N. Fresquet et al., A NEW ATTEMPT TO ASSESS THE EFFECT OF LEARNING-PROCESSES ON THE CHOLINERGIC SYSTEM - STUDIES ON FRUIT-FLIES AND HONEYBEES, Comparative biochemistry and physiology. B. Comparative biochemistry, 119(2), 1998, pp. 349-353
The effect of training on the functioning of the cholinergic system wa
s investigated in fruitflies and in honeybees. Drosophila were submitt
ed to a passive avoidance conditioning of the proboscis extension resp
onse (PER). Flies had to learn to suppress the sugar-induced PER to av
oid an aversive quinine reinforcement. In a yoked control group, the p
unishment was administered with no relation to the response displayed.
Honeybees underwent a five trial olfactory conditioning of the PER el
icited by an antennal gustatory stimulation. In the control group, olf
actory and gustatory stimulations were unpaired to prevent a learning
process from developing. Immediately at the end of the learning sessio
n, acetylcholinesterase (AChE) activity was individually measured on t
he whole animal for Drosophila and on the head for the honeybee in exp
erimental and in control groups. In fruitflies and honeybees, the ACHE
rate did not differ between the experimental group and its respective
control group. Moreover, no significant correlation could be found in
dividually between the learning performance and the ACHE rate in eithe
r Drosophila or in honeybees. This experiment did not reveal any modul
atory effect of the learning acquisition level on the AChE activity in
insects as was previously reported in honeybees (11). (C) 1998 Elsevi
er Science Inc.