an electron microscopic study in the cat has suggested that neurons in the substantia nigra pars reticulata ( snr ) project to the medial reticular formation of the medulla oblongata ( mrf ) via the pedunculopontine tegmental nucleus ( ppn ) : ppn neurons , which were labeled with a retrograde tracer ( wga-hrp ; horseradish peroxidase conjugated to wheat germ agglutinin ) injected into the mrf , were found to be in synaptic contact with axon terminals which were degenerated with neurotoxic agents applied into the snr .
C0078473
wga-hrp
C0019941
horseradish