

The Role of Adipocytes and Adipocyte‐Like Cells in the Severity of COVID‐19 Infections

Coronavirus disease‐2019 (COVID‐19), caused by the highly pathogenic severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2), demonstrates high morbidity and mortality caused by development of a severe acute respiratory syndrome connected with extensive pulmonary fibrosis. In this Perspective, we argue that adipocytes and adipocyte‐like cells, such as pulmonary lipofibroblasts, may play an important role in the pathogenic response to SARS‐CoV‐2. Expression of angiotensin‐converting enzyme 2 (the functional receptor for SARS‐CoV) is upregulated in adipocytes of patients with obesity and diabetes, which turns adipose tissue into a potential target and viral reservoir. This may explain why obesity and diabetes are potential comorbidities for COVID‐19 infections. Similar to the recently established adipocyte‐myofibroblast transition, pulmonary lipofibroblasts located in the alveolar interstitium and closely related to classical adipocytes demonstrate the ability to transdifferentiate into myofibroblasts that play an integral part of pulmonary fibrosis. This may significantly increase the severity of the local response to SARS‐CoV‐2 in the lung. To reduce the severity and mortality associated with COVID‐19, we propose to probe for the clinical response to thiazolidinediones, peroxisome proliferator activated receptor γ agonists that are well‐known antidiabetic drugs. Thiazolidinediones are able to stabilize lipofibroblasts in their “inactive” state, preventing the transition to myofibroblasts and thereby reducing the development of pulmonary fibrosis and stimulating its resolution.