Eun Young Jeong, Collin D Teague, Anisha Reimert, Sungwoo Cho, Juhyun Lee, Thorsten Althoff, Kenneth Lin, Meenakshi Nair, Tess Leong, Emily Silva, Kyle E Parker, Catherine M Cahill, Jordan G McCall, Jae-Woong Jeong, Nicolas Massaly
Studying how drugs act on neuronal circuits requires delivering them with temporal precision while behavior proceeds undisturbed, a combination that tethered infusion systems cannot provide. We developed WEARIT ( W ireless E quipment for A utonomous R at I nfusion T asks), a wearable, tetherless infusion platform that gives freely moving rats intravenous access under either remote or closed-loop operant control. The device houses a reservoir, miniaturized pump, rechargeable battery and Bluetooth circuitry in a 3D-printed enclosure worn on the back. By measuring spontaneous locomotion, amphetamine-induced hyperlocomotion and food-reinforced operant responding, we show that WEARIT leaves these behaviors unchanged. Remotely triggered fentanyl infusions yielded reliable delivery with physiological responses confirmed by pulse oximetry, and self-administration acquisition and dose-response functions were comparable to conventional tethered systems. WEARIT removes a longstanding constraint on intravenous pharmacology, opening self-administration paradigms to naturalistic and enriched environments and to concurrent imaging or optogenetic manipulation of the circuits engaged by drug reinforcement.