Pharmacologic evidence for nociception resulting from noncontingent "rewarding" brain stimulation.
Prolonged noncontingent electrical stimulation to rewarding brain sites will elicit escape behavior in rats. This study was designed to determine if this escape behavior is reinforced by the termination of a nociceptive stimulus or reinforced by the rewarding effects of the onset of the next stimulus. In the present experiment we determined the effects of the hyperalgesic naloxone (NX) and the analgesic ethylketocyclazocine (EKC) on the threshold for escape from electrical brain stimulation to the medial forebrain bundle-lateral hypothalamic area (MFB). Results indicate that EKC (0.5-1.0 mg/kg) raises the escape threshold, whereas NX (8.0-16.0 mg/kg) lowers the escape threshold, suggesting that escape from electrical brain stimulation to the MFB is the result of the nociceptive quality of stimulation and not the result of the rewarding effects of the onset of stimulation.
Pollock
J
J
Laboratory of Behavioral Pharmacology, Boston University School of Medicine, MA 02118.
Kornetsky
C
C
D000701:Analgesics, Opioid; D000818:Animals; D001143:Arousal / Q000187:drug effects*; D003496:Cyclazocine / Q000031:analogs & derivatives* / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004558:Electric Stimulation; D004924:Escape Reaction / Q000187:drug effects*; D016314:Ethylketocyclazocine; D007026:Hypothalamic Area, Lateral / Q000187:drug effects*; D008297:Male; D008474:Medial Forebrain Bundle / Q000187:drug effects*; D009042:Motivation; D009270:Naloxone / Q000494:pharmacology*; D009619:Nociceptors / Q000187:drug effects*; D051381:Rats; D011916:Rats, Inbred F344; D011957:Receptors, Opioid / Q000187:drug effects; D012684:Sensory Thresholds / Q000187:drug effects
D000701:Analgesics, Opioid; D011957:Receptors, Opioid; D009270:Naloxone; D016314:Ethylketocyclazocine; D003496:Cyclazocine