Fung S J, Barnes C D
Arch Ital Biol. 1987 Jul;125(3):187-200.
This study sought to delineate the presynaptic role of the locus coeruleus (LC) on hindlimb primary afferent terminals. Changes in presynaptic function in response to LC stimulation were assessed by measuring the dorsal root potential (DRP), interaction of LC- and peripherally-evoked DRPs, and intraspinal afferent terminal excitability. LC stimulation in unanesthetized, decerebrate cats produced a sequence of early and late positive DRPs succeeded by a small-sized negative DRP. Conditioning the negative DRPs elicited from individual hindlimb nerve branches with LC stimuli led to a decrease in test DRPs. Similarly, there was a predominant decrease in excitability in both large muscle and cutaneous afferent terminals. These data suggest a presynaptic role of the LC in augmenting afferent impulse transmission, presumably through inhibition of tonically active interneurons having axoaxonic contacts on primary afferents; functionally, presynaptic facilitation.
本研究旨在阐明蓝斑（LC）对后肢初级传入终末的突触前作用。通过测量背根电位（DRP）、LC诱发的DRP与外周诱发的DRP之间的相互作用以及脊髓内传入终末兴奋性，评估了对LC刺激的突触前功能变化。在未麻醉、去大脑的猫中，LC刺激产生了一系列早期和晚期正性DRP，随后是一个小的负性DRP。用LC刺激对来自单个后肢神经分支诱发的负性DRP进行条件化，导致测试DRP降低。同样，在大肌肉和皮肤传入终末的兴奋性均有显著降低。这些数据表明，LC在增强传入冲动传递中具有突触前作用，推测是通过抑制在初级传入纤维上具有轴-轴突触联系的紧张性活动中间神经元实现的；在功能上，即突触前易化。
