| Summary: | 碩士 === 中國醫藥學院 === 中國醫學研究所 === 83 === The possible analgesic mechanisms of electroacupuncture (EAc) in different frequencies were studied by using modified intrathecal catheterization method.
The efficacy of electraoacupuncture analgesia (EAA) in low current (1 mA) are more potent than in high current (2, 3 mA). In addition, high current of EAc stimulation repeatedly may reduce the analgesic effect. Thus, the electric current of 1 mA EAc was chosen to study the mechanism of EAc (2,10 and 100 Hz). The present study was designed to access which subtype of opioid and serotonergic receptors were involved in different frequencies of EAA by the tail-flick test in rats after EAc stimulation at Zu- San-Li. Opioid and serotonergic receptor ligands were administered intrathecally. The results showed that 0.05μg naloxone and naltrindole blocked both low and high frequencies of EAA. The former was more susceptible in low frequency and the latter was susceptible in high frequency of EAc. The effects of EAA in three frequencies were attenuated by pretreatement with 100 μg 5, 7-DHT, implying the serotonergic neuron may participate in the EAA. Furthermore, 0.5,5μg pindobind-5-HT1A could reverse low and high frequencies of EAA; 0.5μg 8-OH-DPAT inhibited the high frequency of EAA but facilitated the low frequency of EAA at doses of 1 and 2μg. Low frequency of EAA was attenuated by 0.5μg ketanserin; 10μg DOI didn''t affect the EAA. 0.5μg LY-278584 attenuated the high frequency of EAA and inhibited the EAA at dose of 5μg. In addition, 50μg 2-methyl-5-HT could enhance the EAA.
These data suggest that the μ-, δ-opioid receptors and 5-HT1A, 5-HT2, 5-HT3 receptors in rat spinal cord are involved in the EAA. The μ- and δ-opioid receptors may play a role mainly in low and high frequency of EAc. However, the exact relationships between EAc and 5-HT subtypes on spinal pre- or post-synapse need
|
|---|
