Prolonged rewarding stimulation of the rat medial forebrain bundle: neurochemical and behavioral consequences.
Extracellular dopamine levels were measured in the rat nucleus accumbens by means of in vivo microdialysis. Delivery of rewarding medial forebrain bundle stimulation at a low rate (5 trains/min) produced a sustained elevation of dopamine levels, regardless of whether train onset was predictable. When the rate of train delivery was increased to 40 trains/min, dopamine levels rose rapidly during the first 40 min but then declined toward the baseline range. The rewarding impact of the stimulation was reduced following prior delivery of stimulation at the high, but not the low, rate. These results support the idea that dopamine tone plays an enabling role in brain stimulation reward and is elevated similarly by predictable and unpredictable stimulation.
Hernandez
Giovanni
G
Center for Studies in Behavioural Neurobiology, Concordia University, Montreal, PQ, Canada.
Hamdani
Selma
S
Rajabi
Heshmat
H
Conover
Kent
K
Stewart
Jane
J
Arvanitogiannis
Andreas
A
Shizgal
Peter
P
D000818:Animals; D001522:Behavior, Animal / Q000502:physiology* / Q000528:radiation effects; D001923:Brain Chemistry / Q000528:radiation effects; D004298:Dopamine / Q000378:metabolism; D004558:Electric Stimulation / Q000379:methods; D008297:Male; D008474:Medial Forebrain Bundle / Q000502:physiology* / Q000528:radiation effects; D017551:Microdialysis / Q000379:methods; D008954:Models, Biological; D009714:Nucleus Accumbens / Q000378:metabolism; D051381:Rats; D020318:Rats, Long-Evans; D012055:Reinforcement Schedule; D012201:Reward; D012646:Self Administration / Q000379:methods; D013997:Time Factors
D004298:Dopamine