Chronic morphine exposure induces degradation of receptive field properties of LGN cells in cats

• 来源期刊: 中国药理学报（英文版）
• 关键词: direction sensitivity orientation sensitivity signal-to-noise ratio spontaneous response evoked response
• 年，卷（期）: 2005,（9）
• 页码范围: 1034-1038
• 页数: 5页
• 语种: 英文

摘要

Aim: To investigate the effect of chronic morphine exposure on the receptive field properties of lateral geniculate nucleus (LGN) neurons in cats. Methods: Cats were injected with morphine (10 mg/kg) or saline twice daily, for 10 d. Subsequently,extracellular single-unit recording techniques were used to examine the sensitivity of LGN neurons to visual stimuli in chronic morphine-treated and saline-treated cats. Results: Compared with saline-treated cats (as controls), LGN neurons in morphine-treated cats had decreased signal-to-noise ratios (1.9 vs 3.1), and orientation and direction sensitivity (0.103 vs 0.135 and 0.074 vs 0.10, respectively),accompanied by significant increases in spontaneous (27.4 vs 17.5) and evoked activity (preferred: 42.2 vs 38.1; average: 28.1 vs 22.3). Conclusion: Chronic morphine exposure can lead to the functional degradation of LGN neurons in cats,which might result from the effects of chronic morphine exposure on inhibitory neurotransmission.