To investigate the effects of adipose tissuederived stem cells (ADSCs) modified with penile neuronal nitric oxide synthase (PnNOS) gene on intracellular calcium concentration in rat corpus cavernosum smooth muscle cells (CCSMCs).ADSCs and CCSMCs of Sprague Dawley (SD) rat were isolated and cultured in vitro, respectively.Rat PnNOS gene were transferred into ADSCs mediated by recombinant adenovirus vector.The expression of PnNOS gene was detected.At the same time, the concentration of nitric oxide (NO) and cyclic guanosine monophosphate (cGMP) were assayed.After co-culturing with CCSMCs of SD rats which were isolated and expanded ex vivo, the cGMP and NO levels of ADSCs and CCSMCs were measured.Intracellular calcium concentration ([Ca]i)in rat CCSMCs was measured with Fluo-3/AM by flow cytometer after co-cultured with ADSCs over-expressing PnNOS gene.The mRNA and protein expression of PnNOS gene mediated by recombinant adenovirus vector significantly over-expressed and lasted at least 2 weeks.Meanwhile, the concentration of NO and cGMP in ADSCs were greatly elevated.The concentration of cGMP was significantly increased and [Ca]I was obviously decreased in CCSMCs compared with the control groups (P<0.05)after co-cultured with ADSCs for 3 days.These findings demonstrated that ADSCs over-expressing PnNOS gene might decrease [Ca]I in CCSMCs by up-regulating NO-cGMP signaling pathway.