Molecular imaging of excitability difference between alkaloids/salts (nicotine, nicotinic benzoate, caffeine and arecoline hydrobromide)

Comparison of the excitability of four different alkaloids/salts, including nicotine, nicotinic benzoate, caffeine and arecoline hydrobromide. Based on positron emission tomography (PET) imaging and ¹⁸F-Fallypride, a novel technique for measuring alkaloid/salt excitability in SD rats was developed. Different doses and types of alkaloids/salts were administered to the SD rats in a single nebulised inhalation.

The results showed that: (1) PET imaging technology can detect the excitability intensity of SD rats after single inhalation of alkaloids/salts in non-invasive real time and the optimal PET scanning time of four different alkaloids/salts (nicotine, nicotinic benzoate, caffeine and arecoline hydrobromide) were slightly different. (2) The excitatory saturation effect of four alkaloids/salts was observed in SD rats after single inhalation and the saturation effect doses of nicotine, nicotine benzoate, caffeine and arecine hydrobromide were 0.063 mg/kg, 0.075 mg/kg, 0.33 mg/kg and 0.075 mg/kg, respectively. (3) In the case of single inhalation of the same dose of four alkaloids/salts, male SD rats inhaled arecoline hydrobromide with the strongest excitability, while female SD rats inhaled nicotinic benzoate. A PET method for noninvasive real-time detection of alkaloid/salt excitability in SD rats was established.

The finding of an excitatory saturation effect for four alkaloids/salts (nicotine, nicotinic benzoate, caffeine and arecoline hydrobromide) and the presence of excitatory intensity and gender differences at the same dose of inhalation of four alkaloids/salts, which provide a new theoretical basis for determiningthe content of alkaloids/salts.