[The receptor organization of the reinforcing and analgetic opiate systems in the rat]

Comparative study of topographic and receptor selectivity of emotionally positive (place preference test) and analgetic (electrical and pressure nociceptive stimulation of the tail) effects of opioids was performed in rats. Morphine and selective agonists of mu-, kappa-, delta- and sigma-opiate receptors were administered through cannulae implanted into the periaqueductal grey and ventral tegmental area (VTA). Reinforcing effects of opioids in VTA was shown to be mediated mainly by mu-, delta- and sigma-receptors, while analgetic effect was realised with the aid of mu- and delta-opioid receptors.