Intramuscular AAV1-hNT3 caused an elevation of NT3 protein in injected muscles, serum, and ipsilateral cervical dorsal root ganglion cells. ( A ) Quantitative reverse transcriptase PCR showed high levels of human NTF3 mRNA (hNT3) in injected biceps brachii compared to AAV1-GFP rats or shams (Kruskal-Wallis, P = 0.009; Mann-Whitney P = 0.008 and 0.008, respectively, n = 5/group). ( B ) There was no difference between treatment groups in the level of endogenous rat Ntf3 mRNA (Rat NT3) level in the injected muscle (Kruskal-Wallis P -value > 0.05, n = 5/group). ( C ) NT3 protein was significantly elevated in treated triceps brachii in stroke rats at 8 weeks after AAV1-hNT3 administration ( P = 0.018) but not detectably at 4 days ( P = 0.21). ( D ) NT3 was elevated in treated biceps brachii in stroke rats at 8 weeks after AAV-hNT3 administration ( P < 0.001) but not detectably at 4 days ( P = 0.33). ( E ) NT3 increased in the serum at 4 days ( P = 0.039) and 8 weeks after AAV1-hNT3 administration ( P < 0.001). ( F ) NT3 was increased in C2–C6 dorsal root ganglia on the treated side in stroke rats at 4 days ( P = 0.019) and 8 weeks after administration of AAV1-NT3 ( P = 0.031). Mean ± SEM, n = 5/group, t -test versus time-matched GFP control; * P < 0.05, ** P < 0.01, *** P < 0.001.