Experimental paradigm. Cre-dependent hM3Dq was virally administered to either ChAT-Cre or TH-Cre mice. After 3-4 weeks of expression, C21 was injected daily for 10 days to induce specific neuronal activation. Feces was sampled the day prior to the first C21 injection and on days 2, 6, and 10 of C21 administration, and tissue and cecal contents were collected 1 h after the last injection.
