RESUMEN
OBJECTIVE: To observe the effects of electroacupuncture (EA) at acupoints with different nerve segments on gastric emptying in oxytocin (OT) gene knockout mice, and to explore the role of paraventricular nucleus OT in EA regulating gastric function. METHODS: Twenty OT knockout mice and twenty wild-type mice (8-9 weeks old, male and female in half) were divided into a control group, a Zusanli (ST 36) group, a Neiguan (PC 6) group and a Weishu (BL 21) group randomly, 5 mice in each group. The mice in the control group received no acupuncture; the mice in the Zusanli (ST 36) group, Neiguan (PC 6) group and Weishu (BL 21) group were treated with EA at unilateral "Zusanli" (ST 36), "Neiguan" (PC 6) and "Weishu" (BL 21) for 15 min respectively. Subsequently, the mice were treated with intragastric administration with milk loaded with technetium-99m diethylene triamine pentaacetic acid (99mTc-DTPA), immediately followed by scanning of single photon emission computed tomography (SPECT) to test gastric emptying for 50 min; the original data was collected and analyzed to obtain the half gastric emptying time (GET 1/2), 50-min stomach residue rate and gastric emptying curve. RESULTS: The wild-type mice group:compare with the control group, after EA at "Zusanli" (ST 36) and "Neiguan" (PC 6), the GET 1/2 and 50-min stomach residue rate were significantly reduced, which could improve the gastric emptying of wild-type mice (P<0.01, P<0.05); after EA at "Weishu" (BL 21), the GET 1/2 and 50-min stomach residue rate were significantly increased, which could inhibit the gastric emptying of wild-type mice (P<0.01, P<0.05). The OT gene knockout mice group:compared with the control group, EA at "Zusanli" (ST 36) and "Neiguan" (PC 6) had no significant effects on gastric emptying (both P>0.05); after EA at "Weishu" (BL 21), the GET 1/2 and 50-min stomach residue rate were significantly increased, which could inhibit the gastric emptying of OT gene knockout mice (both P<0.01). Gastric emptying curve:the gastric emptying of OT gene knockout mice was significantly faster than that of wild-type mice. CONCLUSIONS: The effects of EA at acupoints with different nerve segments on gastric emptying in mice are different, and the knockout of OT gene could accelerate the gastric emptying, and influence the acupuncture effect of several acupoints. It is suggested the paraventricular nucleus OT neurons, as the initiating device of autonomic nervous pathways, might participate in EA regulating the gastric function to inhibit the gastric emptying, with the form of neural and neuroendocrine.