Electrophysiological Recording from <em>Drosophila</em> Trichoid Sensilla in Response to Odorants of Low Volatility

Abstract

Insects rely on their sense of smell to guide a wide range of behaviors that are critical for their survival, such as food-seeking, predator avoidance, oviposition, and mating. Myriad chemicals of varying volatilities have been identified as natural odorants that activate insect Olfactory Receptor Neurons (ORNs). However, studying the olfactory responses to low-volatility odorants has been hampered by an inability to effectively present such stimuli using conventional odor-delivery methods. Here, we describe a procedure that permits the effective presentation of low-volatility odorants for in vivo Single-Sensillum Recording (SSR). By minimizing the distance between the odor source and the target tissue, this method allows for the application of biologically salient but hitherto inaccessible odorants, including palmitoleic acid, a stimulatory pheromone with a demonstrated effect on ORNs involved in courtship and mating behavior. Our procedure thus affords a new avenue to assay a host of low-volatility odorants for the study of insect olfaction and pheromone communication.

Asymmetric ephaptic inhibition between compartmentalized olfactory receptor neurons

“…A fly was wedged into the narrow end of a truncated plastic 200-μl pipette tip to expose the antenna, which was subsequently stabilized between a tapered glass microcapillary tube and a coverslip covered with double-sided type 54 . Single-unit recordings were performed as follows.…”

“…Ethanol was allowed to evaporate for 1 h in a vacuum desiccator prior to experiments. The odor cartridge was positioned around 4 mm away from the antenna as described 54 . Odor stimulus was delivered via a 500-ms pulse of air (500 ml min −1 ) directly at the antenna in the presence of humidified air flow at 2000 mlmin −1 from a different direction.…”

Distinct Roles and Synergistic Function of FruM Isoforms in Drosophila Olfactory Receptor Neurons

“…Single-sensillum recordings A fly was wedged into the narrow end of a truncated plastic 200 mL pipette tip to expose the antenna, which was then stabilized between a tapered glass microcapillary and a coverslip covered with double-sided type. Single-unit recordings were performed essentially as described (Ng et al, 2017). Briefly, electrical activity of target ORNs was recorded extracellularly by placing a sharp electrode filled with artificial hemolymph solution (Wang et al, 2003) in the at4 sensillum (Or47b ORN recordings).…”

“…The at4 sensillum, which houses the Or47b ORNs (at4A), was identified based on the location of the sensillum on the antenna, sensillum morphology and the number of compartmentalized neurons, as described (Ng et al, 2017). Or67d ORNs are singly-housed in the at1 sensilla, which were similarly identified in addition to their responsiveness to cis-vaccenyl acetate (van der Goes van Naters and Carlson, 2007;Kurtovic et al, 2007;Ha and Smith, 2006).…”

Asymmetric ephaptic inhibition between compartmentalized olfactory receptor neurons

“…200-μl pipette tip to expose the antenna, which was subsequently stabilized between a tapered glass microcapillary tube and a coverslip covered with double-sided type 51 . Single-unit recordings were performed essentially as described 10 .…”