Flow of aqueous humor in the canal of Schlemm

Tandon, Pushkar; Autar, Ram

doi:10.1016/0025-5564(89)90013-8

Cited by 13 publications

(8 citation statements)

References 19 publications

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“…The delicate balance between the production and absorption of aqueous humor keeps the anterior chamber pressurized (~20 mm Hg) contributing to the maintenance of the curvature of the cornea. When this balance is disturbed glaucoma can occur (Tandon and Autar, 1989). Unlike most tissues in the body, the cornea is avascular; it contains no blood vessels to nourish it or to protect it against infection.…”

Section: Properties Of the Bovine Cornea With Focus On The Endotheliamentioning

confidence: 99%

Cx43-hemichannel function and regulation in physiology and pathophysiology: insights from the bovine corneal endothelial cell system and beyond

et al. 2014

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Intercellular communication in primary bovine corneal endothelial cells (BCECs) is mainly driven by the release of extracellular ATP through Cx43 hemichannels. Studying the characteristics of Ca2+-wave propagation in BCECs, an important form of intercellular communication, in response to physiological signaling events has led to the discovery of important insights in the functional properties and regulation of native Cx43 hemichannels. Together with ectopic expression models for Cx43 hemichannels and truncated/mutated Cx43 versions, it became very clear that loop/tail interactions play a key role in controlling the activity of Cx43 hemichannels. Interestingly, the negative regulation of Cx43 hemichannels by enhanced actin/myosin contractility seems to impinge upon loss of these loop/tail interactions essential for opening Cx43 hemichannels. Finally, these molecular insights have spurred the development of novel peptide tools that can selectively inhibit Cx43 hemichannels, but neither Cx43 gap junctions nor hemichannels formed by other Cx isoforms. These tools now set the stage to hunt for novel physiological functions for Cx43 hemichannels in primary cells and tissues and to tackle disease conditions associated with excessive, pathological Cx43-hemichannel openings.

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Section: Properties Of the Bovine Cornea With Focus On The Endotheliamentioning

confidence: 99%

Cx43-hemichannel function and regulation in physiology and pathophysiology: insights from the bovine corneal endothelial cell system and beyond

et al. 2014

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“…102,125,126 Results show that the region including the JCT-TM and the inner wall of Schlemm's canal is responsible for generating the major resistance to aqueous humor outflow, therefore having a great effect on IOP. 2,87,127,128 In Schlemm's canal, the net flow of aqueous humor moving across this endothelial monolayer is affected by both, IOP and episcleral venous pressure. These driving forces are similar in concept to lymph propulsion and lymph formation and in how they contribute to the regulation of lymph flow across the initial lymphatic endothelium.…”

Section: Lymphatic Endotheliamentioning

confidence: 99%

“…10 Thus, an increase in IOP progressively collapses the Schlemm's canal, affecting the canal dimensions and therefore the shear stress applied to the endothelia. 127 In vivo, physiologic factors affect the microenvironment of the inner wall ECs by altering the IOP. Diurnal oscillations in aqueous humor secretion can be observed with a sinusoidal behavior where the maximum rate is found at night (in the order of 3.4 mL/min) and the minimum is reported in the morning (approximately 1.5 mL/min).…”

Section: Inner Wall Of Schlemm's Canal Endotheliamentioning

confidence: 99%

Schlemm??s Canal Endothelia, Lymphatic, or Blood Vasculature?

Ramos

Hoying

Witte

et al. 2007

Journal of Glaucoma

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In the human eye, the final barrier for aqueous humor to cross before returning to systemic circulation is the inner wall of Schlemm's canal. Unfortunately, the specific contribution of the inner wall to total outflow resistance in the conventional pathway is unknown in both normal and glaucomatous eyes. To better understand inner wall physiology, we contrasted it with 2 specialized continuous endothelia, initial lymphatic, and blood capillary endothelia. Specifically, we compare their developmental origin, morphology, junctional complexes, microenvironment, and physiologic responses to different biomechanical factors. Our evaluation concludes that the inner wall of Schlemm's canal is unique, sharing extraordinary characteristics with both types of specialized endothelia in addition to having distinctive features of its own.

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“…The vacuum compressed the globe and reduced the volume of the anterior chamber, which immediately increased the pressure inside the eye and generated the sharp IOP peak. At that point, according to Poiseuille's law [13,14] [F = (P o -P v ) !C, where F is the rate of aqueous outflow, P o is the IOP, P v is episcleral venous pressure and C is the outflow facility], the rate of aqueous outflow increases drastically, since only P o , but not the other parameters, was increased in a short period of time. This sudden increase in outflow rate, coupled with the pressure-induced suppression of aqueous humor formation [15], caused the immediate decline of IOP.…”

Section: Discussionmentioning

confidence: 99%

Effect of Pneumatic Suction Ring Placement on Intraocular Pressure in Cats

Li¹

2001

Ophthalmic Res

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Purpose: To determine the effect of placing a pneumatic suction ring on intraocular pressure (IOP) in the cat and to design an improved method to generate a stable elevation of IOP. Methods: A pneumatic suction ring was applied to the eye in cats while the IOP was monitored. Three groups of animals (10 per group) were used. A vacuum pressure of 450 mbar was applied in one step to eyes of group 1 (anesthetized) and to group 2 (euthanized) cats. In group 3 (anesthetized) cats, an initial vacuum pressure of 250 mbar was applied, followed by a vacuum of slowly increasing pressure at a rate of 5 mbar/min for a total of 40 min to 450 mbar. Results: After the one-step application of a vacuum (450 mbar) to the eyes of anesthetized cats (group 1), IOP peaked within the first minute from a basal value of 25 ± 2 mm Hg (mean ± SD) to 90 ± 7 mm Hg. It then rapidly decreased to 69 ± 2 mm Hg 5 min later and continued to decrease to 39 ± 4 mm Hg 40 min later. This sharp peak and decline of IOP were also observed in eyes of euthanized cats (group 2). The basal IOP of these eyes was 8 ± 1 mm Hg. It rose to 18 ± 2 mm Hg immediately after the application of vacuum pressure (450 mbar) and returned to the basal level 5 min later. In contrast, the eyes of group 3 receiving an initial vacuum of 250 mbar followed by a 5 mbar/min vacuum increment exhibited a rapid increase in IOP and a very stable plateau (mean IOP = 62–68 mm Hg), lasting the whole study period (40 min). Conclusion: IOP after a one-step application of a vacuum via a pneumatic suction ring is self-adjusting and declines rapidly over time. This decline in IOP can be overcome by a supplementary increment in vacuum pressure.

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Flow of aqueous humor in the canal of Schlemm

Cited by 13 publications

References 19 publications

Cx43-hemichannel function and regulation in physiology and pathophysiology: insights from the bovine corneal endothelial cell system and beyond

Cx43-hemichannel function and regulation in physiology and pathophysiology: insights from the bovine corneal endothelial cell system and beyond

Schlemm??s Canal Endothelia, Lymphatic, or Blood Vasculature?

Effect of Pneumatic Suction Ring Placement on Intraocular Pressure in Cats

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