No abstract

The primate Edinger-Westphal nucleus (EW) contains perioculomotor preganglionic (pIII PG ) motoneurons that control the lens and pupil. Separate subdivisions have been described in EW and termed visceral columns, with the lateral visceral column (lvc) reportedly receiving pretectal inputs for the pupillary light reflex. However, choline acetyl transferase staining reveals a single paired column of cells dorsal to the oculomotor nucleus, suggesting the EW is not subdivided. We investigated this issue by transneuronal retrograde labeling of pIII PG neurons in three monkey species. In all three, pIII PG neurons were contained in a single column. We have also examined which part of the macaque pIII PG population receives pretectal input. Injections of biocytin into the pretectum anterogradely labeled terminals that lay in close association with pIII PG motoneurons retrogradely labeled by ciliary ganglion injections of WGA-HRP. These close associations were concentrated in the ventromedial portion of the middle third of EW , suggesting this pIII PG region mediates pupillary control. In other cases, pretectal WGA-HRP injections, in addition to labeling terminals in the EW, produced a circular field of labeled neurons and terminals in the periaqueductal gray, dorsolateral to EW. This region may represent the previously designated lvc, but it does not contain pIII PG motoneurons.

No abstract

Ciliary ganglia from the pigeon, cat, and monkey were investigated for the presence of NADPH-diaphorase reactivity by use of a standard histochemical method. In the pigeon, where the ganglion is known to control lens and pupil function, and the choroidal vasculature, about one-third of the ganglion cells were densely stained and most other somata were lightly stained. In some cases, preganglionic terminals with a cap-like morphology were also darkly stained. The pattern of NADPH-diaphorase staining in mammals was very different from that seen in pigeons. In both mammalian species, where the ganglion is known to control lens and pupil function, a small number (less than 2%) of the ganglion cells were shown to be densely NADPH-diaphorase positive, revealing their neuronal processes. The presence of NADPH-diaphorase positive cells in pigeon, cat, and monkey ciliary ganglia suggests that nitric oxide may be used for intercellular communication in this ganglion, or in light of the known importance of nitric oxide in vascular control, some of these positive neurons may participate in the control of choroidal vasodilation.