Objective To develop an ultra high performance liquid chromatography-mass spectrometry(UPLC-MS)method for quantifying serum levels of norepinephrine(NE)and 5-hydroxytryptamine(5-HT),and to monitor the dynamic changes in these neurotransmitters during the process of establishing a model of acute reserpine-induced depression-like mice.Methods By evaluating matrix effect,recovery,precision,and accuracy efficiency,an UPLC-MS method for determining the concentrations of NE and 5-HT in serum was established.Forty-eight C57 mice were randomly divided into normal control and model groups,which were intraperitoneally injected with physiological saline(10 mL/kg)and reserpine(2.5 mg/kg),respectively.At various time points after intraperitoneal injection,the degree of ptosis and decreases in body temperature of the mice were observed before orbital blood was sample for the determination of NE and 5-HT levels.Results The concentrations of NE and 5-HT showed good linearity within the range of 15.63 to 2000.00 ng/mL,with R2 values greater than 0.999.The results of methodological validation met the requirements for the analysis of biological samples,with a lower limit of quantification of 15.63 ng/mg.After intraperitoneal injection of reserpine,the model mice exhibited varying body temperature decreases and ptosis.At 1 and 2 h post-administration,the depression-like symptoms in the model group were significantly different from those of the normal control group(P＜0.01).The body temperature of mice in the model group was significantly lower than that of mice in the normal control group(P＜0.01),while the score of the eyelid ptosis was significantly higher(P＜0.001).The levels of NE and 5-HT in the serum of model mice were also significantly depleted,and were significantly different from those of the normal control group at 0.5,1 and 2 h(P＜0.05).Conclusion The study process of established a rapid and accurate method for dynamically observing the changes in NE and 5-HT levels during the process of establishing a model of acute reserpine-induced depression-like mice,which might contribute to the study of the pathogenesis of depression and the development of new antidepressant drugs.

Menthol is the main component of mint volatile oil and a monoterpenoid organic compound. This article systematically summarizes the pharmacological effects， present development and application status of menthol. It is found that menthol can protect the central nervous system through acting on the transient receptor potential （TRP） channel subfamily M member 8， 5-hydroxytryptamine system， γ -aminobutyric acid system， etc. Menthol can regulate body temperature through temperature adjustment， relieving heat stress， and other means. It can play an anti-inflammatory role by regulating the production and release of inflammatory mediators such as prostaglandin E2 and leukotriene B4， and exert anti-inflammatory effects through cellular immune effect mediated by TRP channel. It can play analgesic role by activating classic pain perception targets and enhancing inhibitory synaptic transmission. It can promote transdermal absorption by destroying the stratum corneum. It can exert anti-tumor effects by regulating tumor cell proliferation， apoptosis， and adhesion pathways. Menthol can be used as a medicinal excipient for correcting the taste of drugs； it can also serve as an active ingredient and play an important pharmacological role in the treatment of disease， with potential development value.