title: Differences in the distribution of cytochrome b561 and synaptophysin in dog splenic nerve: a biochemical and immunocytochemical study.
abstract: Compared with neurons of the CNS, the organization of the peripheral adrenergic axon and nerve terminal is more complex because two types of neurotransmitter-containing vesicles, i.e., large (LDVs) and small dense-core vesicles, coexist with the axonal reticulum (AR) and the well-characterized small synaptic vesicles. The AR, which is still poorly examined, is assumed to play some role in neurosecretion. We have studied the subcellular localization of noradrenaline, cytochrome b561, and synaptophysin in control and ligated dog splenic nerve using both biochemical and ultrastructural approaches. Noradrenaline and cytochrome b561 coaccumulated proximal to a ligation, whereas distally only the latter was found. Despite a codistribution with noradrenaline at high densities in sucrose gradients, synaptophysin did not accumulate on either side of the ligation. At the ultrastructural level, cytochrome b561 immunoreactivity was found on LDVs and AR elements, both accumulating proximal to the ligation. Distally, the multivesicular bodies (MVBs), immunolabeled for cytochrome b561, account for the retrograde transport of LDVs and AR membranes retrieved at the nerve terminal. No synaptophysin immunoreactivity could be detected on LDVs, AR, or MVBs. The results obtained from the ligation experiments together with the ultrastructural data clearly illustrate that synaptophysin is absent from LDVs and AR elements in adrenergic axons.
authors.affiliation: Department of Medicine, University of Antwerp, Belgium.
authors.forename: W G
authors.initials: WG
authors.lastname: Annaert
authors.forename: J
authors.initials: J
authors.lastname: Quatacker
authors.forename: I
authors.initials: I
authors.lastname: Llona
authors.forename: W P
authors.initials: WP
authors.lastname: De Potter
mesh_terms: D000818:Animals; D001370:Axonal Transport; D001369:Axons / Q000737:chemistry / Q000378:metabolism / Q000648:ultrastructure; D003573:Cytochrome b Group / Q000032:analysis / Q000378:metabolism*; D004285:Dogs; D005260:Female; D008297:Male; D016253:Microscopy, Immunoelectron; D009474:Neurons / Q000737:chemistry / Q000378:metabolism* / Q000648:ultrastructure; D009638:Norepinephrine / Q000032:analysis; D013154:Spleen / Q000294:innervation*; D013564:Sympathetic Nervous System / Q000737:chemistry / Q000378:metabolism* / Q000648:ultrastructure; D013572:Synaptic Vesicles / Q000737:chemistry / Q000378:metabolism / Q000648:ultrastructure; D016708:Synaptophysin / Q000032:analysis / Q000378:metabolism*
chemical_list: D003573:Cytochrome b Group; D016708:Synaptophysin; C023646:cytochrome b561; D009638:Norepinephrine