No abstract

Primary ciliary muscle cell cultures derived from human donors (16-9 1 years) were established and characterized by comparing them with ciliary muscle in tissue sections using immunocytochemical and ultrastructural methods. Monoclonal antibodies against desmin, vimentin, a-actinin, smooth muscle (sm) specific a-actin and von Willebrand factor were used. In tissue sections of the ciliary body, ciliary muscle cells, vascular muscle cells, pericytes, endothelial cells and fibroblasts stain for vimentin. Both types of muscle cells and the pericytes stain for cr-sm-actin, but only ciliary muscle cells stain for desmin. For tissue cultures, explants of the meridional and partly the reticular portion of the ciliary muscle were dissected and grown directly or after digestion of the explant with collagenase. Ten primary cell cultures with a typical hill-and-valley growth pattern similar to smooth muscle cells and two with a growth pattern similar to fibroblasts were established. All cultures could be subcultured up to the fifth passage. In fibroblast-like cultures S-10% of the cells stained for z-sm-actin. Staining for desmin was not observed. In smooth muscle-like cultures, all cells stained positive for a-sm-actin. Desmin staining was not seen in growing non-confluent smooth muscle-like cultures. In confluent cultures, about 10% of the cells stained positive for desmin, preferentially in areas where the cells had formed hills. No culture stained for von Willebrand factor. Staining for a-actinin in smooth muscle-like cultures showed that the dense bands of the myofilaments were arranged in register, similar to the typical ciliary muscle cell morphology seen in tissue sections. Ultrastructurally, the smooth muscle-like cultures showed the typical morphology of cultured smooth muscle cells. We conclude that the smooth muscle-like cultures consist of ciliary muscle cells.

No abstract

Bovine outflow tissue differs markedly from that of humans. Tissue culture studies on the cells of this region are often compared with those of primate trabecular meshwork cells. A thorough cytological and immunocytochemical characterization of the cells of the bovine chamber angle is lacking. We have therefore investigated the cells of the pectinate ligament, the reticular meshwork, the region adjacent to the aqueous plexus, the connective tissue region between reticular meshwork and ciliary muscle and the ciliary muscle itself, ultrastructurally and immunocytochemically with staining for the cytoskeletal proteins vimentm and desmin, for a-smooth muscle-actin and rough endoplasmic reticulum (rER).In the pectinate ligament and in the region adjacent to the aqueous plexus, the cells were found to have especially abundant rER and glycogen in their cytoplasm. Vimentin was abundant in the reticular meshwork as positive staining was seen both in frozen and partin sections. Alpha-smooth muscle-a&in could be found in the region connecting ciliary muscle and reticular meshwork as well as in a small area adjacent to the posterior capillary loops of the aqueous plexus. Ultrastructurally, these cells resembled myofibroblasts. The ciliary muscle cells stained both for vimentin and for a-smooth muscle actin.

No abstract

The scieral spur in 37 human (age 17-87 years) and six cynomolgus monkey eyes (2-4 years) was investigated. Serial meridional and tangential sections were studied with ultrastructural and immunocytochemical methods. The bundles of the ciliary muscle do not enter the scleral spur, but their tendons, which consist of elastic fibres join the elastic fibres in the scleral spur. Within the scleral spur a population of circularly oriented and spindle-shaped cells is found. In contrast to the ciliary muscle cells, the scleral spur cells form no bundles, but are loosely aggregated. They have long cytoplasmic processes and are connected to each other by adherens-type and gap junctions. They stain intensely for a-smooth muscle actin. myosin and vimentin. In contrast to the ciliary muscle cells, they do not stain for desmin. Ultrastructurally, the scleral spur cells contain abundant thin (actin) filaments, but do not otherwise show the typical ultrastructural features of ciliary muscle cells. The scleral spur cells do not express a complete basal lamina. They form individual tendinous connections with the elastic fibres in the scleral spur, which are continuous with the elastic fibres of the trabecular meshwork. The scleral spur cells are in close contact with nerve terminals containing small agranular (30-60 nm) and large granular (65-l 10 nm) vesicles but also with terminals containing small granular (30-60 nm) vesicles which are regarded as typical for adrenergic terminals. We conclude that the scleral spur cells are contractile myofibroblasts. Their contraction might influence the rate of the aqueous outflow.

No abstract

In primates, ciliary muscle contraction causes accommodation and facilitates aqueous outflow. In living rhesus monkeys, accommodative, outflow facility, and ciliary muscle movement responses to cholinergic agonists all decline with age. We developed an apparatus to determine in vitro whether the latter is related to intra- or extra-ciliary muscle factors, and whether ciliary muscle contraction in the coronal (putatively more accommodation-relevant) and longitudinal (putatively more facility-relevant) vectors can be dissociated pharmacologically. In fresh ciliary muscle strips, carbachol and aceclidine each induced dose-dependent contraction in the longitudinal and coronal vectors. With neither drug was there any apparent dissociation of the responses in the two vectors. Atropine pretreatment completely prevented a supramaximal dose of carbachol from inducing ciliary muscle contraction in either vector. Ciliary muscle strips responded to several cholinergic agonists as well on day 2 (24-32 hours post-enucleation) as on day 1 (1-9 hours post-enucleation) when kept in a cell culture medium at 4 degrees C. By light microscopy, the general architecture of the ciliary muscle, the muscle bundles, and the single muscle cells appeared normal; however, cellular and nuclear swelling were apparent following the 32-hour culturing period. Contractile responses to near-maximal doses of carbachol and aceclidine did not vary markedly with age in either vector, suggesting that the age-related decrease in ciliary muscle mobility in vivo is due to extra-muscular restrictive factors rather than diminished muscular contractility.