The transgenic construct contains a tetO (pTRE-Tight) promoter driving expression of a green fluorescent calcium indicator, woodchuck hepatitis virus posttranscriptional regulatory element (WPRE), and a polyadenylation sequence (pA). The GCaMP8s (sensitive) incorporates a hexa-histidine affinity tag, an endothelial nitric oxide synthase peptide (ENOSP; modified with N19T, S24I, and S26M), a circularly permutated green fluorescent protein (cpGFP; modified with Q88E), the rat calcium-binding protein calmodulin (CaM; modified with F286Y and Q315H), and LKI amino acid linkers that replace the RS20 (previously referred to as M13) linkers. (J:101977)