Cocaine-induced vs. behaviour-related alterations of spontaneous and evoked discharge of somatosensory cortical neurons
Cocaine-induced vs. behaviour-related alterations of spontaneous and evoked discharge of somatosensory cortical neurons
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DOI：
10.1111/j.0953-816x.2004.03186.x
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发表时间：
2004-02-01
影响因子：
3.4
通讯作者：
Waterhouse, BD
中科院分区：
文献类型：
--
作者：
Drouin, C;Waterhouse, BD
虽然可卡因的滥用潜力主要源于其增加边缘区多巴胺能传递的能力，但药物对其他单胺神经回路的作用可能有助于可卡因成瘾的发展和维持。先前在麻醉大鼠的细胞外记录揭示了可卡因对初级感觉通路的易化影响，这可能会影响可卡因成瘾发展过程中药物相关刺激的处理。我们进一步分析了可卡因在自由行为大鼠（n = 9）中的这些感觉效应。使用一个阵列的8个微电极长期植入初级体感皮层的颗粒下层，我们记录了40个单和64个多单位的基础活动和他们的反应，以电刺激的胡须垫之前和之后的递增剂量的可卡因（0.25-2毫克/公斤静脉注射）。自发和可卡因诱导的探索与皮质神经元的基础放电升高和抑制他们的短潜伏期的兴奋和兴奋后抑制响应于须垫刺激。除了探索相关的改变，可卡因的管理增强了长潜伏期反弹兴奋引起的须垫刺激。感觉反应的这一部分更不稳定，似乎不传达有关刺激的物理特征的信息，可能参与处理与药物有关的感觉刺激。
While the abuse potential of cocaine stems mainly from its ability to increase dopaminergic transmission in limbic regions, drug actions on other monoamine-innervated circuits may contribute to the development and maintenance of cocaine addiction. Previous extracellular recordings in anaesthetized rats revealed a facilitatory influence of cocaine on primary sensory pathways, which could influence the processing of drug-related stimuli during the development of cocaine addiction. We further analysed these sensory effects of cocaine in freely behaving rats (n = 9). Using an array of eight microelectrodes chronically implanted in infragranular layers of primary somatosensory cortex, we recorded the basal activity of 40 single- and 64 multiunits and their response to electrical stimulation of the whisker pad before and after incremental doses of cocaine (0.25-2 mg/kg i.v.). Both spontaneous and cocaine-induced explorations were associated with elevated basal firing of the cortical neurons and suppression of their short-latency excitation and postexcitatory inhibition in response to the whisker-pad stimulation. In addition to exploration-related alterations, the administration of cocaine enhanced the long-latency rebound excitation induced by the whisker-pad stimulation. This component of the sensory response, which is more labile and does not seem to convey information about the physical characteristics of the stimulus, may participate in the processing of drug-related sensory stimuli.