Ox-DHE and MDA quantification.

Ox-DHE fluorescent signal was acquired from ChAT-immunoreactive neurons in the DMnX (bregma –7.48 to –7.32 mm), hypoglossal nucleus (–7.48 to –7.32 mm), striatum (+0.26 to +1.10 mm), and medial septal nucleus (+0.26 to +1.10 mm) or from hα-synuclein–immunoreactive DMnX neurons. Using confocal images, neurons were delineated based on ChAT or hα-synuclein immunoreactivity. Ox-DHE puncta within the delineated cells were selected by applying a constant intensity threshold and outlined using the “analyze particles” function. The total integrated density of the outlined puncta was quantified for each image, divided by the number of neurons, and averaged for each animal. For quantification of MDA, brains were removed and snap-frozen on dry ice. Specimens of the dorso-medial medulla oblongata (10 mg wet tissue/animal) were assayed using a Colorimetric MDA Assay Kit (Abcam) according to the manufacturer’s protocol.