Adams L M, Foote S L
Department of Psychiatry, School of Medicine, University of California, San Diego, La Jolla 92093.
Brain Res Bull. 1988 Sep;21(3):395-400. doi: 10.1016/0361-9230(88)90151-7.
Electrophysiological activity of individual locus coeruleus (LC) neurons was recorded in halothane-anesthetized rats before, during, and after the infusion of adrenergic, cholinergic, or peptidergic compounds about 400 micron lateral to LC. The alpha-adrenergic agonist clonidine (CLON), in concentrations ranging from 5-20 microM (67-270 pg/50 nl injection), reversibly suppressed activity with latencies to onset of 5-15 min and durations of 20-120 min. During the onset of suppressed firing, responses to sensory stimuli (footshock) were relatively preserved, but at later times the reliability of footshock responses was greatly reduced. The alpha-adrenergic antagonist piperoxane (PIP) rapidly reversed the inhibitory effects of CLON. Infusion of 0.1 microliter of 0.02 M acetylcholine (ACh) produced a 3-4 min period of increased LC firing, with a 1 min latency to onset. Larger volumes (0.15 microliter) produced greater increases in firing rate lasting 10-12 min. ACh effects were readily reversed with equimolar doses of scopolamine (SCOP). The effects of 0.02 M ACh were also rapidly reversed by equal volumes of 0.001 M CLON, SCOP and CLON reduced basal firing rates without blocking responses to sensory stimuli. Infusion of the cholinergic agonist carbamyl-beta-choline (carbachol) produced robust, reliable activation of LC neurons at doses of 25-1,000 ng per 100 nl injection. The electrophysiological effects of 3 adrenocorticotropin hormone (ACTH) fragments [1-24], [4-10], and [1-10] were also evaluated. ACTH[1-10] and ACTH[4-10] decreased LC activity for up to 2 hr. ACTH[1-24] exhibited more complex effects, with an increase in discharge rate being accompanied by a decrease in action potential amplitude.(ABSTRACT TRUNCATED AT 250 WORDS)
在氟烷麻醉的大鼠中，于蓝斑（LC）外侧约400微米处输注肾上腺素能、胆碱能或肽能化合物之前、期间及之后，记录单个蓝斑神经元的电生理活动。α-肾上腺素能激动剂可乐定（CLON）浓度范围为5 - 20微摩尔（67 - 270皮克/50纳升注射量），可使活动可逆性抑制，起效潜伏期为5 - 15分钟，持续时间为20 - 120分钟。在放电抑制开始时，对感觉刺激（足部电击）的反应相对保留，但在后期，足部电击反应的可靠性大大降低。α-肾上腺素能拮抗剂哌克昔林（PIP）迅速逆转可乐定的抑制作用。输注0.1微升0.02 M乙酰胆碱（ACh）可使蓝斑放电增加3 - 4分钟，起效潜伏期为1分钟。更大体积（0.15微升）可使放电率更大幅度增加，持续10 - 12分钟。等摩尔剂量的东莨菪碱（SCOP）可迅速逆转乙酰胆碱的作用。0.02 M乙酰胆碱的作用也可被等体积的0.001 M可乐定迅速逆转，可乐定和东莨菪碱降低基础放电率，但不阻断对感觉刺激的反应。胆碱能激动剂氨甲酰 - β - 胆碱（卡巴胆碱）以每100纳升注射25 - 1000纳克的剂量可使蓝斑神经元产生强烈、可靠的激活。还评估了三种促肾上腺皮质激素（ACTH）片段[1 - 24]、[4 - 10]和[1 - 10]的电生理效应。促肾上腺皮质激素[1 - 10]和促肾上腺皮质激素[4 - 10]可使蓝斑活动降低长达2小时。促肾上腺皮质激素[1 - 24]表现出更复杂的效应，放电率增加的同时动作电位幅度降低。（摘要截取自250字）
