Barmack N H, Fagerson M, Errico P
Department of Ophthalmology, R.S. Dow Neurological Sciences Institute, Good Samaritan Hospital & Medical Center, Portland, Oregon 97209.
J Comp Neurol. 1993 Feb 8;328(2):263-81. doi: 10.1002/cne.903280208.
The inferior olive is divided into several subnuclei that receive specific sensory information. The caudal dorsal cap of the medial accessory subdivision of the inferior olive receives horizontal optokinetic information from the nucleus of the optic tract. The immediately subjacent beta-nucleus receives vertical vestibular information mediated by a GABAergic pathway originating from the ipsilateral descending and medial vestibular nuclei. None of the transmitters to the dorsal cap have been identified. Using choline acetyltransferase (ChAT) immunohistochemistry, we have identified a cholinergic pathway that terminates exclusively in the dorsal cap of rats and monkeys. No other division of the inferior olive received a significant cholinergic innervation. In the rabbit, immunostaining for ChAT reveals a weaker and more diffuse cholinergic innervation of both the dorsal cap and the subjacent beta-nucleus. In rats and rabbits we injected iontophoretically the orthograde tracer Phaseolus vulgaris leucoagglutinin (PHA-L) into the medial and descending vestibular nuclei (MVN, DVN) as well as the nucleus prepositus hypoglossi (NPH) in order to trace the possible origin of the cholinergic projection. PHA-L injections into the NPH and medial aspect of the MVN labeled terminals within the contralateral dorsal cap. PHA-L injections in the central and lateral aspects of the MVN as well as the DVN labeled the ipsilateral beta-nucleus. Pressure injections of wheat germ agglutinin-horseradish peroxidase (WGA-HRP) in the caudal dorsal cap of the rabbit inferior olive demonstrated a predominantly contralateral projection to the dorsal cap from the lateral aspect of the NPH. However, pressure injections of HRP into the caudal dorsal cap combined with ChAT immunohistochemistry in the rabbit demonstrated that most of the neurons of the NPH that projected to the dorsal cap were not cholinergic, and that most of the ChAT-positive neurons within the NPH occupied a more ventral location than the neurons within the NPH that were retrogradely labeled from the HRP injection into the contralateral dorsal cap. In the rat, we made lesions in the MVN, DVN and NPH by injection of ibotenic acid (0.3-0.5 microliter), in an attempt to deplete the dorsal cap of the inferior olive of its cholinergic input. Lesions confined to the NPH and medial aspect of the MVN of the rat caused a loss of ChAT staining in the contralateral dorsal cap. Lesions placed more laterally within the MVN or DVN failed to deplete ChAT-positive terminals in the contralateral or ipsilateral dorsal caps. The dorsal cap of the rat and monkey receives a discrete cholinergic projection.(ABSTRACT TRUNCATED AT 400 WORDS)
下橄榄核分为几个亚核，它们接收特定的感觉信息。下橄榄核内侧副核的尾侧背帽接收来自视束核的水平视动信息。紧接其下方的β核接收由源自同侧下行前庭核和内侧前庭核的GABA能通路介导的垂直前庭信息。目前尚未确定投射到背帽的递质。利用胆碱乙酰转移酶（ChAT）免疫组织化学方法，我们确定了一条仅终止于大鼠和猴背帽的胆碱能通路。下橄榄核的其他部分未接受明显的胆碱能神经支配。在兔中，ChAT免疫染色显示背帽及其下方的β核有较弱且更弥散的胆碱能神经支配。在大鼠和兔中，我们通过离子导入法将顺行示踪剂菜豆凝集素（PHA-L）注入内侧前庭核、下行前庭核以及舌下前置核，以追踪胆碱能投射的可能起源。将PHA-L注入舌下前置核和内侧前庭核内侧可标记对侧背帽内的终末。将PHA-L注入内侧前庭核中央和外侧以及下行前庭核可标记同侧β核。向兔下橄榄核尾侧背帽压力注射小麦胚凝集素-辣根过氧化物酶（WGA-HRP）显示，舌下前置核外侧主要向背帽发出对侧投射。然而，向兔下橄榄核尾侧背帽压力注射HRP并结合ChAT免疫组织化学显示，投射到背帽的舌下前置核中的大多数神经元不是胆碱能的，并且舌下前置核内大多数ChAT阳性神经元比从HRP注射到对侧背帽逆行标记的舌下前置核内的神经元位置更靠腹侧。在大鼠中，我们通过注射鹅膏蕈氨酸（0.3 - 0.5微升）损毁内侧前庭核、下行前庭核和舌下前置核，试图耗尽下橄榄核背帽的胆碱能输入。局限于大鼠舌下前置核和内侧前庭核内侧的损伤导致对侧背帽ChAT染色缺失。在内侧前庭核或下行前庭核更外侧的损伤未能耗尽对侧或同侧背帽中的ChAT阳性终末。大鼠和猴的背帽接受离散的胆碱能投射。（摘要截短至400字）
