Hibberd, Timothy J. Efimov, Andrew Wang, Yue Wu, Mingzheng Travis, Lee Ting, Kaila Lee, Min-Kyu Kim, Joohee Kang, Jiheon Riahi, Mohammad Kyloh, Melinda Zagorodnyuk, Vladimir Hu, Hongzhen Rogers, John A. Spencer, Nick J. V？zquez-Guardado, Abraham 2025-05-07T07:00:23Z 2025-05-07T07:00:23Z 2025-05-07 2025-05 0193-1857 https://pubs.kist.re.kr/handle/201004/152374 Considerable evidence suggests that the gut-brain axis can influence behavior. However, there has been a conspicuous lack of technology to provide targeted wireless activation of the gut-brain axis in conscious freely moving animals. We utilized a miniature fully implantable battery-free device to apply highly controlled optogenetic stimuli to the terminal region of gastrointestinal tract, in conscious freely moving mice. The optical stimulator was implanted and secured on the serosal surface of the distal colon and rectum to characterize the behavioral responses evoked by optogenetic stimulation of axons expressing channelrhodopsin (ChR2) driven by the Trpv1 promoter (Trpv1Cre+ChR2 mice). In freely moving Trpv1Cre+ChR2 mice, trains of blue light pulses to the distal colon and rectum induced increased abdominal grooming and reduced movement. In contrast to stimulation of the gut, trains of stimuli applied to the peritoneal cavity evoked writhing and abdominal contraction. Anterograde labeling from nodose ganglia revealed sparse vagal afferent axons and endings in the proximal and mid colon, with no labeled axons caudal of the mid colon (within 30 mm of the anus). The distal colon and rectum were densely innervated by spinal afferents. The findings demonstrate that wireless optogenetic stimulation of the gut-brain axis can induce specific behavioral patterns in conscious freely moving rodents, using fully implantable battery-free technology. English American Physiological Society Optogenetic activation of the gut-brain axis in freely moving mice using a fully implantable wireless battery-free device Article 10.1152/ajpgi.00330.2024 1 American Journal of Physiology - Gastrointestinal and Liver Physiology, v.328, no.5, pp.G545 - G557 American Journal of Physiology - Gastrointestinal and Liver Physiology 328 5 G545 G557 N scie scopus 001484054400001 Gastroenterology & Hepatology Physiology Gastroenterology & Hepatology Physiology Article battery-free optical stimulator enteric nervous system gut-brain axis implantable wireless devices optogenetics