CONDITIONED REFLEX MECHANISMS OF ADAPTATION TO ADDITIONAL BREATHING RESISTANCE

The problem of adaptation to additional breathing resistance has recently become more urgent due to the growth of bronchopulmonary diseases. Therefore, there is a natural interest in non-drug strategies compensating resistive breathing in humans. The aim of the study was to assess conditioned reflex changes in the functional state of the subjects under additional breathing resistance. Materials and Methods. The work was carried out on 55 practically healthy subjects of both sexes, aged 18–36. Additional breathing resistance was modeled by inspiratory resistive loads of 40, 60, 70, and 80 % of the maximum intraoral pressure. The conditioned respiratory reflex to resistive respiratory load was developed as a short-delayed conditioned signal with a 30-second period of isolated action. The authors examined behavioral, vegetative, gas and energy indicators of the organism before and after the formation of a conditioned reflex. Results. It was observed that conditioned reflex shifts of physiological parameters in the process of adaptation to additional breathing resistance differ significantly from the corresponding unconditioned reflex changes both in nature and in intensity. Conditioned reflex mechanisms reduce the intensity of shifts in the motor component of the external respiration system, which, apparently, is the main reason to decrease the aversive behavior. Conclusion. Behavioral changes after the formation of a conditioned respiratory reflex to additional respiratory resistance are characterized by a decrease in aversive behavior patterns. The conditioned reflex realization of increasing resistive loads is expressed in a lower physiological cost of adaptation to additional respiratory resistance relative to the unconditioned reflex type of realization. Keywords: adaptation, conditioned respiratory reflex, additional breathing resistance. Проблема приспособления к дополнительному респираторному сопротивлению в последнее время становится все более актуальной в связи с ростом бронхолегочных заболеваний. Поэтому естественен интерес к нелекарственным механизмам компенсации резистивного дыхания человека. Целью исследования являлась оценка условно-рефлекторных изменений функционального состояния испытуемых в условиях дополнительного респираторного сопротивления. Материалы и методы. Работа проведена на 55 практически здоровых испытуемых обоего пола в возрасте от 18 до 36 лет. Дополнительное респираторное сопротивление моделировалось инспираторными резистивными нагрузками величиной 40, 60, 70 и 80 % от максимального внутриротового давления. Условный дыхательный рефлекс на резистивные дыхательные нагрузки вырабатывался по типу короткоотставленного с периодом изолированного действия условного сигнала 30 с. Исследовались поведенческие, вегетативные, газовые и энергетические показатели организма до и после формирования условного рефлекса. Результаты. Показано, что условно-рефлекторные сдвиги физиологических показателей в процессе приспособления к дополнительному респираторному сопротивлению существенно отличаются от соответствующих безусловно-рефлекторных изменений как по характеру, так и по интенсивности. Условно-рефлекторные механизмы уменьшают интенсивность сдвигов моторного компонента системы внешнего дыхания, что, по-видимому, является основной причиной снижения вероятности появления аверсивного поведения. Выводы. Поведенческие изменения после формирования условного дыхательного рефлекса на дополнительное респираторное сопротивление характеризуются снижением вероятности появления аверсивных форм поведения. Условно-рефлекторная реализация возрастающих по интенсивности резистивных нагрузок выражается в меньшей физиологической стоимости приспособления к дополнительному респираторному сопротивлению относительно безусловно-рефлекторного типа реализации. Ключевые слова: приспособление, условный дыхательный рефлекс, дополнительное респираторное сопротивление.

Influence of multiple deficiency of vitamins, calcium, magnesium and iodine on cognitive function in growing rats

Due to the prevalence of multiple deficiency of vitamins and some minerals among the population, as well as the role of micronutrients in maintaining cognitive functions, the aim of the research was to study the effect of combined deficit of vitamins and/or calcium, magnesium and iodine in the diet of growing Wistar male weaning rats on the manifestation of an unconditioned reflex and ability to learn in response to an electric shock. Mice for the experiment were obtained from Stolbovaya nursery, Federal State Budgetory Scientific Institution Scientific Center of Biomedical Technologies of the Federal Medical-Biological Agency (Moscow region, Russia). After a 5-day feeding on a complete semi-synthetic diet, rats with an initial body weight of 51.4 ± 0.5 g were randomly (according to body weight and the results of the “Elevated Plus Maze” test) divided into four groups (10-12 animals in each group). Subsequently, within 23 days, the animals of the control group (I) received a complete semi-synthetic diet, the rats of Group II (- Ca, Mg, I) were fed on the same diet, but with a 50% reduction in the amount of calcium, magnesium and iodine in the mineral mixture, the rats of Group III (- Vit) received a diet containing 100% of minerals with a reduced amount of vitamin mixture up to 20% with the complete elimination of vitamin E from it. The animals of Group IV (- Vit, Ca, Mg, I) were kept on a diet simultaneously deficient in vitamins and mineral substances. The manifestation of the unconditioned reflex was studied in the “Elevated plus maze” test before feeding the animals on experimental diets and on the 21st day of feeding. The behavior and memory of animals were evaluated in the test “Conditioned reflex of passive avoidance” on the 7th day of feeding on experimental diets in response to electrocutaneous irritation of paws (current 0.4 mA, not more than 8 sec.) when entering the dark compartment (development of a conditioned reflex), on the 8th day - a test of training (a memorable trace), and on the 21st day - an assessment of longterm memory. Pre-anesthetized with ether, the rats were taken out of the experiment by decapitation, and the content of vitamin E (α-tocopherol) was determined by HPLC, vitamins B1 and B2 were measured fluorimetrically in the whole lyophilized brain. In this research, we revealed, that throughout the experiment, the general condition of all animals (appearance and fur) and the body weight did not differ. Reducing the content of vitamins in the diet led to a significant decrease (p < 0.001) in the brain content of selectively measured vitamins B1 and E at the end of the experiment (See Table 1), that indicated the development of micronutrient deficiency in them. Micronutrient deficiencies for 21 days did not affect the degree of anxiety of the growing rats, assessed in the “Elevated Plus Maze” test. However, the rats from the groups deficient in vitamins (group - Vit and group - Vit, Ca, Mg and I) had a higher motor activity than the animals of the control group and the animals fed on a diet deficient in calcium, magnesium and iodine (group - Ca, Mg and I), which significantly less moved through the maze (See Table 2). In this research, we found out that on the 7th day of the development of micronutrient deficiency in rats the reproduction of the unconditioned reflex (photophobia) worsened (See Fig. 1). In the rats with vitamin deficiency (group - Vit), the time spent in the open compartments increased 3.0 times compared to the control, whereas in the rats with mineral deficiency (group - Ca, Mg and I) and combined deficiency (group - Vit, Ca, Mg and I) it increased 1.85 and 1.95 times, correspondingly (p < 0.05), while no differences were detected when playing a conditioned reflex 24 hours after training (See Fig. 1). In this research, a significant (p < 0.05) decrease in long-term memory have been discovered in the animals fed on a vitamin-deficient diet (group - Vit) and in the rats fed on a diet with simultaneously reduced levels of vitamins, calcium, magnesium and iodine (group - Vit, Ca, Mg and I). On the basis of the latent time of entry into the dark compartment after 24 hours and 2 weeks, we established that the memory deterioration was due to a decrease in the vitamin content in the diet, whereas the deficit of mineral substances did not affect these parameters (See Fig. 2). In this research, we revealed that multivitamin deficiency in rats exerted an amnestic effect and made a major contribution to impaired learning and long-term memory. This findings suggest the importance of adequate provision of the organism with all vitamins and mineral substances to maintain cognitive functions and memory.

Comparative estimation of anticonvulsant activity of cumarines umbelliferone, obtusifole and Haplofillum obtusifolium grass decoction

Obtusifole and umbelliferone had low toxicity after enteral administration. Even high obtusifole doses demonstrated weak anticonvulsant activity in the models of maximal electroshock (MES) and pentamethylentetrasole seizures (LD 100). These coumarines were not effective in the models of strychnine- and thiosemycarboside-induced convulsions. They revealed neurotoxical influence, reducing unconditioned reflex, normal adoptive mice behavior and did not prevent the loss of conditioned passive avoiding reflex (CPAR) after MES. These coumarines did not antagonize with synthetic anticonvulsants. The Haplophyllum obtusifolium grass decoction administered enterally was not toxic, because LD minimal might not be fixed. It had no neurotoxical properties, prevented the loss of CPAR and mortality after MES, elevated tolerance to convulsive-mortal pentamethylentetrasole and strychnine action. So this decoction demonstrated cerebroprotective properties. The use of Haplophyllum obtusifolium in traditional medicines of Asiatic states may not be explained by only coumarines. It is based on cerebroprotective properties of this medicine.