Opposite effects of mesencephalic microinjections of cholecystokinin octapeptide and neurotensin-(1-13) on brain stimulation reward.
Changes in operant responding for brain stimulation reward were studied before and after a microinjection of 1 nmol of sulphated cholecystokinin octapeptide, neurotensin or saline into the ventral tegmental area. Neurotensin produced a significant and long lasting decrease in the stimulation frequency required to produce a half-maximal rate of responding; cholecystokinin had the opposite effect, attenuating the rewarding efficacy the stimulation during the first 30 min post-injection. It is suggested that the opposite effects of the peptides on reward are due to their differential modulatory effects on a subpopulation of mesencephalic dopamine neurones.
Rompré
P P
PP
Centre de Biomédecine de l'Hôpital du Sacré-Coeur, Département de Psychiatrie, Université de Montréal, Québec, Canada.
Boye
S M
SM
D000818:Animals; D003216:Conditioning, Operant / Q000187:drug effects; D004298:Dopamine / Q000502:physiology; D004558:Electric Stimulation; D008297:Male; D008636:Mesencephalon / Q000502:physiology*; D008845:Microinjections; D009496:Neurotensin / Q000008:administration & dosage / Q000494:pharmacology*; D051381:Rats; D012201:Reward; D012844:Sincalide / Q000008:administration & dosage / Q000494:pharmacology*
D009496:Neurotensin; D012844:Sincalide; D004298:Dopamine