Headley P M, Lodge D, Duggan A W
Brain Res. 1976 Jan 23;101(3):461-78. doi: 10.1016/0006-8993(76)90471-6.
Experiments have been performed on pentobarbitone anesthetized or decerebrated rats. The nature of the synchronous rhythmical activity which occurs in the inferior olive following the electrophoretic or systemic administration of harmaline, harmine, dihydro-beta-erythroidine and various other compounds, is described. Harmine was shown to reduce the late phase of biphasic unitary action potentials and to evoke massed synchronous rhythmical activity on which the units were superimposed. The beta-carboline was more effective than ACh or DL-homocysteate (DLH) in increasing cell discharge rates. Synchronized rhythmical activity was recorded more than 500 mum from the site of ejection of the rhythm-inducing drugs. Developed rhythmical activity reduced the size of antidromic field potentials, but antidromic invasion could reset the rhythm of submaximal rhythmical activity. The effects of ACh and DLH, glycine, GABA, NA, DA and 5-HT were tested on established rhythmical activity. Of these, 5-HT was the only compound which almost invariably antagonized the rhythm. A number of tryptamine derivatives and reported 5-HT antagonists, as well as parachlorophenylalanine, have been tested, but the results were largely inconclusive. The hypothesis is advanced that the drug-induced rhythm results from the inhibition of a tonic inhibitory serotonergic input. This antagonism releases an innate tendency of olivary cells to discharge both rhythmically and synchronously.
实验是在戊巴比妥麻醉或去大脑的大鼠身上进行的。描述了在电泳或全身给予哈马灵、哈尔明碱、二氢-β-刺桐啶和各种其他化合物后，下橄榄核中出现的同步节律性活动的性质。结果表明，哈尔明碱可降低双相单位动作电位的后期，并诱发大量同步节律性活动，单个单位叠加在该活动之上。在增加细胞放电率方面，β-咔啉比乙酰胆碱或DL-高半胱氨酸（DLH）更有效。在距诱发节律药物喷射部位500多微米处记录到了同步节律性活动。发达的节律性活动减小了逆向场电位的大小，但逆向冲动入侵可重置次最大节律性活动的节律。测试了乙酰胆碱、DLH、甘氨酸、γ-氨基丁酸、去甲肾上腺素、多巴胺和5-羟色胺对已建立的节律性活动的影响。其中，5-羟色胺是唯一几乎总是拮抗该节律的化合物。测试了多种色胺衍生物和报道的5-羟色胺拮抗剂以及对氯苯丙氨酸，但结果大多没有定论。有人提出假说，认为药物诱导的节律是由于抑制了紧张性抑制性血清素能输入所致。这种拮抗作用释放了橄榄核细胞有节奏和同步放电的内在倾向。
