Tyrosine-hydroxylase-positive neurons in the substantia nigra pars compacta beside acts of neuronophagia - a process by which microglia (inflammatory cells of the central nervous system) “eat up” the remains of dead neurons. In this case, the culprit is extracellular neuromelanin, an indicator of aging processes and pathological neurodegeneration. The brain slice, 10 microns in width, comes from a patient with Parkinson’s disease. Beside the inflammatory process is a neuron in which one notices a hole within the overwhelming span of neuromelanin in the cytosoplasm. This is probably an alpha-synuclein inclusion, or a Lewy body, a biomarker required for the diagnosis of definite Parkinson’s disease. These inclusions are thought to be toxic species that disrupt normal cellular function and promote the neurodegenerative cascade in vulnerable neurons, although there is MUCH more to the story than misfolded proteins. Notice that the neuron is not immunostained for TH as intensely as the other neurons - this is probably because its cellular functions are disrupted and TH is no longer being synthesized.
Fuck
