CB1-cannabinoid and mu-opioid receptor co-localization on postsynaptic target in the rat dorsal horn

Cannabinoids and opioids interact in the control of nociception at the spin al level. Likely, several mechanisms are involved, with one of them being c o-localization of cannabinoid and opioid receptors. In order to validate th is hypothesis, a double labeling study of CBI cannabinoid receptors and mu -opioid receptors in the dorsal horn of the rat spinal cord was performed. A strong co-localization of CBI I and L-opioid receptors was observed in la mina II interneurons at the ultrastructural level. The physiological conseq uences of the co-localization are discussed. NeuroReport 12:3689-3692 (C) 2 001 Lippincott Williams & Wilkins.