Figure 1

Larval dbd neurons generate action potentials and express multiple voltage activated currents. A) Schematic of dbd neuron location in body wall relative to other identified sensory neurons (based on positions detailed in [15]). B) Fluorescently labeled sensory neurons in the body wall of a 1^st instar animal. Dorsal is towards top. Asterisks indicate dbd cell bodies in multiple body wall segments. Scale bar = 20 μm. C) High magnification view of a single dbd neuron. Arrows indicate bipolar dentrites. For comparison, chordotonal sensory cells are shown in bottom left (arrowhead). Scale bar = 10 μm. D) Patch pipette filing single 1^st instar dbd cell with rhodamine dextran (different animal from B and C). Scale bar = 10 μm. E) Whole-cell current clamp recording from in a 1st instar dbd neuron. The cell generates action potentials in response to a 6 pA current step. Arrows indicate onset and offset of current injection. F) Whole-cell voltage clamp recording from a larval dbd. Features characteristic of inactivating (I _A ) and non-inactivating (I _K ) K⁺, channels as well as Na⁺ channels are visible. Asterisks indicate unclamped action currents. G) In the presence of blockers specific for I _A (4-AP, 10 mM), I _K (TEA, 50 mM), Ca²⁺ (Cd, 0.2 mM), and Na⁺ (TTX, 1 μM) channels, all outward and inward currents are abolished. H) Voltage clamp step protocol.