I am doing nitric oxide measurement using aorta tissue.I had go through some articles that stated that the tissues were frozen with liquid nitrogen and stored at -80 degree Celsius, then homogenates and continue to assay. Anyone can tell me that if i use the fresh tissues, incubate with drugs, then can i directly homogenates it and continue to the assay instead of store it at -80 degree Celsius before the assay? Thank you very much.