Figure 8.
Plasticity requires endocytosis in ensheathing glia but not astrocytes. A, We expressed temperature-sensitive dynamin (shibirets) in ensheathing glia (depicted as cells surrounding each glomerulus). Antennae were removed and responses were recorded from antennal projection neurons while applying odors to the palps. Experiments were performed under four conditions: adult flies were cultured at either the permissive (25°C) or the restrictive (30°C) temperature, and antennae were removed either acutely or chronically. B, Chronic antennal removal potentiates odor responses in deafferented projection neurons at permissive temperature but not at restrictive temperature. Inset shows spontaneous activity on a compressed time scale. C, Average membrane potential change in response to five odors under four experimental conditions. The difference between acute and chronic is significant at permissive but not at restrictive temperature (p < 0.05, two-way ANOVA, p < 0.05, post hoc Tukey HSD, n = 10, 11, 10, and 15 for 25°C acute, 25°C chronic, 30°C acute, and 30°C chronic). D, We now expressed shibirets in astrocytic glia (depicted as branching within the glomerulus). Antennae were removed and responses were recorded from antennal projection neurons while applying odors to the palps. Adult flies were cultured at the restrictive temperature (30°C) and antennae were removed either acutely or chronically. E, Odor responses are potentiated after chronic removal of antennae even at the restrictive temperature. F, Average membrane potential change in response to five odors. Odor-evoked depolarization is significantly larger after chronic removal of antennae (p < 0.05, two-way ANOVA, n = 10 and 9 for acute and chronic).