Chronic treatment of rats with the specific sigma ligand D-pentazocine fails to modulate dopamine D2 and sigma binding in brain.
Drugs that bind at the sigma site have been proposed to have psychotomimetic and/or antipsychotic activity that is independent from that mediated by the phencyclidine (PCP) receptor. Some evidence suggests that sigma ligands may produce their effects by modulation of dopamine neurotransmission. The present study examined potential interactions between the sigma and dopamine system following chronic treatment with d-pentazocine, a specific sigma ligand that has negligible affinity for either PCP or dopamine receptors. Rats treated for one month with either saline or 10 mg/kg per day d-pentazocine revealed no significant differences in either the KD or Bmax of [3H]haloperidol-labeled sigma or [3H]YM-09151-2-labeled dopamine D2 receptors across multiple brain regions. These results are discussed in relation to the pharmacology of putative sigma-receptor subtypes.
Weissman
A D
AD
Addiction Research Center, National Institute on Drug Abuse, Baltimore, MD 21224.
De Souza
E B
EB
D000818:Animals; D001665:Binding Sites; D001921:Brain / Q000378:metabolism*; D004298:Dopamine / Q000378:metabolism* / Q000502:physiology; D008297:Male; D010423:Pentazocine / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D011954:Receptors, Dopamine / Q000378:metabolism*; D017448:Receptors, Dopamine D2; D011957:Receptors, Opioid / Q000378:metabolism*; D017465:Receptors, Opioid, delta; D009435:Synaptic Transmission / Q000187:drug effects*
D011954:Receptors, Dopamine; D017448:Receptors, Dopamine D2; D011957:Receptors, Opioid; D017465:Receptors, Opioid, delta; D010423:Pentazocine; D004298:Dopamine