Selective involvement of kappa opioid and phencyclidine receptors in the analgesic and motor effects of dynorphin-A-(1–13)-Tyr-Leu-Phe-Asn-Gly-Pro

Dynorphin A-(1–13)-Tyr-Leu-Phe-Asn-Gly-Pro (Dyn la; 1–8 nmol) injected intracerebroventricularly in the mouse produces two independent behavioraeffects: (1) a norbinaltorphimine (κ opioid antagonist)-reversible analgesia in the acetic acid-induced writhing test and (2) motor dysfunction characterized by wild running, pop-corn jumping, hindlimb jerking and barrel rolling and antagonized by the irreversible phencyclidine (PCP) and sigma (σ) receptor antagonist, metaphit and the non-competitive N- methyl- d-aspartate (NMDA) receptor antagonists, dextromethorphan and ketamine. The specific involvement of the PCP receptorin the motor effects of Dyn Ia is supported by the direct competitive interaction of the peptide with the binding of [ 3H]MK-801 ( K i: 0.63 μM) and [ 3H]TCP ( K i: 4.6 μM) to mouse brain membrane preparations.