Development of an innovative turn-on fluorescent probe for targeted in-vivo detection of nitric oxide in rat brain extracts as a biomarker for migraine disease.

Nitric oxide (NO) is one of the reactive nitrogen species (RNS) that has been proposed to be a key signaling molecule in migraine. Migraine is a neurological disorder that is linked to irregular NO levels, which necessitates precise NO quantification for effective diagnosis and treatment. This work introduces a novel fluorescent probe, 2,3-diaminonaphthelene-1,4-dione (DAND), which was designed and synthesized to selectively detect NO in-vitro and in-vivo as a migraine biomarker. DAND boasts high aqueous solubility, biocompatibility, and facile synthesis, which enable highly selective and sensitive detection of NO under physiological conditions. NO reacts with diamine moieties (recognition sites) of DAND, results in the formation of a highly fluorescent product (DAND-NO) known as 1H-naphtho[2,3-d][1,2,3]triazole-4,9-dione at λem 450 nm. The fluorescence turn-on sensing mechanism operates through an intramolecular charge transfer (ICT) mechanism. To maximize fluorescence signal intensity, parameters including DAND concentration, reaction temperature, reaction time and pH were systematically optimized for sensitive and precise NO determination. The enhanced detection capability (LOD = 0.08 μmol L-1) and high selectivity of the probe make it a promising tool for NO detection in brain tissue homogenates. This demonstrates the potential diagnostic value of the probe for individuals suffering from migraine. Furthermore, this study sheds light on the potential role of zolmitriptan (ZOLM), an antimigraine medication, in modulating NO levels in the brain of rats with nitroglycerin-induced migraine, emphasizing its significant impact on reducing NO levels. The obtained results could have significant implications for understanding how ZOLM affects NO levels and may aid in the development of more targeted and effective migraine treatment strategies.