Mraovitch S, Pinard E, Seylaz J
Am J Physiol. 1986 Jul;251(1 Pt 2):H153-63. doi: 10.1152/ajpheart.1986.251.1.H153.
We have studied in anesthetized (alpha-chloralose) and paralyzed (d tubocurarine) rats the effects of electrical stimulation of the fastigial nucleus (FN) on local cerebral blood flow (lCBF) and its relationship to intracerebral PO2, and PCO2 and to the systemic arterial pressure (Pa). Mass spectrometry was used to measure quantitatively lCBF (repetitively) and cerebral PO2 and PCO2 (continuously). A systematic exploration of the FN for an increase in Pa and/or lCBF revealed that the most active sites for the rise in Pa were localized within the rostral FN, while those that elicited an increase in lCBF were found throughout the rostrocaudal extent of the FN. The increase in lCBF elicited from the caudal FN was not associated with changes in Pa. The increase in lCBF was concomitant with an increase in intracerebral PO2 and a slight decrease in PCO2. Although the increases in Pa and lCBF were dependent on stimulus frequency, their frequency-response curves were different. We conclude that 1) in contrast to the neurons or fibers of passage of the rostral FN, which mediate an increase in Pa, the neurons or fibers of passage that elicit changes in lCBF are localized along the rostrocaudal axis of the FN; 2) changes in the local gas partial pressures are not responsible for the vasodilation observed; and 3) the cerebral vasodilation and systemic vasoconstriction evoked by FN stimulation are probably mediated by two different neural mechanisms.
我们在麻醉（α-氯醛糖）且瘫痪（d-筒箭毒碱）的大鼠身上，研究了电刺激小脑顶核（FN）对局部脑血流量（lCBF）的影响，以及它与脑内PO2、PCO2和全身动脉压（Pa）的关系。采用质谱法对lCBF进行定量（重复）测量，并对脑内PO2和PCO2进行连续测量。对FN进行系统性探索以寻找Pa和/或lCBF升高的位点，结果显示，Pa升高的最活跃位点位于FN的吻侧，而引起lCBF增加的位点则在FN的整个前后范围内均有发现。从FN尾侧引发的lCBF增加与Pa的变化无关。lCBF的增加伴随着脑内PO2的增加和PCO2的轻微降低。尽管Pa和lCBF的增加均依赖于刺激频率，但其频率响应曲线不同。我们得出以下结论：1）与介导Pa升高的吻侧FN神经元或纤维通道不同，引起lCBF变化的神经元或纤维通道沿FN的前后轴分布；2）局部气体分压的变化并非观察到的血管舒张的原因；3）FN刺激诱发的脑血管舒张和全身血管收缩可能由两种不同的神经机制介导。
