Acupuncture on the Blood Flow of Various Organs Measured Simultaneously by Colored Microspheres in Rats

We examined how acupuncture affected the blood flow of muscle, kidney, stomach, small intestine, brain, lung, heart, spleen and liver. Wistar rats anesthetized with urethane (n= 27) were allocated into the control (n= 10), ST-7 (Hsia-Kuan,n= 10) and LI-4 (Hoku,n= 7) groups. To measure organ blood flow, colored microspheres (CMS) were injected through a catheter positioned in the left ventricle and blood samples were drawn from the femoral artery. Yellow CMS (3.6–4.2 × 105) and blue CMS (6.0–6.9 × 105) were injected at intervals of about 30 min. An acupuncture needle (φ 340 μm) was inserted into the left ST-7 point (left masseter muscle) or the right LI-4 point after the first sampling and left for about 30 min (10 twists at 1 Hz, 2-min intervals). The mean blood flow of nine organs varied widely from 4.03 to 0.20 (ml/min/g). Acupuncture to the ST-7 produced significant changes of the blood flow (percentage change from baseline) in the muscle, kidney, brain and heart (P< 0.05, versus control), but those of LI-4 were not significant. The blood flow of the left masseter muscle after acupuncture to ST-7 (left masseter muscle) tended to increase (P= 0.08). Changes in blood pressure during the experimental periods were almost similar among these three groups. Acupuncture stimulation increases the blood flow of several organs by modulating the central circulatory systems, and the effects differed with sites of stimulation.

Pancreatic islet blood flow in conscious rats during hyperglycemia and hypoglycemia

Anesthesia affects general hemodynamics and regulation of organ perfusion. We used colored microspheres to measure pancreatic islet blood flow in conscious rats at two time points, during either hyperglycemia or hypoglycemia. This method, using black and green microspheres, was validated by comparison with previous microsphere experiments and by lack of effect of a nonmetabolizable glucose analog, 3- O-methylglucose, on islet perfusion. Basal and glucose-stimulated islet blood flow levels were similar in pentobarbital sodium-anesthetized and conscious rats. However, the basal distribution of pancreatic blood flow was altered by anesthesia (fractional islet blood flow 5.8 ± 0.4% in conscious rats, 7.9 ± 0.8% in pentobarbital-anesthetized rats, P < 0.05). Insulin-induced hypoglycemia significantly increased whole pancreatic blood flow in conscious rats, whereas islet blood flow remained unchanged and fractional islet blood flow was decreased (5.8 ± 0.5% in the basal state, 4.2 ± 0.4% during hypoglycemia, P < 0.001). Methylatropine pretreatment significantly increased islet blood flow during hypoglycemia by 181%. This result suggests that prevention of hypoglycemia-induced increase in islet perfusion may be mediated, at least in part, by a cholinergic, vagal muscarinic mechanism.