Antagonism of glucagon to effects of morphine and electroacupuncture on the noxiously evoked discharges of dorsal horn neurons in rats

There are reports that glucagon administrated intracerebroventricularly can antagonized morphine analgesia. The experiment was performed on 69 wide dynamic range (WDR) and high threshold(HT) neurons in 53 rats. The results showed that: morphine(5 mg/kg, ip)and EA(2 H_(z), 4-6V, for 30 min)may significantly inhibite the noxiously evoked discharges of WDR and HT neurons to the noxious stimuli on the peripheral receptive fields or sciatic nerves; glucagon pretreatment(10 mug, applied into the dorsal surface of the spinal cord)significantly antagonized morphine and EA inhibitions on the firings of the neurons; futhermore, at 10 and 30 min after morphine administration, glucagon may partly reverse the inhibitory effect induced by morphine, and glucagon treatment alone significantly excited most of WDR and HT neuorn^s activities recorded.