Objective: To investigate the functional specificity of acupoint by means of acupoint injection of Dobutamine Hydrochloride (DH).
Methods: Male SD rats were randomized into normal control (NC), EA-Neiguan (PC6) + acupoint injection (AI, EA-PC 6 + AI), EA-Zusanli (ST 36) + AI (EA-ST 36 + AI), and EA-intramuscular injection site (IMIS) + intramuscular injection (EA-IMIS+ IMI) groups,with 8 rats being in each group. EA (2 Hz/15 Hz, 3 mA) was applied to bilateral "Neiguan" (PC 6), "Zusanli "(ST 36) and muscular-injection site for 10 min. DH (a beta1-adrenoceptor agonist) solution (100 microg/kg) was injected intramuscularly into the gluteus maximus after termination of EA intervention. The left ventricular systolic pressure (LVSP), heart rate (HR) and + dp/dt max were recorded before and 2, 5, 15 and 30 min after injection of DH.
Results: The values of LVSP, HR and + dp/dt max in EA-PC 6 + AI group were significantly higher than those in NC, EA-ST 36 + AI, and EA-IMIS + IMI groups (P < 0.01) 2 and 5 minutes after EA plus acupoint injection of DH. No significant differences were found between EA-ST 36 + AI and EA-IMIS+ IMI groups in LVSP, HR and +dp/dt max (P > 0.05). After injection of DH for 30 minutes, the values of LVSP, HR and + dp/dt max in EA-PC 6 + AI group were still significantly higher than those in NC group (P < 0.01).
Conclusion: EA-PC 6+ AI DH is significantly superior to EA-ST 36 + AI DH and EA-IMIS+ IMI DH in producing a stronger cardiac excitatory effect and a longer post-effect, showing a relative specificity of the acupoint in upregulating cardiac functional activities.