Figure 15.

Induced activity in 5-HTergic neurons and sensory-motor physiology in third-instar larvae. (a1) The segmental nerves of dissected control (UAS-TrpA1) third-instar larvae were stimulated at 40 Hz, 10 pulses, in saline at room temperature. (a2) The saline was exchanged with prewarmed saline in a water bath (37°C) and then applied to the preparation at 32–34°C. (b1) 5-HTergic neurons expressing temperature sensitive cation channel, TrpA1 (Trh-Gal4 (III)>UAS-TrpA1). The evoked activity (EPSPs) of sensory-motor neural circuit was recorded at room temperature (22-23°C) saline. (b2) Saline was switched with prewarmed saline in a water bath (37°C) when the evoked activity was being recorded. Activation of 5-HTergic neurons significantly reduced evoked neural activity. The prewarmed saline was transferred to the dissection dish for both control and TrpA1 expressing third-instar larvae. (c) Activation of 5-HT neurons markedly reduced the number of EPSPs compared to control larvae. Paired t-test was used to compare the frequency of EPSPs inside room temperature saline and prewarmed saline. Student's t-test was used to compare different treatments. Data represented as mean ± SEM.