Effects of adrenergic agents on transepithelial electrical measurements across the isolated iris-ciliary body

Theodore Krupin, Martin B. Wax, David A. Carré, Jay Moolchandani, Mortimer M. Civan

Research output: Contribution to journalArticlepeer-review

15 Scopus citations

Abstract

Transmembrane electrical measurements were performed on the isolated rabbit iris-ciliary body to study direct effects of adrenergic drugs on the ciliary epithelium. Alpha-adrenergic agonists (epinephrine, norepinephrine, or phenylephrine) lowered the short-circuit current (SCC) in a dose-dependent fashion relative to which chamber side the drug was added: simultaneous addition to both chambers > blood side only > aqueous side only. Pretreatment (5 × 10-5 m) with the non-selective β-adrenergic antagonist timolol had no effect while the non-selective α-adrenergic antagonist, phentolamine, completely prevented the α agonist-induced decrease in SCC. The α-adrenergic response was mediated by the α1 subtype since prazosin, but not yohimbine, blocked the induced reduction in SCC. The β-adrenergic agonist isoproterenol caused a dose-dependent decrease in the SCC. The decrease was similar when the drug was added to only the blood side or to both sides of the chamber. Addition to only the aqueous chamber had no effect. Pretreatment with β-adrenergic antagonists blocked the isoproterenol response: non-selective = selective β2 > selective β1. The isoproterenol-induced decrease in SCC was also blocked by non-selective α-adrenergic antagonists. The response was mediated by the α1 subtype since prazosin, but not yohimbine, blocked the isoproterenol response. This suggests that isoproterenol interacted with the α1-adrenergic sensitive pathway in the rabbit ciliary process.

Original languageEnglish (US)
Pages (from-to)709-716
Number of pages8
JournalExperimental Eye Research
Volume53
Issue number6
DOIs
StatePublished - Dec 1991

Keywords

  • iris-ciliary body
  • rabbit
  • short-circuit current
  • transepithelial measurements
  • α-adrenergic
  • β-adrenergic

ASJC Scopus subject areas

  • Ophthalmology
  • Sensory Systems
  • Cellular and Molecular Neuroscience

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