A new approach for aggregation of Paramecium caudatum by nitric oxide

Background and Objective: Nitric oxide (NO) plays a role in thermoregulation and growth of protozoa. This work aimed to add the molecule NO in physiology of protozoa in contact with abused narcotic substances. Materials and Methods: A sedative drug, morphine, was infused into a cell chamber containing Paramecia. The cell response to the drug was recorded promptly after drug infusion using a potency protocol provided for the first time at this laboratory. A precursor of NO, L-arginine, was treated jointly with drug to involve the NO system in protozoan performance to drug exposure. Marking of NADPH-diaphorase (NADPH-d) was followed to provide data to explain the mechanisms. Results: Morphine, particularly 0.5 to 60 μg/μl, aggregated the Paramecia. The infusion of L-arginine (1 to 8 μg/μl) together with morphine potentiated this effect, though, pre-usage of L-NAME (1 to 8 μg/μl), a blocker of NO production, reversed the response. Notably the activation of NADPH-d in solely morphine or L-arginine plus morphine samples was revealed. However, the expression of marker was attenuated upon pre-infusion with L-NAME. Conclusion: This study introduces a new approach to involve NO in physiology of aggregation of Paramecia following exposure to the misused sedative drug, morphine.