Determination of monoamine neurotransmitters in serum of pain model rats

Abstract

Objective: To investigate the effect of pain on contents of monoamine neurotransmitters in serum of pain model rats.Methods: The model was established by subcutaneous injection of 5% formaldehyde at the sole of left hind limb and the animal behavior was observed and recorded.Contents of norepinephrine(NE) and dopamine in serum of normal and model rats were determined by fluorescence spectrophotometry.The excitation emission wavelength of NE was 384 nm/483 nm,and that of dopamine was 324/373 nm.Results: The linear response of NE ranged from 0.01-0.25 μg/ml(r=0.996 5,n=7),that of dopamine ranged from 0.01-0.20 μg/ml(r=0.993 5,n=7).Intra-day and inter-day RSD of both NE and dopamine were less than 20%.The relative recovery rates of NE and dopamine were 99.8%-113.5% and 99.4%-106.0%,respectively.The contents of NE and dopamine in serum of rats in control group were(0.088±0.030),(0.047±0.005) μg/ml,and those of the rats in model group were(0.122±0.010),(0.064±0.010) μg/ml,respectively.Conclusion: Fluorescence spectrophotometry is accurate and sensitive for the determination of NE and dopamine in serum of rats.Subcutaneous injection of formaldehyde engenders symptoms of pain and probably raises the contents of NE and dopamine in serum of pain model rats.