Effect of different LLLT on pituitrin-induced bradycardia in the rabbit.

The objective of this paper was to observe the effect of low-level combined- or single-laser irradiation on bradycardia produced by pituitrin in rabbits. A combined-laser apparatus was made. A 10.6-microm CO2 laser and a 650-nm semiconductor laser, transmitted by different optical fibers, converged to output and irradiate on the Neiguan (PC6) acupuncture point in rabbits with bradycardia produced by pituitrin. Thirty minutes after the model was set, the heart rates of the combined-laser Neiguan group made quicker recoveries than those of the model control group, the laser-control group, or the single-laser Neiguan group (P<0.05), and the heart rates of the single-CO2-laser Neiguan group were similar to those of the normal group (P>0.05). However, there were significant differences between the 650-nm-laser Neiguan group and the normal control group (P<0.05). The combined-laser irradiation certainly has a curative effect on bradycardia produced by pituitrin. A single CO2 laser could accelerate the recovery from bradycardia, while single 650-nm-laser irradiation on the Neiguan acupoint does not produce such an effect.