Cudennec A, Bonvento G, Duverger D, Lacombe P, Seylaz J, MacKenzie E T
Synthélabo Recherche (LERS), Department of Biology, Bagneux, France.
Neuroscience. 1993 Jul;55(2):395-401. doi: 10.1016/0306-4522(93)90508-d.
In the present study, we have investigated the effects of an activation of the ascending serotonergic pathway on the cerebral blood supply to a number (63) of well-defined neuroanatomical structures. To this end, we have measured the local cerebral blood flow during electrical stimulation of the dorsal raphe nucleus. Measurement of regional blood flow was performed in the conscious rat through the use of the [14C]iodoantipyrine autoradiographic technique. Stimulation of the dorsal raphe nucleus induced increases (> 15% compared to control) in cerebral blood flow in 17 structures of which statistical significance (P < 0.05) was achieved in nine; raphe stimulation significantly decreased flow in three regions. The greatest increases (+71 and +46%) were found in the frontal sensorimotor and posterior parietal cortices. Other increases were noted in relay stations of the extrapyramidal and limbic systems. Stimulation induced a decrease in two regions of the primary auditory system and in the lateral habenular nucleus. These results show that activation of the serotonergic pathway in the conscious rat effects regional cerebral blood flow heterogeneously, differing from the widespread increase in glucose utilization that we previously observed using the same experimental paradigm. Statistical analyses indicated that activation of the dorsal raphe nucleus resulted in a global modification of the flow-metabolism ratio. Moreover, in 19 out of 31 regions analysed, this ratio is significantly altered as compared to control. The dichotomy between raphe-induced changes in flow and glucose-metabolism could be explained by one or both of two hypotheses; firstly there could be a direct serotonergic innervation of cerebral resistance vessels; secondly, during raphe stimulation it could be that glucose use is not the primary determinant of tissue perfusion.
在本研究中，我们调查了上行血清素能通路的激活对多个（63个）明确的神经解剖结构的脑血流量的影响。为此，我们在电刺激中缝背核期间测量了局部脑血流量。通过使用[14C]碘安替比林放射自显影技术，在清醒大鼠中进行区域血流量的测量。刺激中缝背核可使17个结构的脑血流量增加（与对照组相比增加>15%），其中9个结构具有统计学意义（P<0.05）；中缝刺激使3个区域的血流量显著降低。额叶感觉运动皮质和顶叶后皮质的血流量增加最为显著（分别增加71%和46%）。在锥体外系和边缘系统的中继站也观察到其他区域血流量增加。刺激导致初级听觉系统的两个区域和外侧缰核的血流量减少。这些结果表明，清醒大鼠血清素能通路的激活对局部脑血流量的影响是不均匀的，这与我们之前使用相同实验范式观察到的葡萄糖利用广泛增加不同。统计分析表明，中缝背核的激活导致血流量-代谢比的整体改变。此外，在分析的31个区域中的19个区域，该比值与对照组相比有显著变化。中缝刺激引起的血流量和葡萄糖代谢变化之间的二分法可以用以下两种假设中的一种或两种来解释：首先，可能存在对脑血管阻力的直接血清素能神经支配；其次，在中缝刺激期间，葡萄糖的利用可能不是组织灌注的主要决定因素。
