Temperature and magnetic field effects on the activity of protocerebral neurosecretory neurons and corpora allata in Cerambyx cerdo L. larvae

Vera Nenadovic,D Mircic,Jelica Lazarevic,Zlatko Prolic,Dajana Todorovic,Marija Mrdakovic

doi:10.2298/abs0501019n

Abstract

The effects of constant temperature and an extremely low-frequency magnetic field (ELFMF, 50 Hz and average induction of 20 mT) on the activity of medial protocerebral neurosecretory neurons (A1 and A2) and corpora allata were investigated in Cerambyx cerdo L. larvae after 30 days of exposure. Both constant temperature of 23?C and the ELFMF led to decrease in activity of A1 and A2 neurosecretory neurons and increase in activity of corpora allata compared to the control group (larvae from natural conditions). The changes are more pronounced in A2 than A1 neurons.

Highlights

Neurosecretory neurons in the insect protocerebrum synthesize and release neurohormones in response to various exogenous and endogenous stimuli
Both constant temperature of 23°C and the ELFMF led to decrease in activity of A1 and A2 neurosecretory neurons and increase in activity of corpora allata compared to the control group
Our previous investigations on xylophagous cerambycid larvae have shown that constant temperature leads to changes in neuroendocrine regulation of development and metabolism of carbohydrates, proteins, and amino acids

Summary

Introduction

Neurosecretory neurons in the insect protocerebrum synthesize and release neurohormones in response to various exogenous and endogenous stimuli. Our previous investigations on the role of the neuroendocrine system in response and adaptation to stressful conditions (physical and chemical stressors) in xylophagous insects showed that the response at the level of peptidergic neurons preceded the response at the organism level (Ivanović et al 1975a, 1975b; Ivanović et al 1979; Ivanović et al 1980; Nenadović et al 1982; Janković -Hladni et al 1983; Ivanović et al 1991; Leković et al 2001; Mrdaković et al 2004). The changes provoked by magnetic fields at the level of the neuroendocrine system, especially peptidergic neurons, have been scarcely studied. Such investigations are rare even in vertebrates, where it was shown that a magnetic field influenced the neurosecretory function of the hypothalamus and circadial biorhythms in mice (Zagorskaya , 1981)

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