Effect Of Ca～(2+)/calmodulin Dependent Protein Kinase Ⅱ Signal Pathway In Mechanisms On δ Opioid Receptor Dependence And Signal Transduction

Pharmacological studies have defined three major types of opioid receptors, delta, mu and kappa. Analgesia can be mediated through all these opioid receptor subtypes. A prominent characteristic of opiates is their ability to induce drug tolerance, dependence and addiction, the underlying cellular and molecular mechanisms remain elusive, although many studies have been carried out about them.The neuroblastma×glioma hybrid (NG108-15) cells, which display a variety of neuronal properties, have been shown to express CaMK â…¡ and the delta opioid receptor (DOR) as well as many other G protein-coupled receptors. Using this system, we undertook the present study to look into the potential role of CaMK II in opioid signal pathway. In this report, effect of Ca²⁺/calmodulin dependent protein kinase (CaMK â…¡) signal transduction in the opioid receptor and mechanism of opioid dependent signal pathway has been investigated using biochemical, molecular biological techniques and molecular pharmacological methods.At first, CaMK â…¡ from bovine cardiac muscle were extracted and purified, and CaMK â…¡ activity were measured. NG108-15 cells were treated with 5-opioid receptor specific agonist DPDPE for 48hr, activity of Ca²⁺/CaMK â…¡ signal pathway were measured. The relationships between Ca²⁺/CaMK â…¡ signal pathway and cAMP accumulation, and between Ca²⁺/CaMK â…¡ signal pathway and NOS activity were explored. Changes of 5-opioid receptor expression were studied using RT-PCR, when DPDPE were long-term administered to NG108-15 cells, and when naloxone was added to DPDPE long-term treatment NG108-15 cells.Our study not only have great theoretical values to elucidate changes of the Ca²⁺/ CaMK â…¡ signal pathway, but also provide strong experimental evidence for interactions between Ca²⁺/ CaMK â…¡ singal pathway and other signal transduction systems in development of opioids dependence and for mechanisms of opioids dependence in nucleus, offering novel...