Abstract
Dopamine release plays an important role in regulating neuronal behaviors behind drug addiction and abuse. Plant alkaloids and nicotine salts administrations have been reported to exert significant effects on dopamine release in human and animal brains. However, in vivo detection of dopamine in the brain is challenging and mostly invasive, which greatly limit its wide application to study drug-induced neurological mechanisms. A novel 18F- Fallypride positron emission tomography (PET) imaging method was demonstrated for the detection the dopamine secretion in SD rats. The effects of four alkaloids /nicotine salts (nicotine, nicotine benzoate, caffeine and arecoline hydrobromide) on dopamine secretion in SD rats were systematically investigated based on PET imaging using 18F-Fallypride as a marker. The results showed that the effective dopamine saturation dosage of nicotine, nicotine benzoate, caffeine and arecine hydrobromide were 0.125 mg/kg, 0.150 mg/kg, 0.165 mg/kg and 0.300 mg/kg, respectively. Besides, there were also sex differences in the intensity of dopamine secretion of the four alkaloids and nicotine salts under the same dose. Additionally, animal behavior study has supported these pharmacological differences. This work provided a noninvasive real-time detection method to study dopamine excitability by neuronal stimulants in vivo to better understand addiction and abuse ability.