Continous, simultaneous, and instant display of aqueous humor dynamics with a micro-spectrophotometer and a sensitive drop counter

Dopaminergic Involvement in Intraocular Pressure in the Rabbit Eye

“…in the eyes [1], Its mechanism to lower IOP is not related to (3-adrenergic blockade [10], prostaglandin inhibition [1,11], ATPase inhibition [1], or carbonic anhydrase reduction [12]. Timolol's abilities to eliminate dopaminer gic function and reduce blood flow to ciliary body are logical alternative hypotheses to be offered for its mode of action [1] and are supported in this study.…”

Dopaminergic Involvement in Intraocular Pressure in the Rabbit Eye

“…in the eyes [1], Its mechanism to lower IOP is not related to (3-adrenergic blockade [10], prostaglandin inhibition [1,11], ATPase inhibition [1], or carbonic anhydrase reduction [12]. Timolol's abilities to eliminate dopaminer gic function and reduce blood flow to ciliary body are logical alternative hypotheses to be offered for its mode of action [1] and are supported in this study.…”

A major pathway for the regulation of intraocular pressure

“…Second, timolol acts like a beta adrenergic blocker in vivo at a concentration lower than that required for its pressure reducing effect in the eye and yet at a concentration consistent with its Kd for binding to beta adrenergic receptors in ciliary processes (15). Third, d-timolol lowers IOP (24). This finding indicates a lack of stereospecificity for the beta receptor.…”

Effect of Silibinin in Lowering the Intraocular Pressure in Normotensive Rabbits: Interaction with Betaxolol

“…Since agonists to all βadrenergic receptors (β 1 , β 2 , and β 3 ) stimulate adenylcyclase via interaction with Gs-protein to increase cAMP production, betaxolol was thought to lower IOP by reducing the intracellular concentrations of cAMP (16) . However, it has long been unclear whether the putative reduction in cAMP itself causes the reduction in IOP, an observation reported by Liu et al (1981) who demonstrated that Dtimolol, another β-blocker might be as effective as L-timolol in decreasing aqueous flow (17) , despite stereospecificity of the βadrenergic receptors for the L-isomers (18) . Meanwhile, if betaxolol reduces aqueous humor formation by blocking β-adrenergicmediated increase of cAMP production, one would expect cAMP itself to increase inflow.…”

Dopaminergic Involvement in Intraocular Pressure in the Rabbit Eye

“…in the eyes [1], Its mechanism to lower IOP is not related to (3-adrenergic blockade [10], prostaglandin inhibition [1,11], ATPase inhibition [1], or carbonic anhydrase reduction [12]. Timolol's abilities to eliminate dopaminer gic function and reduce blood flow to ciliary body are logical alternative hypotheses to be offered for its mode of action [1] and are supported in this study.…”

A major pathway for the regulation of intraocular pressure

“…Second, timolol acts like a beta adrenergic blocker in vivo at a concentration lower than that required for its pressure reducing effect in the eye and yet at a concentration consistent with its Kd for binding to beta adrenergic receptors in ciliary processes (15). Third, d-timolol lowers IOP (24). This finding indicates a lack of stereospecificity for the beta receptor.…”

Effect of Silibinin in Lowering the Intraocular Pressure in Normotensive Rabbits: Interaction with Betaxolol

“…Since agonists to all βadrenergic receptors (β 1 , β 2 , and β 3 ) stimulate adenylcyclase via interaction with Gs-protein to increase cAMP production, betaxolol was thought to lower IOP by reducing the intracellular concentrations of cAMP (16) . However, it has long been unclear whether the putative reduction in cAMP itself causes the reduction in IOP, an observation reported by Liu et al (1981) who demonstrated that Dtimolol, another β-blocker might be as effective as L-timolol in decreasing aqueous flow (17) , despite stereospecificity of the βadrenergic receptors for the L-isomers (18) . Meanwhile, if betaxolol reduces aqueous humor formation by blocking β-adrenergicmediated increase of cAMP production, one would expect cAMP itself to increase inflow.…”

Dopaminergic Involvement in Intraocular Pressure in the Rabbit Eye

“…in the eyes [1], Its mechanism to lower IOP is not related to (3-adrenergic blockade [10], prostaglandin inhibition [1,11], ATPase inhibition [1], or carbonic anhydrase reduction [12]. Timolol's abilities to eliminate dopaminer gic function and reduce blood flow to ciliary body are logical alternative hypotheses to be offered for its mode of action [1] and are supported in this study.…”

A major pathway for the regulation of intraocular pressure

“…Second, timolol acts like a beta adrenergic blocker in vivo at a concentration lower than that required for its pressure reducing effect in the eye and yet at a concentration consistent with its Kd for binding to beta adrenergic receptors in ciliary processes (15). Third, d-timolol lowers IOP (24). This finding indicates a lack of stereospecificity for the beta receptor.…”

Effect of Silibinin in Lowering the Intraocular Pressure in Normotensive Rabbits: Interaction with Betaxolol

“…Since agonists to all βadrenergic receptors (β 1 , β 2 , and β 3 ) stimulate adenylcyclase via interaction with Gs-protein to increase cAMP production, betaxolol was thought to lower IOP by reducing the intracellular concentrations of cAMP (16) . However, it has long been unclear whether the putative reduction in cAMP itself causes the reduction in IOP, an observation reported by Liu et al (1981) who demonstrated that Dtimolol, another β-blocker might be as effective as L-timolol in decreasing aqueous flow (17) , despite stereospecificity of the βadrenergic receptors for the L-isomers (18) . Meanwhile, if betaxolol reduces aqueous humor formation by blocking β-adrenergicmediated increase of cAMP production, one would expect cAMP itself to increase inflow.…”