Essential oils (EOs) are lipophilic secondary metabolites obtained from plants; terpenoids represent the main components of them. A lot of studies showed neurotoxic actions of EOs. In insects, they cause paralysis followed by death. This feature let us consider components of EOs as potential bioinsecticides. The inhibition of acetylcholinesterase (AChE) is the one of the most investigated mechanisms of action in EOs. However, EOs are rather weak inhibitors of AChE. Another proposed mechanism of EO action is a positive allosteric modulation of GABA receptors (GABArs). There are several papers that prove the potentiation of GABA effect on mammalian receptors induced by EOs. In contrast, there is lack of any data concerning the binding of EO components in insects GABArs. In insects, EOs act also via the octopaminergic system. Available data show that EOs can increase the level of both cAMP and calcium in nervous cells. Moreover, some EO components compete with octopamine in binding to its receptor. Electrophysiological experiments performed on Periplaneta americana have shown similarity in the action of EO components and octopamine. This suggests that EOs can modify neuron activity by octopamine receptors. A multitude of potential targets in the insect nervous system makes EO components interesting candidates for bio-insecticides.

Biological effects of extremely low-frequency magnetic field (ELF-MF) and its consequences on human health have become the subject of important and recurrent public debate. ELF-MF evokes cell/organism responses that are characteristic to a general stress reaction, thus it can be regarded as a stress factor. Exposure to ELF-MF “turns on” different intracellular mechanisms into both directions: compensatory or deleterious ones. ELF-MF can provoke morphological and physiological changes in stress-related systems, mainly nervous, hormonal, and immunological ones. This review summarizes the ELF-MF-mediated changes at various levels of the organism organization. Special attention is placed on the review of literature from the last decade. Most studies on ELF-MF effects concentrate on its negative influence, e.g., impairment of behavior towards depressive and anxiety disorders; however, in the last decade there was an increase in the number of research studies showing stimulating impact of ELF-MF on neuroplasticity and neurorehabilitation. In the face of numerous studies on the ELF-MF action, it is necessary to systematize the knowledge for a better understanding of the phenomenon, in order to reduce the risk associated with the exposure to this factor and to recognize the possibility of using it as a therapeutic agent.

During summer land snails are repeatedly exposed to low oxygen tension and to enhanced production of reactive oxygen species due to aestivation/arousal cycles. To test the role of reduced glutathione (GSH – the main endogenous antioxidant) and effect of season on its function we examined activities of glutathione-related enzymes and concentration of GSH in Helix pomatia snails (1) during their natural aestivation/arousal cycle in summer and (2) after their acclimation to different thermal and photoperiod conditions in autumn. Natural aestivation evoked decreases in activity of glutathione reductase (GR) in the hepatopancreas and kidney and an increase in activity of glutathione transferase (GST) in the hepatopancreas, but did not affect activity of glutathione peroxidase (GPX) and concentration of GSH in these organs. Activities of GR in both organs and GST in the kidney were highly affected by acclimation to summer-specific ambient conditions, whereas activity of GPX and GSH concentration were affected by acclimation to 25°C at a short-day photoperiod. In conclusion, H. pomatia maintains relatively high organ concentrations of reduced glutathione but can also modulate its enzymatic antioxidant defence system according to environmental conditions.