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Effect of potassium channel openers in acute and chronic models of glaucoma

Shital S Panchal1, Anita A Mehta2, Devdas D Santani3

  • 1Department of Pharmacology, Institute of Pharmacy, Nirma University, Ahmedabad 382481, Gujarat, India.

Taiwan Journal of Ophthalmology
|October 12, 2017
PubMed
Abstract

Insights

Nicorandil and pinacidil effectively lowered intraocular pressure (IOP) in glaucoma models. Their oculohypotensive effect, likely mediated by potassium channels, enhances aqueous humor outflow.

Area of Science:

  • Ophthalmology
  • Pharmacology

Background:

  • Glaucoma is a leading cause of irreversible blindness, characterized by elevated intraocular pressure (IOP).
  • Understanding the mechanisms and therapeutic agents for IOP reduction is crucial for glaucoma management.

Purpose of the Study:

  • To investigate the effects of nicorandil and pinacidil on intraocular pressure (IOP) in experimental acute and chronic glaucoma models.
  • To elucidate the mechanism of action underlying the IOP-modulating effects of these agents.

Main Methods:

  • Topical administration of nicorandil (1%), pinacidil (1%), and pilocarpine (1%) in New Zealand white rabbits.
  • Induction of acute glaucoma using dextrose (5%) and chronic glaucoma using α-chymotrypsin.
  • Measurement of IOP at regular intervals using a tonometer.
  • Investigating drug mechanisms using glibenclamide, pilocarpine, and indomethacin.

Main Results:

  • Nicorandil and pinacidil significantly reduced IOP in acute glaucoma models.
  • In chronic glaucoma, these drugs initially increased IOP (15-30 min) before causing a sustained reduction.
  • Glibenclamide pretreatment blocked the IOP-lowering effect, suggesting involvement of ATP-sensitive potassium channels.

Conclusions:

  • The oculohypotensive effect of nicorandil and pinacidil is likely mediated by enhancing aqueous humor outflow.
  • Potassium channels appear to play a significant role in the mechanism of action for these drugs in reducing IOP.
Keywords:
IOPcalcium channelsnicorandilpinacidilpotassium channels

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