Integral part of various neural sensory systems in the antenna that provide the neural basis for the response to environmental changes in temperature (thermosensation) and humidity (hygrosensation) (PubMed:27161501, PubMed:27656904). Together with Ir21a and Ir25a, mediates the response of the larval dorsal organ cool cells, a trio of cool-responsive neurons, to cooling and is required for cool avoidance behavior (PubMed:27656904, PubMed:27161501). Together with Ir25a and Ir40a, mediates the response of the hydrosensory sacculus neurons to changes in relative humidity, and is required for dry detection and humidiy preference behavior (PubMed:27656904, PubMed:27161501). In the antenna, detected in sacculus neurons which innervate the first and second chambers (at protein level) (PubMed:27656904). Expressed in multiple cells of the larval dorsal organ ganglion, including the dorsal organ cool cells where it is predominately localized to the dendritic bulbs (at protein level). Impaired response to environmental cues such as temperature and humidity (PubMed:27161501, PubMed:27656904). Response of dorsal organ cool cells to changes in temperature is abolished and consequently larvae fail to avoid cool temperatures (PubMed:27161501, PubMed:27656904). Response of sacculus neurons to changes in humidity is abolished and consequently larvae fail to move towards their preferred humidity (PubMed:27161501, PubMed:27656904). Belongs to the glutamate-gated ion channel (TC 1.A.10.1) family. Intron retention.