Fig. 1: Histamine-independent irradiance signals.
From: A single photoreceptor splits perception and entrainment by cotransmission
a, Left: schematic of patch-clamp recording from a clock neuron (ITP-LNd); right: representative current (top: voltage clamp) and voltage (bottom: current clamp) responses to light stimuli (470 nm, 2.51 × 107 photons μm−2 s−1, top: 2 ms, bottom: 500 ms). The timing of light stimulation is indicated at the top of the response traces. Genotypes are listed in Supplementary Table 1. b, Histamine-independent responses of clock neurons. Top: representative light responses (470 nm, 2 ms, intensities of 0.01, 0.04, 0.20, 0.41, 0.81, 1.93 and 2.80 × 107 photons μm−2 s−1). WT, wild type. Bottom: pooled saturated response amplitudes. c, Histamine-independent inputs require PLC signalling in compound eyes. Top: schematic of eye input manipulation; middle: representative responses of ITP-LNd in HO flies, norpAP41;;HO flies, HO flies with eyes removed, Rh6-hid,rpr;HO flies and HO flies with HB eyelet axons laser ablated; bottom: pooled saturated response amplitudes. Light: 470 nm, 2 ms, intensities of 0.01, 0.04, 0.20, 0.41, 0.81, 1.93 and 2.80 × 107 photons μm−2 s−1. d, Histamine-independent signals from R8 photoreceptors. Left: schematic of a compound eye with approximately 750 ommatidia, with each ommatidium containing 8 photoreceptors (R1–R8) that express different rhodopsins (Rh1, Rh3–Rh6); middle: histamine-independent responses in norpAP41;;HO mutant flies with norpA rescued in different photoreceptors (with HB eyelet axons laser ablated); right: histamine-independent responses in HO flies with mutations in different rhodopsins (with HB eyelet axons laser ablated). e, R8 photoreceptors do not use histamine to transmit irradiance signals. Top: schematic of photoreceptor signalling; bottom: pooled saturated response amplitudes of R8 photoreceptors of norpAP41 flies with norpA rescued in pR8 or yR8 photoreceptors (with or without HO mutants; with HB eyelet axons laser ablated). Light in d,e: 470 nm, 2 ms, 2.80 × 107 photons μm−2 s−1. Pooled data are shown as mean ± s.e.m. *P < 0.05; **P < 0.01; ***P < 0.001; NS, not significant. Statistical analysis is summarized in Supplementary Table 2.
