Uticaj elektromagnetnog polja (2 mT, 50 Hz) na spontanu bioelektričnu aktivnost neurona antenalnog lobusa adulta Morimus funereus (Insecta, Coleoptera)

Abstract

Spoljašnja magnetna polja (MP) narušavaju ravnotežu bioloških sistema, čak i tokom kraćeg vremena izlaganja, što za posledicu ima poremećaje na različitim nivoima organizacije. Na ovaj način nastali poremaćaji akumuliraju se u organizmima, što je jedan od razloga za traženje objašnjenja bioloških efekata MP. S druge strane, veoma važna činjenica koja nas usmerava na što bolje razumevanje ove problematike je potreba za zaštitom ljudskog zdravlja zbog uvođenja novih tehnologija u svakodnevni život, industriju i medicinu, kao i zbog terapijske upotrebe MP. Pretpostavka je da se interakcija spoljašnjih MP i organizama dešava na svim nivoima organizacije, uključujući i nervni sistem. Stoga je cilj ovih istraživanja bio ispitivanje uticaja elektromagnetnog polja (2 mT, 50 Hz) različitih karakteristika (trajanje, talasni oblik) na spontanu bioelektričnu aktivnost neurona antenalnog lobusa adulta Morimus funereus. Aktivnost neurona (pozadinskih/neuronske populacije i najbližih registrujućoj elektrodi) je registrovana kroz nekoliko faza u kojima smo adulte izlagali sinusoidalnom ili kvadratnom MP različitog trajanja: 5, 10 i 15 min (MP-5, MP-10, MP-15, respektivno). Uticaj MP smo procenjivali na osnovu promena u neuronskoj aktivnosti, a procenjivali smo i (i)reverzibilnost promena između tripleta formiranih od određenih eksperimentalnih faza. U tripletima koji slede vremenski tok eksperimenta, a podrazumevaju delovanje MP određenog trajanja (MP-5, MP-10 i MP-15, respektivno), testirali smo i njihove međusobne razlike. Rezultati istraživanja su pokazali da primenjeno MP, bez obzira na dužinu izlaganja i talasni oblik, menja aktivnost neurona antenalnog lobusa. U sinusoidalnom MP, te promene su najizraženije nakon delovanja MP-15, a u kvadratnom MP, nakon delovanja MP-5. Pokazano je da je kontrolna aktivnosti pozadinskih neurona značajno promenjene nakon delovanja sinusoidalnog MP-5, kao i nakon delovanja MP-10, a značajno je manja nakon delovanja MP-15. S druge strane, sinusoidalno MP, bez obzira na dužinu izlaganja izaziva značajnu inhibiciju kontrolne aktivnosti najbližih neurona. Promene kontrolne neuronske aktivnosti su značajno manje nakon delovanja kvadratnog MP različitog trajanja (i MP-5 i MP-10 i MP-15). U odnosu na aktivnost neposredno nakon izlaganja sinusoidalnom MP, povećanje neuronske aktivnosti 35 min nakon izlaganja je za pozadinske neurone značajno u MP-5, a za najbliže neurone u MP-10. Promene neuronske aktivnosti 35 min po prestanku izlaganja kvadratnom MP-5 u odnosu na aktivnost neposredno nakon izlaganja su značajne i kod pozadinskih i kod najbližih neurona. S druge strane, neuronska aktivnost 35 min po prestanku izlaganja kvadratnom MP-10 je kod pozadinskih neurona bila značajno veća, a kod najbližih neurona značajno manja u odnosu na aktivnost neposredno nakon izlaganja. Promene neuronske aktivnosti koje nastaju usled izlaganja sinusoidalnom/kvadratnom MP različitog trajanja, u većini slučajeva su imale ireverzibilan karakter. Sinusoidalno MP različitog trajanja ne izaziva značajne promene faktora reverzibilnosti između tripleta eksperimentalnih faza koji podrazumevaju delovanje MP određenog trajanja. Nasuprot tome, kvadratno MP značajne razlike izaziva kod najbližih neurona i to između tripleta koji uključuju delovanje MP-10 i MP-15. Na osnovu svega navedenog, možemo zaključiti da su jedinke M. funereus osetljive na delovanje i sinusoidalnog i kvadratnog elektromagnetnog polja (2 mT, 50 Hz) različitog trajanja i da njihova reakcija zavisi od karakteristika primenjenog polja, kao i od individualnih specifičnosti jedinki ove vrste. Takođe, naši rezultati ukazuju na činjenicu da M. funereus ima sposobnost da detektuje i odgovara na spoljašnja magnetna polja.

External magnetic fields (MF) disturb the equilibrium of biological systems, even during short-term exposure, resulting in disturbances at different levels of organization. These changes accumulate in organisms, which is one of the reasons for testing biological effects of MF. On the other hand, the fact that modern man is exposed to increasing number of MF sources due to the use of new technologies in everyday life, industry, medicine, as well as therapeutic application of MF, makes this topic even more important, in terms of human health protection. It is assumed that the interaction between external MF and organisms takes place at all levels of organization, including the nervous system. Thus, the aim of this study was to investigate the influence of electromagnetic field (EMF) of different characteristics (exposure duration, waveform) on spontaneous bioelectrical activity of antennal lobe neurons of adult Morimus funereus. Neurons activity (background/neuronal population and those nearest to the recording electrode) was registered through several phases of exposure of adult longhorn beetles to sine wave or square wave MF of different exposure duration: 5, 10 and 15 minutes (MP-5, MP-10 and MP-15, respectively). Estimation of MF influence was based on registered changes of neuronal activity. (I)reversibility of such changes was tested through comparison the triplets formed by particular experimental phases. Changes in triplets that follow the time course of the experiment, with reference to MF influence of different exposure duration (MP-5, MP-10 and MP-15, respectively), were also tested. Results of this study showed that the applied MF, regardless of exposure duration and waveform, modifies the activity of antennal lobe neurons. In sine wave MF, the most prominent changes are recorded after MP-15, while in square wave MF such changes were recorded after MP-5. Control activity of the neuronal population was significantly changed both after MP-5 and MP-10, as well as significantly decreased after MP-15. Sine wave MF, regardless of exposure duration, significantly inhibits control activity of nearest neurons. Changes in control neuronal activity are significantly lower in square wave MF of different exposure duration (MP-5, MP-10, MP-15). Compared to the activity detected immediately after exposure to sine wave MF, the activity of neuronal population and nearest neurons is significantly increased 35 minutes after cessation of MF-5 and MP- 10 exposure, respectively. In case of square wave MF, changes in the activity of neuronal population and nearest neurons are significant 35 minutes after cessation of MF-5 exposure compared to the activity detected immediately after exposure to this MF. On the other hand, the neuronal activity detected 35 minutes after cessation of MF-10 exposure was significantly higher in the neuronal population and significantly lower in the nearest neurons compared to the activity detected immediately after exposure to this square wave MF. Changes in the activity of neurons exposed to sine wave or square wave MF of different duration were mostly irreversible. Sine wave MF of different duration does not change reversibility factors between the triplets formed by particular experimental phases. In contrast, in square wave MF, reversibility factors of the nearest neurons are significantly changed between the triplets formed by MP-10 and MP-15 experimental phase. Results of our experiment imply that M. funereus individuals are sensitive to both sine wave and square wave EMF (2 mT, 50 Hz) of different duration, whereby their reactions depend on the characteristics of the applied MF and specificity of each individual. In addition, it can be presumed that adult M. funereus has the ability to detect and respond to external MF.