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Opioid elevation of intracellular free calcium: possible mechanisms and physiological relevance

Damien S K Samways1, Graeme Henderson

  • 1Department of Pharmacological and Physiological Science, Health Science Center, School of Medicine, Saint Louis University, MO, USA. samwayds@slu.edu

Cellular Signalling
|October 4, 2005
PubMed

Insights

Opioid receptor activation can increase intracellular calcium levels ([Ca2+]i) through various mechanisms, sometimes requiring co-activation of other receptors. This calcium signaling has significant physiological implications.

Area of Science:

  • Cellular signaling pathways
  • Neuropharmacology
  • Molecular biology

Background:

  • Opioid receptors are Gi/G0 protein-coupled receptors involved in various intracellular signaling.
  • Opioid receptor activation typically inhibits adenylyl cyclase and modulates ion channels.
  • A growing body of evidence suggests opioid receptor activation can elevate intracellular calcium levels ([Ca2+]i).

Purpose of the Study:

  • To review the literature on opioid receptor-mediated elevations of intracellular calcium ([Ca2+]i).
  • To discuss the potential mechanisms underlying this calcium signaling phenomenon.
  • To explore the physiological relevance of opioid-induced calcium level changes.

Main Methods:

  • Literature review of studies investigating opioid receptor signaling.
  • Analysis of experimental data on intracellular calcium ([Ca2+]i) measurements.
  • Discussion of proposed molecular mechanisms.

Main Results:

  • Opioid receptor activation can elevate [Ca2+]i through direct or indirect pathways.
  • Indirect elevation often involves co-activation of Gq-coupled receptors and the inositol phosphate pathway.
  • The precise mechanisms for direct [Ca2+]i elevation remain under investigation.

Conclusions:

  • Opioid receptor-mediated increases in [Ca2+]i are a significant signaling event.
  • Understanding these mechanisms is crucial for comprehending opioid receptor function.
  • Further research is needed to fully elucidate the pathways and physiological roles of opioid-induced calcium signaling.

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