Positive interaction between ASH and ASK sensory neurons accelerates nociception and inhibits behavioral adaptation

Central and peripheral sensory neurons tightly regulate nociception and avoidance behavior. The peripheral modulation of nociception provides more veridical and instantaneous information for animals to achieve rapid, more fine-tuned and concentrated behavioral responses. In this study, we find that positive interaction between ASH and ASK sensory neurons is essential for the fast-rising phase of ASH Ca(2+) responses to noxious copper ions and inhibits the adaption of avoiding Cu(2+). We reveal the underlying neuronal circuit mechanism. ASK accelerates the ASH Ca(2+) responses by transferring cGMP through gap junctions. ASH excites ASK via a disinhibitory neuronal circuit composed of ASH, AIA, and ASK. Avoidance adaptation depends on the slope rate of the rising phase of ASH Ca(2+) responses. Thus, in addition to amplitude, sensory kinetics is significant for sensations and behaviors, especially for sensory and behavioral adaptations.