[Experimental study on combined effect of low temperature and vibration on peripheral circulation function and peripheral nerve function].

OBJECTIVE: To study the combined effect of low temperature and vibration on function of peripheral circulation and nerve. METHODS: 64 rabbits were divided into control group, low temperature group, vibration group and combined effect group randomly, 16 each group. The changes of concentration of ET, Ang II, NO in plasma and SCV, amplitude of sensory nerve action potential, latency of sensory nerve action potential, MCV, distal amplitude of motor nerve, and distal latency of motor nerve were measured before and after experiment. RESULTS: After experiment, the concentration of ET, Ang II, NO and SCV, amplitude of sensory nerve action potential, latency of sensory nerve action potential, MCV, distal amplitude of motor nerve, and distal latency of motor nerve were (68.84+/-14.81) pg/ml, (544.01+/-70.20) pg/ml, (123.73+/-9.58) nmol/ml, (25.36+/-6.96) m/s, (1.84+/-0.65) microV, (4.05+/-1.04) m/s, (27.40+/-6.05) m/s, (1.60+/-0.52) microV, (3.51+/-1.30) m/s respectively in low temperature group; (70.22+/-15.02) pg/ml, (540.77+/-68.25) pg/ml, (129.46+/-11.99) nmol/ml, (27.69+/-6.16) m/s, (2.19+/-0.53) microV, (3.86+/-0.89) m/s, (30.03+/-5.21) m/s, (1.65+/-0.49) microV, (3.36+/-l.11) m/s respectively in vibration group; (88.47+/-13.20) pg/ml, (687.38+/-101.44) pg/ml, (70.66+/-4.99) nmol/ml, (20.82+/-3.65) m/s, (1.21+/-0.64) microV, (5.05+/-0.94) m/s, (19.97+/-4.37) m/s, (1.09+/-0.49) microV, (4.49+/-1.26) m/s respectively in combined effect group; compared with pre-experiment, the concentration of ET and Ang II in low temperature group, vibration group and combined effect group were increased after experiment, and the NO was decreased (P<0.05); the nerve conduct velocity and amplitude was decreased and the latency was delayed (P<0.05). After experiment, the concentrations of ET and Ang II in combined effect group were higher than low temperature group and vibration group, and the concentration of NO in combined effect group was lower than low temperature group and vibration group (P<0.05). After experiment, the SCV and MCV in combined effect group were slower than low temperature group and vibration group; the amplitude of sensory nerve action potential and distal amplitude of motor nerve were less than low temperature group and vibration group; the latency of sensory nerve action potential and distal latency of motor nerve in combined effect group was longer than low temperature group and vibration group. The factorial analysis results indicated the synergistic effect between low temperature and vibration (P<0.05). CONCLUSION: Vibration-induced peripheral vascular impairment and nerve impairment would be intensified by low temperature.

[Effects of low temperature on functions of learning, memory and activities of ATPase in brain tissue of mice].

OBJECTIVE: To explore the effects of low temperature on the functions of learning and memory and activities of ATPase in brain tissue of mice. METHODS: 120 mice were randomly divided into 3 groups of A, B, and C with different cold exposure time. After low temperature test, learning and memory ability and activities of ATPase in brain tissue of the mice were measured. RESULTS: Compared with corresponding control group, in the test of learning ability, the total electric shock period [(41.00 +/- 12.06), (45.90 +/- 13.61) min], the total electric times (85.00 +/- 15.81, 89.00 +/- 17.29), and the error reaction times (33.60 +/- 10.69, 39.00 +/- 11.63) were increased in group A and group C significantly (P < 0.01, P < 0.05), but the rate of right reaction (53.60% +/- 11.23%, 54.59% +/- 6.14%) were decreased in group A and group C significantly (P < 0.01, P < 0.05). In the test of memory ability, the total electric shock period [(19.00 +/- 4.62), (51.70 +/- 15.19) min] in group A and group C were increased significantly (P < 0.05, P < 0.01), the rate of right reaction (86.17% +/- 6.34%, 65.92% +/- 8.17%) in group A and group C were decreased significantly (P < 0.05). In test of activities of ATPase in brain tissue, the activities of Na(+)-K(+)-ATPase and activities of Ca(2+)-Mg(2+)-ATPase in brain tissue in group A and group C were decreased significantly (P < 0.05, P < 0.01). CONCLUSION: Low temperature could decrease the functions of learning and memory and the activities of Na+-K+-ATPase and Ca(2+)-Mg(2+)-ATPase in brain tissue of mice.