[Advances in the research of opioid receptor and ion channels of dorsal root ganglion neurons].

With the development of cDNA cloning technique in molecular biology, the research of opioids and opioid receptor as well as the mechanism of peripheral analgesia have made a great progress in the fields of receptor researches including molecular structure, morphology, molecular pharmacology, ion channel and intercellular signal transduction systems. The functional properties of mu, delta and kappa opioid receptor were determined by their structures. Depending on different proportional distribution in the primary sensory neurons, opioid receptor activation increases or decreases the potassium current and inhibits the calcium channel. There are different second message systems which are involved in the signal transduction between opioid receptors and ion channels. In addition, pharmacological evidence has also proved the existence of sub-types of opioid receptor, and the activation of these receptors can inhibit transmitters release from primary sensory neuron directly, which may be an important mechanism that opioid receptor has an analgesic effect in the peripheral nervous system.