Neurons with access to the general circulation in the central nervous system of the rat: a retrograde tracing study with fluoro-gold.
Central nervous system neurons which have access to the general circulation were identified by injecting the retrograde tracer Fluoro-Gold peripherally. Fluoro-Gold does not penetrate the blood-brain barrier but is taken up by nerve terminals which project to areas supplied by fenestrated capillaries or to the periphery. Fluoro-Gold-accumulating neurons were present in the following regions or cell groups of the central nervous system: diagonal band of Broca; medial preoptic area; organum vasculosum of the lamina terminalis; subfornical organ; anterior periventricular area; paraventricular nucleus; arcuate nucleus; accessory magnocellular nuclei of the hypothalamus; motor neurons of cranial nerves III-VII, and IX-XII in the brainstem and spinal cord; autonomic ganglionic cells of cranial nerve III (Westphal-Edinger nucleus) in the mesencephalon and the intermediolateral column of the spinal cord; sensory ganglia of the cranial nerve V (mesencephalic trigeminal nucleus); and the C1-C2 and A2 adrenergic cell groups in the medulla. In addition, Fluoro-Gold-accumulating neurons were seen in the sensory ganglia of cranial and spinal nerves. Retrograde labeling with Fluoro-Gold can be combined with immunocytochemistry to identify the chemical messengers within Fluoro-Gold-labeled perikarya. Although a large number of neurons are labeled in the central nervous system with Fluoro-Gold when it is administered peripherally, this technique in combination with immunocytochemistry can be a powerful tool to identify selected neuronal systems in the central nervous system.
Merchenthaler
I
I
Functional Morphology Section, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709.
D000818:Animals; D001370:Axonal Transport; D001812:Blood-Brain Barrier; D001921:Brain / Q000098:blood supply / Q000166:cytology*; D002196:Capillaries / Q000648:ultrastructure; D003391:Cranial Nerves / Q000098:blood supply / Q000166:cytology; D005456:Fluorescent Dyes / Q000493:pharmacokinetics; D005727:Ganglia, Spinal / Q000098:blood supply / Q000166:cytology; D051379:Mice; D009474:Neurons / Q000648:ultrastructure*; D051381:Rats; D013266:Stilbamidines
C049774:2-hydroxy-4,4'-diamidinostilbene, methanesulfonate salt; D005456:Fluorescent Dyes; D013266:Stilbamidines