The Relationship between Different Amounts of Physical Exercise, Internal Inhibition, and Drug Craving in Individuals with Substance-Use Disorders

Purpose: To explore the relationship between different amounts of physical exercise and drug craving in individuals with substance-use disorders (SUD), and to reveal the mediating role of internal inhibition between physical activity and drug craving. Method: This study adopted the Physical Activity Rating Scale, Internal Inhibition Scale, and Drug Craving Scale to assess 438 cases of SUD in a compulsory isolation detoxification center in southwest China. Results: (1) The amount of physical exercise individuals with SUD engaged in was positively correlated with internal inhibition and negatively correlated with drug craving, while the amount of physical exercise was negatively correlated with drug craving. (2) The amount of physical exercise was able to negatively predict drug craving in addicts, the amount of physical exercise and internal inhibition were able to jointly predict drug craving, and internal inhibition played a mediating role between the amount of physical exercise and drug craving (the mediating effect was 0.22). (3) There was a dose-effect relationship regarding different amounts of physical exercises and drug craving. Internal inhibition did not mediate between a low amount of physical exercise and drug craving, it played a partial mediating role between a moderate amount of physical exercise and drug craving (the mediating effect was −0.19), and it played a partial mediating role between a high amount of physical exercise and drug craving (the mediating effect was −0.15). Conclusions: Physical activity has a positive effect on reducing drug craving in individuals with SUD. Moreover, in the process of sports rehabilitation for SUD, medium or high amounts of physical activity were required in order to effectively reduce and alleviate drug cravings.

About the rate of differentiation formation depending on the duration of action of the differentiated irritant

It is known that in a positive (delayed) conditioned reflex there is a process of internal inhibition, an indicator of which is the so-called. latency period. Moreover, the more the conditioned reflex is set aside, the more the process of internal inhibition is expressed in it.

Fear signaling in the prelimbic-amygdala circuit: a computational modeling and recording study

The acquisition and expression of conditioned fear depends on prefrontal-amygdala circuits. Auditory fear conditioning increases the tone responses of lateral amygdala neurons, but the increase is transient, lasting only a few hundred milliseconds after tone onset. It was recently reported that that the prelimbic (PL) prefrontal cortex transforms transient lateral amygdala input into a sustained PL output, which could drive fear responses via projections to the lateral division of basal amygdala (BL). To explore the possible mechanisms involved in this transformation, we developed a large-scale biophysical model of the BL-PL network, consisting of 850 conductance-based Hodgkin-Huxley-type cells, calcium-based learning, and neuromodulator effects. The model predicts that sustained firing in PL can be derived from BL-induced release of dopamine and norepinephrine that is maintained by PL-BL interconnections. These predictions were confirmed with physiological recordings from PL neurons during fear conditioning with the selective β-blocker propranolol and by inactivation of BL with muscimol. Our model suggests that PL has a higher bandwidth than BL, due to PL's decreased internal inhibition and lower spiking thresholds. It also suggests that variations in specific microcircuits in the PL-BL interconnection can have a significant impact on the expression of fear, possibly explaining individual variability in fear responses. The human homolog of PL could thus be an effective target for anxiety disorders.

RESTRAIN OF FEAR: PARTICIPATION OF GABA NEUROTRANSMITTER SYSTEM

In experiences on rats in the conditions of free behavior at development of a conditioned of passive avoidanсe reflex (the first series) and a defensive reflex and a conditional inhibition (the second series) it is revealed, and elaboration of internal inhibition and Phenibut – a nonspecific agonist of GAMKA and GAMKB receptors cause in experimental animals weakening of freezing arising in a dangerous situation, and a disinhibition of research behavior. Results of experiences in the accounting of data of the literature allow to assume that both factors, and elaboration of internal inhibition, and Phenibut weaken freezing – the phenomenon used in experiments as a biological analog of fear, owing to increase of level of activity of the GABA neurotransmitter system of a brain. Key words: training, freezing, fear, inhibition, disinhibition, GABA, Phenibut.

Caspase Activity Is Required for Engulfment of Apoptotic Cells

Clearance of apoptotic cells by phagocytic neighbors is crucial for normal development of multicellular organisms. However, how phagocytes discriminate between healthy and dying cells remains poorly understood. We focus on glial phagocytosis of apoptotic neurons during development of theDrosophilacentral nervous system. We identified phosphatidylserine (PS) as a ligand on apoptotic cells for the phagocytic receptor Six Microns Under (SIMU) and report that PS alone is not sufficient for engulfment. Our data reveal that, additionally to PS exposure, caspase activity is required for clearance of apoptotic cells by phagocytes. Here we demonstrate that SIMU recognizes and binds PS on apoptotic cells through its N-terminal EMILIN (EMI), Nimrod 1 (NIM1), and NIM2 repeats, whereas the C-terminal NIM3 and NIM4 repeats control SIMU affinity to PS. Based on the structure-function analysis of SIMU, we discovered a novel mechanism of internal inhibition responsible for differential affinities of SIMU to its ligand which might prevent elimination of living cells exposing PS on their surfaces.