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Updated: Jul 1, 2026

Isolation of Retinal Arterioles for Ex Vivo Cell Physiology Studies
Published on: July 14, 2018
Ca2+-activated Cl- current in retinal arteriolar smooth muscle
Mary K McGahon1, Maurice A Needham, C Norman Scholfield
1Centre for Vision and Vascular Sciences, School of Medicine and Dentistry, The Queen's University of Belfast, Institute of Clinical Sciences, The Royal Victoria Hospital, United Kingdom.
This study characterizes the calcium-activated chloride current (I(Cl(Ca))) in retinal artery cells. This current, activated by calcium influx or release, contributes to vasoconstriction induced by certain agonists.
Area of Science:
- Cardiovascular Physiology
- Ocular Blood Flow Regulation
- Ion Channel Function
Background:
- Retinal arterioles are crucial for maintaining ocular blood flow.
- Understanding ion channel function in vascular myocytes is key to regulating blood flow.
- Calcium-activated chloride currents play a role in smooth muscle cell excitability.
Purpose of the Study:
- To investigate the biophysical and functional characteristics of the calcium-activated chloride current (I(Cl(Ca))) in retinal arteriolar myocytes.
- To determine the role of I(Cl(Ca)) in regulating retinal arteriolar tone.
- To elucidate the mechanisms of I(Cl(Ca)) activation in these cells.
Main Methods:
- Whole-cell perforated patch-clamp electrophysiology was employed on isolated retinal arteriolar myocytes.
- Pressure myography was used to assess changes in arteriolar tone.
- Pharmacological agents were used to block specific ion channels and currents.
Main Results:
- A calcium-activated chloride current (I(Cl(Ca))) was identified in retinal arteriolar myocytes.
- This current was activated by depolarization and sensitive to chloride channel blockers like DIDS.
- I(Cl(Ca)) magnitude was dependent on extracellular calcium and could be modulated by L-type calcium channel activity.
- Caffeine-induced currents, also sensitive to DIDS, suggest involvement of intracellular calcium stores.
- Disodium 4,4'-diisothiocyanatostilbene-2,2'-disulfonate (DIDS) inhibited endothelin-1-induced vasoconstriction.
Conclusions:
- Retinal arteriolar myocytes possess a calcium-activated chloride current (I(Cl(Ca))).
- I(Cl(Ca)) can be activated by calcium influx via L-type calcium channels or release from intracellular stores.
- This current contributes to agonist-induced vasoconstriction in the retinal vasculature.
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