5-羟色胺-7受体激动剂对大鼠内侧前额叶皮层锥体神经元电活动的影响

Effect of 5-HT_7 receptor agonist on pyramidal neurons in medial frontal cortex of rats

目的:探讨5-羟色胺-7(5-hydroxytryptamine-7,5-HT7)受体对内侧前额叶皮层(medial prefrontal cortex,mPFC)中锥体神经元电活动的影响。方法:以大鼠为研究对象,采用在体细胞外生物电记录的方法,观察mPFC锥体神经元电活动的变化。结果:静脉给予累积剂量的(40～640μg/kg)5-HT7受体激动剂AS19后,对大鼠mPFC中锥体神经元的电活动产生兴奋、抑制和不变3种不同的影响。无论是体循环,还是mPFC局部微量注射AS19(0.08μg/100 nl),锥体神经元的总体反应都是兴奋的,而体循环给予AS19所引起的抑制效应能够被γ-氨基丁酸A型受体拮抗剂picrotoxinin(2 mg/kg)反转。静脉给予picrotoxinin能兴奋所有记录到的锥体神经元;静脉注射picrotoxinin后,再局部给予AS19能够进一步增加所记录到的神经元的放电频率。结论:mPFC锥体神经元的活动直接或间接地受到5-HT7受体的调控。

Objective：To investigate the activity of medial prefrontal cortex（mPFC） pyramidal neurons in rats and their response to 5-hydroxytryptamine-7（5-HT 7） receptor stimulation.Methods：The change of the spontaneous firing of pyramidal neurons in mPFC was observed by extracellular recording in vivo.Results：In this study,we reported that systemic and local administration of 5-HT 7 receptor agonist AS19 produced excitation,inhibition and no change in the firing rate of pyramidal neurons in mPFC of rats.The mean response of the pyramidal neurons to AS19（0.08 μg / 100 nl） by systemic and local administration in mPFC was excitatory.The inhibitory effect by systemic administration of AS 19 was reversed by γ-aminobutyricacid A receptor antagonist picrotoxinin（2 mg / kg）. Systemic administration of picrotoxinin excited all the neurons examined in rats.After treatment with picrotoxinin,the local administration of AS19 increased the firing rate of the neurons.Conclusion：These results indicate that the activity of mPFC pyramidal neurons is regulated through activation of 5-HT 7 receptor by direct or indirect action.