Effects Of5-HT On The Visual Learning And Memory In The Cricket Gryllus Bimaculatus

Objective To probe into effects of serotonin (5-HT) on the initial visualperformance, learning acquisition, and memory retention.Methods we pharmacologically manipulated5-HT levels in the selectedcricket by feeding them drugs(a-methyl tryptophan and5-hydroxy tryptophan) thatact either as a precursor or inhibitor of5-HT metabolism. The drug treatment cricketsconstituted the serotonin enhancing group and serotonin reducing group model animal.Then, these treated crickets followed a visual associative learning memory behavioralexperiments. Based on these experiments, we probed into the effects of serotonin onthe the initial visual performance, learning acquisition, and memory retention. Finally,we performed an immunohistochemical technique to detected the expression of5-HTin the cricket brain, indicated the possible organizational structure where the serotoninassociated with crickets visual learning and memory.Results Serotonin levels change influenced on the cricket initial memoryperformance obviously. In the visual learning and memory experiment, serotoninenhancing group crickets is better than that of blank control group, blank controlgroup is better than that of serotonin lower group, at the aspect of initial visualperformance. But this difference effect had not lasting in the subsequent training. Theeffects of serotonin on the learning acquisition had no effect or not obvious. There areno obvious effects between crickets in the blank control group and crickets in theexperimental groups after learning training. At the last, after24hours of three groupscrickets had learning acquisition, all crickets had a significant difference on memorydeficits, however, still had some memory retention. Further analysis shows that theserotonin enhancing group had no significant difference on the long-term memoryperformance, nevertheless, serotonin reducing group had a significant difference. So itshows that serotonin levels change could not influence memory retention totally.Serotonin levels change not made memory deficits stop or made memory retentionstrong. That is to say5-HT levels had effects on memory retention in crickets, to someextent.5-HT immunohistochemical experiment showed that in crickets5-HT mainly expressed in the protocerebrum and the fan-shaped body of central complex, they hadpositive immune reactions significantly.Conclusion serotonin could be critical for learning and memory performancein an insect.5-HT levels had effects on viral learning and memory performance incricket Gryllus Bimaculatus.