Cyelie-GMP-lndueed Depolarization and Increased Response Latency of Rods: Antagonism by Light

William H. Miller, Grant D. Nicol

Research output: Contribution to journalArticle

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Abstract

The results of the injection of excess cyclic guanosine 3´,5´-monophosphate (cGMP) suggest that the hydrolysis rates of cGMP in the rod outer segment (ROS) function in mediating transduction by regulating the Na+ permeability for some properties of both excitation and adaptation. This interpretation is supported by observations that excess intracellular cGMP in darkness depolarizes the ROS in a graded and transient manner, decreases membrane resistance, and uniquely regulates the latency, amplitude, and duration of the response to light. The effects of cGMP are antagonized by light in a dose-dependent manner. Physiological experiments suggest that (1) phosphodiesterase (PDE) activation is the rate-limiting step in excitation, (2) the latency and rising phase of the response may be triggered by cGMP hydrolysis, and (3) adaptation may reflect residual effects on either PDE activity or its balance with other regulatory components superimposed on inherent membrane time and voltage conductances.

Original languageEnglish (US)
Pages (from-to)417-437
Number of pages21
JournalCurrent Topics in Membranes and Transport
Volume15
Issue numberC
DOIs
StatePublished - Jan 1 1981

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ASJC Scopus subject areas

  • Molecular Biology
  • Cell Biology

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