Figure 12.

5-HT and sensory-motor function modulation in third-instar larvae. (a) Dose-response relationship of 5-HT in sensory-motor physiology. 5-HT significantly increased the frequency of EPSPs. The EPSPs of 8 stimulations were recorded for each saline and after exchanging saline with various 5-HT concentrations. (b) Effect of various 5-HT receptor agonists on the frequency of EPSPs in third-instar larvae. Application of 5-HT and 5-HT7 agonist significantly increased the number of EPSPs. The segmental nerve was stimulated at 40 Hz, 10 pulses, and the EPSPs were recorded from muscle fiber 6 or 7. Seven to ten stimulations were analyzed in each saline and after exchanging saline with a saline that contained agonist or in case of the controls fresh saline was used. Paired t-test was used to compare the number of EPSPs in saline and saline that contained an agonist. Data represented as mean ± SEM. P < 0.05 is significant.