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Purpose: To evaluate the influence of prostaglandin (PG) analogues on the ciliary zonular fibers of the crystalline lens using scanning electron microscopy (SEM) of rabbit eyes, and to measure the matrix metalloproteinase (MMP) and tissue inhibitor of metalloproteinase (TIMP) levels of the aqueous humor and crystalline lens treated with topical PG analogues Methods: Fifty eyes from 25 New Zealand white rabbits were divided into five groups of five rabbits each. In the control group, balanced salt solution was administered via the topical route once a day to the eyes. The benzalkonium chloride (BAC) group was treated with 0.02% BAC, the Latanoprost group with 0.005% latanoprost, the Travoprost group with 0.004% Travoprost, and the Bimatoprost group with 0.03% Bimatoprost for 10 months. We examined the ciliary zonular fibers using SEM. We also measured the MMP and TIMP levels of the aqueous humor and crystalline lens., Results: SEM revealed some splitting of zonular fibers in eyes treated with topical PG analogues when compared with the control and BAC groups. The MMP-1 and TIMP-1 levels after treatment with the PG analogues did not differ significantly from the control and BAC groups (P > 0.05). There was no significant difference in MMP-1, MMP-3, TIMP-1, and MMP-1/TIMP-1 levels in the lens among all five groups., Conclusions: PG analogues may induce zonular change in rabbits microscopically. There was no association between zonular changes and the levels of certain types of MMP or TIMP in the aqueous humor or crystalline lens after topical treatment with PG analogues.

Ciliary body is responsible for humour aqueous production in posterior chamber. Valproic acid (VPA) has been widely used for the treatment of epilepsy and other neuropsychiatric diseases such as bipolar disease and major depression. Oxcarbazepine (OXC) is a new anti-epileptic agent that has been used recently for childhood epilepsies such as VPA. In this study, we aimed to investigate the effects of VPA and OXC treatments used as antiepileptic in ciliary body by electron microscopy. In our study, 40 Wistar rats (21 days old) were divided equally into four groups which were applied saline (group 1), VPA (group 2), OXC (group 3) and VPA + OXC (group 4). The as-prepared ocular tissues were characterized by transmission electron microscopy (TEM) technique in scanning and transmission electron microscopy (SEM-TEM) (Carl Zeiss EVO LS10). The results confirmed that VPA caused dense ciliary body degeneration. Additionally, ciliary body degeneration in group 4 was supposed to be due to VPA treatment. Ciliary body damage and secondary outcomes should be considered in patients with long-term VPA therapy.

Purpose: To investigate the potential toxicity of the vehicle used for triamcinolone acetonide (TA) to the cornea, lens, ciliary body, and retina of pigmented rabbits., Methods: Forty chinchilla rabbits (40 eyes) were divided into four groups: group A (control group) eyes received an intravitreal injection of 0.1 ml sterile saline solution; group B eyes received 0.1 ml (1.3 mg) TA plus vehicle; group C eyes received 0.1 ml (1.3 mg) TA alone (vehicle eliminated); group D eyes received 0.1 ml vehicle only. Intraocular pressure (IOP) was measured pre-injection and at 1, 7, 14, 30, and 90 days post-injection. Scotopic and photopic electroretinograms (ERG) were examined pre-injection and 7, 30, and 90 days post-injection. Animals were sacrificed 7, 30, and 90 days post-injection. Eyes were enucleated and examined by light microscopy (LM) and electron microscopy (EM)., Results: The IOP of groups B and C was higher than that of other groups on days 1, 7, and 14 post-injection (p < 0.05). ERG amplitudes of groups B and D were lower than those of other groups on days 7 and 30 post-injection (p < 0.05). Histopathological sections indicated morphologic changes in the ciliary body, lens, and retina of eyes in groups B and D., Conclusions: Vehicle used for TA is toxic to the lens, ciliary body, and retina of pigmented rabbit eyes after injection of intravitreal TA.

Purpose: To evaluate the treatment parameters necessary for achieving ciliary body photodynamic damage, enough to significantly reduce IOP, using verteporfin and a diode laser., Design: Animal study., Methods: The right eye ciliary body of 30 pigmented rabbits was irradiated using verteporfin (Visudyne) and a diode laser. Photosensitizer dose ranged from 0.375 to 2 mg/kg. Three adjacent laser spots were applied 0.5 mm behind limbus at 12 o'clock position using a contact transscleral technique. The laser power was ranging from 10 to 70 mW and the duration of irradiation from 1 to 5 min per spot. The left eyes of the rabbits were used as controls. Animals were sacrificed 24 hours after the procedure and their eyes were evaluated by means of light and electron microscopy. A step-by-step approach was adopted with adjustment of experimental parameters according to histological findings. The end point was to identify the irradiation parameters necessary for induction of photodynamic damage while minimizing thermal damage. Subsequently, 10 more animals were used in order to verify the effectiveness of these irradiation parameters in reducing the intraocular pressure., Results: The therapy parameters that led to photodynamic effect avoiding thermal damage were laser power of 25 mW, irradiation time of 3 min per spot, and verteporfin dose of 1 mg/kg. Transscleral ciliary body irradiation using these parameters resulted in vascular thrombosis of ciliary vessels and in substantial edema, resulting in separation of the two ciliary epithelium layers. These parameters were applied to 4 rabbits, resulting in a mean IOP reduction of 1.8 mmHg +/- 1.2 that lasted for 4 days. An increase of the laser power to 35 mW tested in 6 additional animals, resulted in mean IOP reduction of 2.2 mmHg +/- 1.2, lasting 6 days; some minimal thermal damage was seen with the later settings., Conclusion: The combination of verteporfin and 690 nm diode laser is effective for the induction of ciliary body photodynamic damage, which results in significant but temporary IOP reduction, after transscleral PDT in pigmented rabbits. With appropriate parameter selection, intraocular pressure reduction can be achieved while thermal damage is kept to a minimum.

Purpose: Topical or intracameral administration of H-7 doubles outflow facility and reduces intraocular pressure in cynomolgus monkeys, by relaxing and expanding the trabecular meshwork (TM) and Schlemm's canal (SC). Since H-7 may have anti-glaucoma potential, we determined its effects on the corneal endothelium and ciliary epithelium for safety considerations., Methods: Following topical H-7, aqueous humor flow (AHF), corneal endothelial transfer coefficient (k(a)) and anterior chamber (AC) entry of i.v. fluorescein were measured by fluorophotometry; AC aqueous protein concentration ([Protein](AC)) was determined by Lowry assay; and corneal thickness and endothelial cell density and morphology were measured by ultrasonic pachymetry and specular microscopy respectively. Following intracameral H-7, specular and/or light and electron microscopy of the corneal endothelium or ciliary epithelium were performed., Results: Following unilateral topical H-7: (1) AHF and k(a) were essentially unchanged at 0.5--3.0, 3.5--6.0, and 0.5--6.0 hr, with an insignificant increase from 0.5--1.5 hr; (2) [Protein]( AC) was insignificantly increased at 1-1.5 hr but had returned to baseline by 2.5 hr; (3) entry of i.v. fluorescein into aqueous or cornea was modestly and transiently increased; (4) the central cornea thickened significantly at 1--2.5 hr, gradually returning to baseline 2.5 hr after H-7, while peripheral corneal thickness was less affected; (5) corneal endothelial cell borders became indistinct by 1 hr, but cell morphology was recovering by 3--5 hr and had completely returned to normal by 24 hr; (6) corneal endothelial cell density was unchanged at 5--24 hr. Following intracameral H-7, no significant changes were observed in corneal endothelial cell density or morphology by specular microscopy, nor in corneal endothelial or ciliary epithelial morphology by light and electron microscopy., Conclusions: A facility-effective intracameral dose of H-7 had no discernible structural effect on the corneal endothelium or ciliary epithelium. It is not yet clear whether carefully chosen topical doses of H-7 or analogues can enhance outflow facility without meaningfully affecting the cornea and ciliary processes.

Unlike smooth muscle elsewhere in the body, the smooth muscle of the iris and ciliary body is derived from neuroectoderm (mesectoderm). Leiomyomas that arise from the ciliary body, and therefore are of mesectodermal origin, may resemble spindle cell neurogenic tumors by light microscopy. They show positive immunostaining for smooth muscle actin but negative staining for neural markers. Ultrastructurally, the cells have the features of smooth muscle cells. The authors report a typical case of mesectodermal leiomyoma in a 47-year-old woman in which skeinoid fibers, considered to be an ultrastructural marker of neurogenic spindle cell tumors, were frequent together with other ultrastructural features often seen in neuroglial cell tumors. The findings indicate that mesectodermal leiomyoma is unique in its histogenesis as well as in its morphology.

Purpose: To study the presence of the cell-adhesion related HNK-1 carbohydrate epitope in the anterior segment of pseudoexfoliation and normal eyes by immunoelectron microscopy., Methods: Anterior segment tissue of 6 autopsy eyes with pseudoexfoliation (PEX) syndrome (5 eyes without glaucoma and 1 with glaucoma), and 6 normal autopsy eyes without PEX syndrome were studied by an electron microscopic immunogold technique using a monoclonal antibody to the HNK-1 epitope., Results: In both normal and PEX eyes, the HNK-1 epitope could be immunolocalized to the basement membranes of both ciliary epithelia and posterior iris pigmented epithelium, to the lens capsule and zonular lamella, and to the pigmented epithelial cells of iris and ciliary body. Within the inner connective tissue layer of the ciliary body, the gold label was mainly associated with the periphery of elastic fibers and microfibrillar bundles. PEX material on the surfaces of posterior iris, ciliary body, anterior lens capsule, zonular fibers, and uveal part of the trabecular meshwork reacted strongly with the HNK-1 antibody. In contrast, PEX material accumulations within the iris stroma or the juxtacanalicular tissue of the trabecular meshwork showed only weak immunoreactivity, while PEX material in the conjunctiva was totally negative., Conclusions: The wide distribution of the HNK-1 epitope in anterior segment tissues and its association with a variety of extracellular and cellular structures was ultrastructurally demonstrated. In PEX syndrome, the varying labelling density of PEX fibers indicates a deviating carbohydrate composition in different locations of the eye. The HNK-1 epitope might be involved in the adhesiveness of PEX deposits on intraocular surfaces.

Purpose: To examine the distribution of proteoglycans in the exfoliation materials in order to investigate the nature of the materials., Methods: The anterior parts of two eyes with exfoliation syndrome were examined by electron microscopy after staining with cupromeronic blue (cmb). Some specimens were treated with enzymes and/or nitrous acid prior to staining. The effects of the enzymes were evaluated statistically by counting the density of the cmb-positive filaments in the exfoliation materials, using a computer. One eye with exfoliation syndrome stained with alcian blue was observed with light microscopy., Results: Exfoliation materials were observed along the epithelial cells of the iris and ciliary body, and in the trabecular meshwork and zonules. In tissue specimens treated with cmb, electron-dense filaments were seen associated with the exfoliation materials. Microfibrils in the trabecular meshwork and iris, and zonular fibrils themselves were free of any filament staining, while the exfoliation materials located closely to the fibrils contained the electron-dense filaments. In the tissue specimens treated with chondroitinase AC, chondroitinase B, chondroitinase ABC or nitrous acid before cmb staining, the amount of the filament associated with exfoliation materials decreased in comparison to the controls. Digestion with keratinase did not demonstrate any significant changes in staining. A combination treatment with chondroitinase ABC and nitrous acid eliminated almost all filaments associated with the exfoliation materials. In the eye stained with alcian blue, the zonules that did not stain for the dye demonstrated an accumulation of exfoliation materials that stained strongly for alcian blue., Conclusions: Exfoliation materials contain chondroitin sulfate, dermatan sulfate, heparan sulfate proteoglycans. Depositions of proteoglycans on the microfibrils may be closely associated with the formation of exfoliation materials.

Prorenin (PR) was localized by electron microscopic (EM) immunostaining of cryo-ultramicrotomy sections of human ciliary body and correlated with light microscopic immunostaining. Both layers of the ciliary epithelium contained the prohormone. However, density was much higher in the adjacent extracellular spaces, particularly in the vitreous cortex. This observation adds further evidence to a role of the ciliary epithelium in the transfer, storage or synthesis of components of a putative ocular renin angiotensin system.

Although various growth factors have been identified in the human aqueous humor, their sources have not been fully established so far. To determine, whether the ciliary body epithelium is capable of producing growth factors in vivo, we studied the immunolocalization of EGF, bFGF, IGF-I, TGF-alpha, TGF-beta and PDGF-AB in human ciliary body tissue obtained from 20 autopsy eyes (12 to 88 years; fixed within 6 hours post mortem) and 1 surgically enucleated melanoma eye using light and electron microscopic immunohistochemistry. Antibody binding was visualized by indirect immunofluorescence and immunogold labeling on differently fixed frozen and resin-embedded sections. The immunohistochemical findings indicate the production of EGF, bFGF, IGF-I, and TGF-alpha, to a minor degree also TGF-beta, particularly TGF-beta 2, by the ciliary epithelial cells, predominantly the nonpigmented cells. Ultrastructural evidence for an endogenous production included the distinct and specific labeling of secretory organelles (rough endoplasmic reticulum, Golgi complex), cytoplasmic vesicles, and the basolateral membrane infoldings. The ciliary epithelium failed to stain significantly with antibodies to TGF-beta 1 and PDGF-AB. Labeling for bFGF was found to depend on the specific antibodies and fixation conditions employed. Sequestration of bFGF and PDGF-AB in the basement membranes of the ciliary epithelium could be demonstrated under certain conditions. Peaks of labeling intensity were consistently observed at the crests of the ciliary processes and in the pars plana, suggesting regional variations in activity and secretion of growth factors into the aqueous humor and vitreous. While only PDGF-AB may be derived from the serum, it appears likely that most growth factors demonstrated are not circulating hormones but rather act as autocrine and/or paracrine factors.

The production and spatial organization of connective tissue components in ciliary muscle cell cultures was studied with immunohistochemical and ultrastructural methods. Antibodies against collagen types IV and VI, fibronectin and laminin were used. Laminin stains as pericellular network surrounding individual muscle cells. Type IV collagen shows positive cytoplasmic staining and only small foci of extracellular immunofluorescence. Staining for type VI collagen and fibronectin is seen near the ends of the bipolar cells, while the lateral sides of the cells remain unstained. Electronmicroscopy shows that cultured ciliary muscle cells are surrounded by an incomplete basal lamina. In addition, bundles of 5-20 nm thick extracellular microfibrils are seen. The bundles are oriented parallel to the axis of the cells and are in close contact with the cell membrane in areas where membrane-bound dense bands are formed. Immunoelectronmicroscopy indicates that the bundles contain fibronectin and type VI collagen fibrils. While the fibronectin fibrils approach the cell membrane directly, type VI collagen fibrils are usually separated from the cell membrane by fine fibrillous material of different nature. Quality and spatial organization of the extracellular material in ciliary muscle cell cultures shows marked similarities with the extracellular matrix of ciliary muscle in situ.

We found in the previous study that the induction of 7-pentoxyresorufin O-dealkylase and 7-ethoxyresorufin O-dealkylase activities by phenobarbital and 3-methylcholanthrene, respectively, is more pronounced in porcine ciliary nonpigmented epithelial cells than in pigmented epithelial cells. In order to determine whether cytochrome P450 isozymes that mediate the O-dealkylase activities are also induced in nonpigmented cells under the conditions, primary cultures of porcine ciliary processes were treated with phenobarbital and 3-methylcholanthrene and the expression and localization of cytochrome P450 isozymes induced by these compounds were investigated by immunocytochemical methods using antibodies against the individual P450 isozymes. Intense labeling of nonpigmented epithelial cells was observed when ciliary processes treated with phenobarbital were reacted with anti-P450 (phenobarbital) antibody and when the processes treated with 3-methylcholanthrene were incubated with anti-P450 (methylcholanthrene) antibody. The labeling patterns supported the conclusion that the O-dealkylase activities and P450 isozymes specific for these activities are co-induced in and localized to the endoplasmic reticulum. This study is the first report presenting direct evidence of cytochrome P450 induction in primary cultures of ocular tissues and demonstrates the usefulness of porcine ciliary epithelial cells for studying the induction of ocular drug metabolizing enzymes.

Cynomolgus monkeys underwent unilateral panretinal scatter photocoagulation (PRP) and/or nasal and temporal horizontal retinal meridional photocoagulation (HRMP) with xenon arc or argon or krypton laser light. Shortly thereafter, in the PRP-treated eyes, accommodative responsiveness to topical eserine and electrical stimulation of the Edinger-Westphal nucleus (EWN) was diminished, accommodative responsiveness to intramuscular (i.m.) pilocarpine was enhanced, and the number of muscarinic receptors in the ciliary muscle was reduced compared to the contralateral controls. In most instances, these parameters returned to normal over 6-12 wks and the abnormalities could be induced again by another round of PRP. However, in some PRP-treated eyes, accommodative responsiveness to EWN stimulation and topical eserine remained subnormal permanently (greater than 1 yr). Shortly after HRMP alone, accommodative responses to i.m. pilocarpine, topical eserine, and central stimulation did not differ markedly in the treated and control eyes. Morphologic studies 1 to 78 wk following PRP revealed that myelinated and unmyelinated nerves within the entire circumference of the choroid and ciliary muscle were severely damaged early on. The number of unmyelinated nerves between the individual ciliary muscle fibers was drastically reduced, those which remained were swollen or deteriorated, and agranular synaptic vesicles were rarely seen. Thereafter, the nerves in the choroid and ciliary muscle gradually regenerated. Following HRMP, only the choroidal nerves which passed through the photocoagulated areas and the ciliary muscle nerves in the corresponding meridians showed signs of deterioration, and there was minimal effect on the physiologic responses examined. These findings collectively indicate that intraocular parasympathetic denervation of the ciliary muscle is produced by PRP, although all nerve types are likely damaged.

The morphologic changes in ciliary processes and the associated intraocular pressure (IOP) were observed in owl and squirrel monkeys after intravitreal (IVT) and intravenous (IV) injections of water soluble marijuana-derived material (MDM). The response in monkeys differed from that reported in rabbits wherein IV injection induced severe ciliary swelling and a significant decrease in IOP. Only moderate swelling occurs in monkey processes after IV injection of relatively high dose of MDM, and this change, which includes disruption of the basal lamina of the pigment epithelium, is not associated with a change in IOP. Severe swelling occurs in the crests of monkey ciliary processes after IVT injection, which is accompanied by a fall in IOP. The difference in the response in monkey versus rabbit ciliary processes after IV injection of MDM may be due to a more compact stroma in the monkey processes.

Ciliary body explants from 30 human eyes were maintained in organ culture up to 14 days. The age of the donors ranged from 45 to 85 years, the post mortem time from 4 to 22 hours. The ciliary epithelium as well as the underlying stroma were studied light- and electronmicroscopically before incubation and after 1, 3, 5, 7 and 14 days of culture. At the same time intervals, the localization of Na/K-ATPase and carbonic anhydrase (CA) were examined histochemically. If the cells were already damaged before incubation in medium (9 cases), they did not recover in culture. Best results were obtained after 3 to 5 days of culture with a survival rate of more than 90% after 3 days and more than 70% after 5 days, respectively. Both the nonpigmented (NPE) and the pigmented epithelium (PE) of the pars plicata in culture retained the morphological characteristics of epithelia involved in active secretion, namely elaborate infoldings of the cell membranes, numerous mitochondria in the cytoplasm and high activity of Na/K-ATPase and CA. In addition the adjacent capillaries were still fenestrated. After longer incubation times (7-14 days) the NPE and PE cells were filled with increasing amounts of lipid droplets and glycogen granules, indicating changes in metabolism.

Amyloid P protein was demonstrated by immunostaining in all 14 samples of ocular and conjunctival pseudoexfoliative (PSX) material studied, although amyloid was not found by Congo red staining or ultrastructurally. Immunostaining of PSX aggregates for other common amyloid proteins, including amyloid A, prealbumin, and immunoglobulin light chains, was negative in most cases. In three eyes with advanced neovascular glaucoma there was irregular immunostaining of the PSX aggregates for 2-4 of these other amyloid proteins, besides diffuse staining of the iris and vitreous. Control cases of neovascular glaucoma without PSX disease showed minimal amyloid P, but similar tissue staining for prealbumin and immunoglobulin light chains, consistent with an origin from vascular leakage. The presence of amyloid P protein, a minor serum component, in PSX aggregates in all cases with or without evidence of vascular leakage, indicated a more specific association. Ultrastructural localization of the protein on the periphery of PSX fibers suggest it is not an intrinsic fiber component. Since PSX material has an immunological relation to elastic tissue, we propose that PSX fibers have peripheral binding sites for amyloid P protein, similar to those present on normal elastic fibers.

To analyse the molecular mechanism of action of beta-adrenergic compounds in reducing the intraocular pressure, the binding of 125I-iodohydroxybenzylpindolol to bovine pigmented ciliary processes was studied. The binding was found to be highly specific, saturable, reversible and displayed stereospecificity. Only one class of binding sites was detected. Values for KD of 0.18 nM and 0.32 nM were derived from kinetic and equilibrium experiments, respectively. The total number of beta receptors was large : 1.28 pmoles/mg protein. Competitive inhibition of 125I-iodohydroxybenzylpindolol binding by agonists and antagonists revealed that the majority of beta receptors in bovine pigmented ciliary processes were of the beta 2 type. The pharmacological and biochemical characteristics of the binding of adrenergic drugs found in these membranes are consistent with a regulation of aqueous humor production by the beta adrenergic system.

The morphological changes in the inner surface of the human anterior chamber angle during pre and postnatal development were studied by light microscopy, scanning and transmission electron microscopy. Seventeen human foetal eyes (12-22 weeks) and ten infant and juvenile eyes (2.5 months--8 years) were investigated with the aim of establishing whether the trabecular meshwork is covered by an uninterrupted membrane at any stage in development. In 12-14 week old foetal eyes cuboidal corneal endothelial cells cover the inner surface of the anterior half to one third of the trabecular anlage. In this region there is a transition to more flattened uveal trabecular endothelial cells. Only rarely did corneal endothelial cells extend completely to the angle apex. The transition zone between corneal and uveal trabecular endothelial cells becomes located more anteriorly as development progresses. Intercellular gaps, which occur between uveal trabecular endothelial cells as early as 12-14 weeks in development, enlarge and become more frequent during development thus providing a route of communication between the anterior chamber and the developing intertrabecular spaces or channels. In the first months of life only a few cord-like uveal trabeculae orientated predominantly in a meridional direction overlie the more lamellate corneoscleral trabeculae. By the second year typical uveal trabeculae are more prominent and form a web-like arrangement. This is accompanied by a gradual decrease in the frequency of the cytoplasmic extensions of uveal trabecular endothelial cells which circumscribe the intratrabecular gaps. The timing of this remodelling and maturation appears to be remarkably variable between individuals. The implications of these findings on the theories of the pathogenesis of congenital glaucoma are discussed.

The tight junctions of the ciliary epithelium act as a barrier preventing the passage of blood borne macromolecules into the posterior chamber. The use of the freeze-fracture technique has led to a good knowledge of their morphological pattern in various species. However, in order to attempt a correlation of the morphology of the tight junctions with their physiological properties, their intimate substructure must be considered. As in other glutaraldehyde-fixed epithelia, the tight junctions appear as networks (variable in their apico-basal thickness) of more or less discontinuous P-face ridges and as complementary E-face furrows in which some particles or short bars are found. The significance of the discontinuities of ridges has been analysed. The continuity of the junctional fibrils was evident as assessed both by quantitative measurements as well as morphological examination of complementary fracture faces. In addition, the absence of loss of junctional material showed that the integrity of the junction was preserved during the freeze-fracture process, even in conditions where an increase in "transfer" of junctional elements was experimentally induced. Most of all, a "pore system" due to visualizable gaps in the fibrils is not tenable for the ciliary epithelium. Furthermore, the analysis of transition steps at the level of membrane "fusion" showed that the tight junctions of the ciliary epithelium must now be considered as formed by two slightly offset fibrils, one per adjacent plasma membrane.

By light and electron microscope radioautography in vivo, competitive binding sites for 125I-Arg 101-Tyr 126 atrial natriuretic factor were localized mostly on the "pigmented" epithelium of the rat ciliary process. Further investigation using isolated ciliary processes from rabbits demonstrated the presence of specific receptors for 125I-atrial natriuretic factor. In addition, synthetic atrial natriuretic factor inhibited basal and stimulated adenylate cyclase activity. These results demonstrate for the first time the presence of specific receptors for atrial natriuretic factor in the ciliary processes which are negatively coupled to adenylate cyclase. The possible role of this peptide in the control of intraocular pressure is suggested.

Anterior chamber paracentesis of the rabbit eye causes disruption of the blood-aqueous barrier, which is characterized by a rapid increase in the albumin and total protein content of the aqueous humor. Prostaglandins appear to be implicated as major mediators in this reaction, since a cyclooxygenase inhibitor, indomethacin, very efficiently prevents protein leakage. When paracentesis was performed in platelet-depleted rabbits (either by transfusion or by treatment with an antiplatelet plasma), the protein content in the aqueous humor did not rise to values observed in normal animals. These data suggest that platelets play some role in the response to paracentesis, a fact in accordance with histological results. In contrast to cyclooxygenase inhibitors, dexamethasone inhibits neither the blood-aqueous barrier breakdown nor prostanoid release from platelets. These data also indirectly indicate the possible role of platelets in triggering the paracentesis reaction in the rabbit.

The response of the ciliary processes of the rabbit eye to water-soluble marihuana-derived material (MDM) has been examined with light and electron microscopy. Following intravenous injection of MDM, the processes undergo considerable swelling within 1 hour followed by thrombus formation in the capillaries and extravasation of red cells. Later phases include the formation of cysts between the non-pigmented and pigmented cell layers of the ciliary epithelium. The ciliary process edema coincides with the initial hypertensive phase seen after intravenous MDM, while the hematogenous response coincides with the fall in intraocular pressure. Following intravitreal injection of MDM, a similar pattern of structural changes occurs that accompanies a fall in intraocular pressure that lasts for several days; because the physiological response occurs over a longer time course (14-20 hours) relative to intravenous administration where the intraocular pressure changes occur rapidly, the ciliary process swelling phase does not result in an increase in intraocular pressure. The physiologic changes in the eye caused by MDM appear to be related to the induction of a general inflammatory response in the ciliary processes, with a primary effect on the vascular system.

Methods were developed to isolate non-pigmented ciliary epithelium from bovine eyes (BCBE) free from other cell types in the ciliary process. Once background binding due to pigment was minimized, it was possible to assay specific beta adrenergic receptors in these preparations. The BCBE beta adrenergic receptors showed appropriate stereospecificity and an order of binding affinities compatible with a beta 2 adrenergic selectivity. Interestingly, specific high affinity muscarinic cholinergic receptors were detected in both BCBE and primate non-pigmented ciliary epithelium. These muscarinic receptors showed an appropriate affinity and selectivity for agonists and antagonists. Further evaluations of the receptors and responses of non-pigmented ciliary epithelial cells may prove useful in understanding the effects of adrenergic and cholinergic agents on aqueous humor inflow.

Using immunoelectron microscopy, the presence of elastin and tropoelastin was demonstrated in pseudoexfoliative (PSX) material in all its classical sites on the lens capsule, ciliary non-pigment epithelium, iris epithelium and stroma, and conjunctiva. Some variability in binding affinity was seen in different sites, and labelling was more often on the periphery than the center of the PSX fibers. The elastin epitope on PSX material was more sensitive to processing than the remarkably stable epitope on mature elastic fibers. Since neither elastin nor a related component of PSX fibers, elastic microfibrillar protein, is a circulating protein, both are likely to be secreted by local ocular cells. Most of these local cells are not involved in elastogenesis normally, suggesting that an abnormal stimulus or defective regulation of matrix synthesis exists in this disease.