Apomorphine-induced modulation of neural activities in the ventrolateral striatum of rat

纹状体腹外侧部（Svl）的多巴胺能系统在口面运动的调节中起着重要作用：多巴胺D1样受体和D2样受体的双侧共刺激诱发大鼠重复性下颌运动。然而，它仍然是未知的，如何通过多巴胺能受体的激活调节Svl神经元的活动。在本研究中，我们系统地注射阿扑吗啡（2 mg/kg i. v.），一种非选择性多巴胺受体激动剂，在氨基甲酸乙酯麻醉下诱导下颌运动，并从Svl神经元进行多通道单位记录。根据放电模式，SVl神经元可分为两个亚型：相位活动（PA）和紧张性活动（TA）神经元。阿扑吗啡对SVL PA神经元的趋异作用可能反映了D1和D2受体在中棘神经元的差异表达。阿扑吗啡诱导的TA神经元活动的抑制与减少同步输出可能会减少局部释放的乙酰胆碱，这可能会调节阿扑吗啡诱导的下颌运动。

The dopaminergic system in the ventrolateral portion of striatum(Svl), a part of basal ganglia, plays an important role in the regulation of orofacial movements : bilateral co-stimulation of both dopamine D1-like and D2-like receptors elicits repetitive jaw movements in rats. However, it is still unknown how activities of Svl neurons are modulated by activation of dopaminergic receptors. In the present study, we systematically injected apomorphine(2 mg/kg i. v.), a non-selective dopamine receptor agonist, that induced jaw movements under urethane anesthesia, and performed multi-channel unit recording from Svl neurons. According to the spike firing patterns, the Svl neurons were classified into two subtypes ; phasically active(PA) and tonically active(TA) neurons. The divergent effects of apomorphine on PA neurons in the Svl might reflect differential expression of D1-like and D2-like receptors in the middle spiny neurons. Apomorphine-induced suppression of TA neuron activities with decreased synchronized outputs is likely to reduce locally released acetylcholine, which may modulate apomorphine-induced jaw movements.