AIM To investigate the differences of
metoclopramide (MCP) action on
myoelectric activity of
antrum and small
intestine. METHODS Ten healthy male Wistar rats, weighing 250g～350g, were anesthetized with ketamine hydrochloride (100
mg/kg, intramuscularly). Four pairs of bipolar stainless steel electrodes 3mm apart were implanted on serosal surface of antrum and 1, 10 and 20cm distal to pylorus respectively. Five to 10 days after operation, the gastrointestinal
Myoelectric activity of fasted rats after intramuscular injection of 2 5, 6 and 12mg/kg MCP respectively ws recorded with a 8 channel EEG machine, and was quantitatively compared with the myoelectric activity after saline injection. RESULTS In fasted rats, 2 5mg/kg MCP increased the amplitude of
spike activity (402 0μV±138 4μV, vs 345 0μV±163 4μV, P <0 05) and the percentage of the slow wave containing spike bursts (60 4%±22 0% vs 47 4%±22 5%, P <0 01) of small intestine (1cm distal to pylorus), but did not affect the myoelectric activity of antrum. Six and 12mg/kg MCP increased the amplitude of both the slow wave (332 8μV±200 1μV vs 191 2μV±143 9μV, P <0 01; 330 0μV±197 1μV vs 191 2μV±143 9μV, P <0 05) and the spike activity (180 5μV±69 7μV vs 121 8μV±63 3μV, P <0 05; 174 5μV±71 7μV vs 123 8μV±63 3μV, P <0 05) of antrum, while in small intestine (1cm distal to pylorus) only that of the amplitude of spike activity (407 3μV±179 0μV vs 345 0μV±163 4μV, P <0 05; 456 0μV±145 4μV vs 345 0μV±163 4μV, P <0 05) and the percentage of the slow wave containing spike bursts (61 7%±26 5% vs 47 4%±22 5%, P <0 01; 59 1%±17 3% vs 47 4%±22 5%, P <0 01) was increased and with latent period significantly prolonged (2 5min±0 35min vs 0 77min±0 18min, P <0 01). CONCLUSION Different mechanisms may be involved in increasing the myoelectric activity of antrum and small intestine after MCP administration.
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