Opioid inhibition of Ih via adenylyl cyclase

Susan L. Ingram, John T. Williams

Research output: Contribution to journalArticlepeer-review

144 Scopus citations


Opioids are coupled through G proteins to both ion channels and adenylyl cyclase. This study describes opioid modulation of the voltage-dependent cation channel, Ih, in cultured guinea pig nodose ganglion neurons. Forskolin, PGE2, and cAMP analogs shifted the voltage dependence of activation of Ih to more depolarized potentials and increased the inward current at -60 mV. Opioids had no effect on In alone, but reversed the effect of forskolin on Ih. This action of opioids was blocked by naloxone. Opioids had no effect on In in the presence of CAMP analogs, suggesting that modulation occurs at the level of adenylyl cyclase. The shift in the voltage dependence of Ih by agents that induce inflammation (i.e., PGE2), is one potential mechanism to mediate an increased excitability. Opioid inhibition of adenylyl cyclase and subsequent inhibition of In may be a mechanism by which opioids inhibit primary afferent excitability and relieve pain.

Original languageEnglish (US)
Pages (from-to)179-186
Number of pages8
Issue number1
StatePublished - Jul 1994

ASJC Scopus subject areas

  • General Neuroscience


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