Sustained morphine treatment augments prostaglandin E2-evoked calcitonin gene-related peptide release from primary sensory neurons in a PKA-dependent manner.

Abstract

Tissue damage leads to pain sensitization due to peripheral and central release of excitatory mediators such as prostaglandin E₂ (PGE₂). PGE₂ sensitizes spinal pain neurotransmitter such as calcitonin gene-related peptide (CGRP) release via activation of cyclic AMP (cAMP)/protein kinase A (PKA)-dependent signaling mechanisms. Our previous data demonstrate that sustained morphine pretreatment sensitizes adenylyl cyclase(s) (AC) toward the direct stimulator, forskolin, in cultured primary sensory neurons (AC superactivation). In the present work we investigated the hypothesis that morphine pretreatment also sensitizes ACs toward Gs-protein-coupled excitatory modulators (such as PGE₂), leading to augmented PKA-dependent CGRP release from PGE₂-stimulated primary sensory dorsal root ganglion (DRG) neurons. Our results show that sustained morphine treatment potentiated PGE₂-mediated cAMP formation and augmented PGE₂-evoked CGRP release from cultured primary sensory neurons in a PKA-dependent manner. Our data suggest that attenuation of AC superactivation in primary sensory neurons may prevent the development of opioid-induced hyperalgesia.

• Authors: Suneeta Tumati, William R Roeske, Todd W Vanderah, Eva V Varga
• Journal: European journal of pharmacology (Eur J Pharmacol) Vol. 648 Issue 1-3 Pg. 95-101 (Dec 01 2010) ISSN: 1879-0712 [Electronic] Netherlands
• PMID: 20826131 (Publication Type: Journal Article, Research Support, N.I.H., Extramural)
• Copyright: Published by Elsevier B.V.

Chemical References

• Neurotransmitter Agents
• Protein Kinase Inhibitors
• Receptors, Calcitonin Gene-Related Peptide
• Receptors, Prostaglandin E, EP2 Subtype
• Receptors, Prostaglandin E, EP4 Subtype
• Morphine
• Cyclic AMP
• Cyclic AMP-Dependent Protein Kinases
• Calcitonin Gene-Related Peptide
• Dinoprostone

Topics

• Animals
• Calcitonin Gene-Related Peptide (metabolism)
• Cell Differentiation (drug effects)
• Cyclic AMP (biosynthesis)
• Cyclic AMP-Dependent Protein Kinases (metabolism)
• Dinoprostone (metabolism, pharmacology)
• Dose-Response Relationship, Drug
• Drug Synergism
• Ganglia, Spinal (cytology, drug effects)
• Gene Expression Regulation (drug effects)
• Intracellular Space (drug effects, metabolism)
• Morphine (pharmacology)
• Neurotransmitter Agents (metabolism)
• Pain (metabolism)
• Protein Kinase Inhibitors (pharmacology)
• Rats
• Rats, Sprague-Dawley
• Receptors, Calcitonin Gene-Related Peptide (metabolism)
• Receptors, Prostaglandin E, EP2 Subtype (antagonists & inhibitors)
• Receptors, Prostaglandin E, EP4 Subtype (antagonists & inhibitors)
• Sensory Receptor Cells (cytology, drug effects, enzymology, metabolism)
• Time Factors