| Summary: | 碩士 === 國立臺灣大學 === 醫學工程學研究所 === 106 === In our lab, we have dedicated to investigate signal transmissions of the touch and nociception for more than two decades. Now, the agent effects on these two signal pathways are needed to be explored. However, since pressure-injection systems commercially available are bulky and expensive, it is hardly possible to construct recording-injection microelectrode with multiple channels at multisite to both record neuronal responses and to deliver agents in the brain of a small animal, such as the rat.
To overcome this challenge, an innovative miniaturized recording-injection microelectrode was constructed in this thesis. The injection system was built by sealing a tapped polyethylene tube, connected with a Hamilton syringe, into one barrel of the microelectrode with super glue, so the proposed electrode can save much operational space in animal experiences. Our results also support that it is reliable to inject quantitative drugs. First, the r-squared of the calibration line between the output volume of the syringe and the really ejected volume reached 0.99. Secondly, the numbers of the evoked action potentials of rat thalamic tactile neurons were decreased proportionally after the injection of two times same amount of ketamine. Besides that, we observed the differential inhibitory effect of ketamine on these neurons and the fluctuations of neuronal activities during the recovery. These phenomena might partially explain the dissociative effect of ketamine and the ketamine-induced hallucination but the further researches are still required to uncovering the underlying mechanism of these interesting situations.
In conclusion, the miniature recording-injection microelectrode was proved to be a reliable tool to conduct more delicate neuropharmacological studies in small animals. After all, the proportional inhibitory local effect of ketamine on rat thalamic tactile neurons was directly demonstrated.
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