We report here on a structural association of single cilia, via their striated rootlets, with the Golgi complex in epithelial cells and stromal fibroblasts of rabbit ciliary processes of the eye. The structure is designated a Golgi-cilium complex and its likely role in aqueous humor production is discussed.

The Golgi complex (1-3, 7) and the single cilium (9, 13, 14) have been studied in various cell types, but less extensively in the ciliary processes (8). The relationship between the cilium and Golgi complex has been neglected (9 for Refs) until recently, when Poole et al.(9) stressed that such association appears to be exclusive to the trans-Golgi face, thus assuming a new functional significance. The present study extends Poole's hypothesis. Rabbits (n= 7) were anaesthetized and specimens were taken from the ciliary processes of the eyes and processed for TEM observation using the routine, glutaraldehyde-Os04, method. Ultrathin sections (uranyl acetate, lead citrate) at different planes of sectioning were examined with a JEM 7A or EM 109 Turbo (Opton) electron microscope. No more than one cilium per cell was observed. Cilia were commonly found in nonpigmented and pigmented epithelial cells (NPEC and PEC, respectively) at their apico-lateral areas (Fig. la) and in ciliary channels. Two cases in which both cilia and the Golgi complex translocated into the basal part of PEC were recorded. A total of 63 ciliary profiles were documented and analyzed (31 in NPEC, 19 in PEC, 4 channelized cilia, 9 in stromal fibroblasts). Most cilia in NPEC (Fig. la) and PEC, but few in fibroblasts (Fig. 1 b), showed a spatial relationship between their basal centriole-emerging rootlets and the Golgi complex. It is possible that through this study we are viewing the Golgi-rootlet association for the first time (Figs. la, c, and d), however, two recent reports have also illustrated this association (see Refs. 10 and 12) although the relationship was not discussed. Rootlets (10, 12 for Refs) have been shown in the ciliary epithelium (8), but these were not associated with the Golgi complex. We consider rootlets a predictive morphological sign of ciliation, ie by examining a" cilium-free", rootlet (s)-containing cell section, one may predict the cell ciliation.