| BackgroundElectroconvulsive therapy (ECT) is a treatment that has been used for over 75 years, which can be traced back until the 1930s and was initially developed as a medical treatment in 1950s. Due to the unceasing innovation and adaptation to the rapidly changed psychiatric environment, now ECT has involved into a modern medical therapy. Compared with antipsychotic drugs, ECT has the advantages of high effectiveness, safety, low cost and less adverse reactions for severe psychiatric disorders. Recently, ECS is used beyond the field of clinical psychiatric treatment. However, little is known about the mechanisms of therapeutic action of ECT. Electroceronvulsive seizure (ECS) is an animal model of ECT, so it is very necessary and a hot issue to discuss the relevant mechanism of ECS.Objectivesto study the the pathogenesis of mental illness and provide theoretical basis for underlying mechanisms of therapy effect of ECS, we elucidate the effects of single and repeated ECS on the activity of dopaminergic (DA), serotonin (5-HT), acetylcholine (Ach) and gamma-aminobutyric acid (GABA) neurons by investigating the expression levels of tyrosine hydroxylase (TH) protein in the substantia nigra, tryptophan hydroxylase (TPH) protein in the raphe nucleus, acetylcholine transferase (ChAT) protein in the prefrontal cortex and glutamate decarboxylase (GAD-65) in the hippocampus of SD rats after ECS.Methods1.Thirty two healthy adult male Sprague-Dawley (SD) rats with age of 2-3 months and weight of 275-305 g were randomly divided into 4 groups (n=8):control group, single ECS group, repeated ECS group and sham ECS group. Animals were housed four individuals per cage. Control group received no treatment. Single ECS group was offered a single stimulation. Repeated ECS group was given a repeated seizure-inducing electrical stimulus (ECS parameters:100 Hz pulse frequency; 0.5 ms pulse width; 0.7s duration; 75 mA current), one time daily over 2 weeks for a total of 14 times. Sham ECS group was identically handled, and had ear clip electrodes applied but received no charge, one ECS per day for 14 consecutive days to get a total of 14 ECS. In 24 hours following either single or repeated ECS, immunofluorescence techniques were used to assay the expression levels of TH protein in prefrontal cortex, TPH protein in substantia nigra, ChAT protein in raphe nucleus and GAD-65 protein in hippocampus, respectively.2.The all results were presented with means+standard deviations.According to date feature,chose statistical methods such as one-way analysis of variance(ANOVA),LSD test and so on, and the size of a test was a=0.05.SPSS 20.0 system was used for date analysis.Results1. The effect of ECS on the expression level of TH protein in the substantia nigra: Compared with the control group, there was no statistically significant difference (P>0.05) in TH-positive neuron numbers and TH-mean density values for single ECS group, while repeated ECS group showed a significant increase (P<0.05) in TH-positive neuron numbers and TH-mean density values. Compared with the sham ECS group, the animals of single ECS group showed no significant difference (P>0.05) in TH-positive neuron numbers and TH-mean density values. However, TH-positive neuron numbers and TH-mean density values were found a significant increase (P<0.05) in repeated ECS group. There was no significant difference (P>0.05) in TH-positive neuron numbers and TH-mean density values between control group and sham ECS group.2. The effect of ECS on the expression level of TPH protein in the raphe nucleus: Compared with the control group, there was no statistically significant difference (P>0.05) in TPH-positive neuron numbers and TPH-mean density values for single ECS group, while repeated ECS group showed a significant increase (P<0.05) in TPH-positive neuron numbers and TPH-mean density values. Compared with the sham ECS group, the animals of single ECS group showed no significant difference (P>0.05) in TPH-positive neuron numbers and TPH-mean density values. However, TPH-positive neuron numbers and TPH-mean density values were found a significant increase (P<0.05) in repeated ECS group. There was no significant difference (P>0.05) in TPH-positive neuron numbers and TPH-mean density values between control group and sham ECS group.3. The effect of ECS on the expression level of ChAT protein in the prefrontal cortex: Compared with the control group, the significant decrease (P<0.05) in ChAT-positive neuron numbers and ChAT-mean density values was observed in group of single ECS, whereas repeated ECS group showed a significant increase (P<0.05) in ChAT-positive neuron numbers and ChAT-mean density values. Compared with the sham ECS group, the animals of single ECS group also showed a significant decrease (P<0.05) in ChAT-positive neuron numbers and ChAT-mean density values. However, a significant increase (P<0.05) in ChAT-positive neuron numbers and ChAT-mean density values were found in group of repeated ECS. There was no significant difference (P>0.05) in ChAT-positive neuron numbers and ChAT-mean density values between control group and sham ECS group.4. The effect of ECS on the expression level of GAD-65 protein in the hippocampus: Compared with the control group, the significant decrease (P<0.05) in GAD-65-positive neuron numbers and GAD-65-mean density values was observed in group of single ECS, whereas repeated ECS group showed a significant increase (P<0.05) in GAD-65-positive neuron numbers and GAD-65-mean density values. Compared with the sham ECS group, the animals of single ECS group also showed a significant decrease (P<0.05) in GAD-65-positive neuron numbers and GAD-65-mean density values. However, a significant increase (P<0.05) in GAD-65-positive neuron numbers and GAD-65-mean density values were found in group of repeated ECS. There was no significant difference (P>0.05) in GAD-65-positive neuron numbers and GAD-65-mean density values between control group and sham ECS group.Conclusions1. Single ECS had no effect on the activity of DA neurons in the substantia nigra and 5-HT neurons in the raphe nucleus of rat, single ECS decreased the activity of Ach neurons in the prefrontal cortex and GABA neurons in the hippocampus of rat.2. Repeated ECS increased the activity of DA neurons in the substantia nigra and 5-HT neurons in the raphe nucleus of rat, repeated ECS increased the activity of Ach neurons in the prefrontal cortex and GABA neurons in the hippocampus of rat. |
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