Background:Amperometric nitric oxide probes are critical in evaluating real-time nitric oxide levels. This valuable tool enables one to measure spontaneous baseline levels of nitric oxide as well as ‘puffs’ of the gaseous signal molecule that may last for only seconds to minutes. However, in the past, many probes suffered from a lack of sensitivity, durability and reliability, causing investigators to design numerous controls to support their data.Material/Methods: Our laboratory evaluated the new ISO-NOPF100 NO probe manufactured by World Precision Instruments of Sarasota, Florida. An invertebrate in vivo heart preparation was used, which presents a high degree of difficulty in obtaining nitric oxide measurements due to space limitations, resulting in physical contact of the probe with tissues. Additionally, we used in vitro invertebrate ganglionic preparations as a comparison since this tissue releases spontaneous and low levels of NO.Results: Calibration of the new probe demonstrated high linearity and sensitivity. The detection limit for this new probe was determined to be approximately two times lower than probes previously used in our laboratory. Basal nitric oxide fluctuations in Mytilus edulis heart and excised ganglia were able to be resolved in the sub-nanomolar range.Conclusions: The ISO-NOPF100 NO probe represents a significant advancement for measuring nitric oxide in real-time.

Keywords: Bivalvia - physiology, Ganglia, Invertebrate - physiology, Heart - innervation, Molecular Probes, Myocardium - metabolism, Nitric Oxide - metabolism, Penicillamine - analogs & derivatives, Penicillamine - chemistry, Bivalvia - physiology, Ganglia, Invertebrate - physiology, Heart - innervation, Molecular Probes, Myocardium - metabolism, Nitric Oxide - metabolism, Penicillamine - chemistry