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Immunoelectron microscopic study of β‐endorphinergic synaptic innervation of GABAergic neurons in the dorsal raphe nucleus
Author(s) -
Wang QingPing,
Guan JianLian,
Shioda Seiji
Publication year - 2001
Publication title -
synapse
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.809
H-Index - 106
eISSN - 1098-2396
pISSN - 0887-4476
DOI - 10.1002/syn.10008
Subject(s) - dorsal raphe nucleus , glutamate decarboxylase , gabaergic , neuroscience , serotonergic cell groups , raphe nuclei , synapse , nucleus , axon , biocytin , raphe , arcuate nucleus , immunoelectron microscopy , median raphe nucleus , biology , chemistry , central nervous system , serotonin , serotonergic , immunohistochemistry , inhibitory postsynaptic potential , biochemistry , receptor , enzyme , immunology
Using a preembedding double immunoreactive technique by immunostaining with antirat β‐endorphin and antisynthetic glutamic acid decarboxylase antisera sequentially, the synaptic relationships between β‐endorphinergic neuronal fibers and GABAergic neurons in the dorsal raphe nucleus of the rat were examined at the ultrastructural level. Although both β‐endorphin‐like immunoreactive fibers and glutamic acid decarboxylase‐like immunoreactive neurons can be found in the mediodorsal and medioventral parts of the dorsal raphe nucleus, the synapses between them were found only in the mediodorsal part. Most of the β‐endorphin‐like immunoreactive neuronal fibers contained many dense‐cored vesicles. The synapses made by β‐endorphin‐like immunoreactive neuronal axon terminals on glutamic acid decarboxylase‐like immunoreactive neurons were both symmetrical and asymmetrical, with the latter predominant, especially in the axo‐dendritic synapses. Perikarya with β‐endorphin‐like immunoreactivity were found only in the ventrobasal hypothalamus. These findings suggest the possibility that the β‐endorphin‐producing neurons in the ventrobasal hypothalamus could influence GABAergic neurons in the dorsal raphe nucleus directly by synaptic relationships. Synapse 42:234–241, 2001. © 2001 Wiley‐Liss, Inc.