Koyama Y, Toga T, Kayama Y, Sato A
Department of Physiology, Fukushima Medical College, Japan.
Neurosci Res. 1994 Jul;20(1):79-84. doi: 10.1016/0168-0102(94)90024-8.
The laterodorsal tegmental nucleus (LDT) is the largest aggregation in the brainstem of cholinergic neurons whose axons reach the thalamus as part of a diffuse projection to the forebrain. We measured the regional blood flow in the thalamus by means of laser Doppler flowmetry, and examined whether the blood flow was regulated by the ascending cholinergic nerve fibers originating in the LDT. Experiments were performed on urethane-anesthetized rats whose upper cervical spinal cord was transected to avoid response of systemic blood pressure following LDT stimulation. The ascending cholinergic nerve fibers were excited by electrical or chemical stimulation applied to the LDT. The regional thalamic blood flow increased in response to repetitive electrical stimulation and chemical stimulation with L-glutamate to the LDT. The response, starting several seconds after the onset of electrical stimulation and lasting as long as 1 min, was reduced by i.v. scopolamine, a cholinergic muscarinic receptor antagonist. The results indicate that regional blood flow in the thalamus is increased by excitation of the ascending cholinergic nerve fibers originating in the LDT mainly through the cholinergic muscarinic receptors.
外侧背盖核（LDT）是脑干中胆碱能神经元的最大聚集区，其轴突作为弥散投射到前脑的一部分到达丘脑。我们通过激光多普勒血流仪测量丘脑的局部血流量，并研究血流量是否受源自LDT的胆碱能上行神经纤维调节。实验在经乌拉坦麻醉且上颈段脊髓横断的大鼠身上进行，以避免LDT刺激后全身血压的反应。通过对LDT施加电刺激或化学刺激来激发胆碱能上行神经纤维。对LDT进行重复电刺激和用L-谷氨酸进行化学刺激后，丘脑局部血流量增加。该反应在电刺激开始后几秒开始，持续长达1分钟，静脉注射胆碱能毒蕈碱受体拮抗剂东莨菪碱可使其减弱。结果表明，源自LDT的胆碱能上行神经纤维的兴奋主要通过胆碱能毒蕈碱受体增加丘脑的局部血流量。
