The European journal of neuroscience
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Vesicular monoamine transporter 2 (VMAT2) packages biogenic amines into large dense core and synaptic vesicles for either somatodendritic or synaptic release from neurons of the CNS. Whilst the distribution of VMAT2 has been well characterized in many catecholaminergic cell groups, its localization amongst C1 adrenergic neurons in the medulla has not been examined in detail. Within the rostral ventrolateral medulla (RVLM), C1 neurons are a group of barosensitive, adrenergic neurons. ⋯ A lentivirus, designed to express green fluorescent protein exclusively in noradrenergic and adrenergic neurons, was injected into the RVLM to label C1 neurons. Eighty-three percent of C1 efferents that occurred in close proximity to sympathetic preganglionic neurons within the T(3) intermediolateral cell column contained VMAT2-immunoreactivity. These data demonstrate differential distribution of VMAT2 within different subpopulations of C1 neurons and suggest that this might reflect differences in somatodendritic vs. synaptic release of catecholamines.
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Intracerebral hemorrhage (ICH) usually affects older humans but almost no experimental studies have assessed aged animals. We address how aging alters inflammation, neuron death and lesion resolution after a hemorrhage in the rat striatum. In the normal aged brain, microglia displayed a 'dystrophic' phenotype, with shorter cellular processes and large gaps between adjacent cells, and there was more astrocyte reactivity. ⋯ At 1 day after ICH, there were fewer activated microglia/macrophages in the aged brain, but by 3 days there were more of these cells at the edge of the hematoma and in the surrounding parenchyma. In both age groups a glial limitans had developed by 3 days, but astrocyte reactivity and the spread of activated microglia/macrophages into the surrounding parenchyma was greater in the aged. These findings have important implications for efforts to reduce secondary injury after ICH and to develop anti-inflammatory therapies to treat ICH in aged humans.