Busija D W
Am J Physiol. 1986 Mar;250(3 Pt 2):H498-502. doi: 10.1152/ajpheart.1986.250.3.H498.
The purposes of this study were to 1) determine the effects of unilateral and bilateral sympathetic stimulation on cerebral blood flow (CBF) during normocapnia and 2) explore the mechanism by which bilateral effects are greater than unilateral effects. In anesthesized rabbits, CBF (15-microns microspheres) and internal carotid artery blood flow (ICBF) were determined during a prestimulation period and electrical stimulation of one or both superior cervical ganglia (8 or 16 Hz, 10 V, 2 ms). Resting CBF ranged from 26 to 34 ml X min-1 X 100 g-1. Unilateral stimulation did not reduce CBF at 8 Hz, but stimulation at 16 Hz reduced ipsilateral blood flow to the cerebrum by 21 +/- 5% (n = 6 from each group). In contrast, bilateral stimulation reduced blood flow to cerebrum by 22 +/- 5 and 40 +/- 4% at 8 and 16 Hz, respectively (P less than 0.05, unilateral vs. bilateral; n = 6 for each group). Similarly, unilateral stimulation at 8 Hz did not reduce ipsilateral ICBF or affect contralateral ICBF. However, bilateral stimulation at 8 Hz reduced ICBF by 51 +/- 6% on both sides. We conclude that 1) bilateral effects of sympathetic nerves on CBF are greater than unilateral effects, and 2) this difference in response may be due to activation of two overlapping sets of sympathetic nerves and release of more neurotransmitter during bilateral sympathetic stimulation.
1）确定在正常碳酸血症期间单侧和双侧交感神经刺激对脑血流量（CBF）的影响；2）探究双侧效应大于单侧效应的机制。在麻醉的兔子中，在刺激前阶段以及对一侧或双侧颈上神经节进行电刺激（8或16Hz，10V，2ms）期间，测定CBF（15微米微球）和颈内动脉血流量（ICBF）。静息CBF范围为26至34ml·min⁻¹·100g⁻¹。8Hz的单侧刺激未降低CBF，但16Hz的刺激使大脑同侧血流量减少21±5%（每组n = 6）。相比之下，双侧刺激在8Hz和16Hz时分别使大脑血流量减少22±5%和40±4%（P < 0.05，单侧与双侧比较；每组n = 6）。同样，8Hz的单侧刺激未降低同侧ICBF或影响对侧ICBF。然而，8Hz的双侧刺激使两侧ICBF均减少51±6%。我们得出结论：1）交感神经对CBF的双侧效应大于单侧效应；2）这种反应差异可能是由于两组重叠的交感神经被激活以及双侧交感神经刺激期间释放了更多神经递质。
