Oxytocin-dopamine interactions mediate variations in maternal behavior in the rat.
Variations in maternal behavior among lactating rats associate with differences in estrogen-oxytocin interactions in the medial preoptic area (mPOA) and in dopamine levels in the nucleus accumbens (nAcc). Thus, stable, individual differences in pup licking/grooming (LG) are abolished by oxytocin receptor blockade or treatments that eliminate differences in the nAcc dopamine signal. We provide novel evidence for a direct effect of oxytocin at the level of the ventral tegmental area (VTA) in the regulation of nAcc dopamine levels. Mothers that exhibit consistently increased pup LG (i.e. high LG mothers) by comparison with low LG mothers show increased oxytocin expression in the mPOA and the paraventricular nucleus of the hypothalamus and increased projections of oxytocin-positive cells from both mPOA and paraventricular nucleus of the hypothalamus to the VTA. Direct infusion of oxytocin into the VTA increased the dopamine signal in the nAcc. Finally, high compared with low LG mothers show greater increases in dopamine signal in the nAcc during bouts of pup LG, and this difference is abolished with infusions of an oxytocin receptor antagonist directly into the VTA. These studies reveal a direct effect of oxytocin on dopamine release within the mesocorticolimbic dopamine system and are consistent with previous reports of oxytocin-dopamine interactions in the establishment and maintenance of social bonds.
Shahrokh
Dara K
DK
Sackler Program for Epigenetics and Psychobiology at McGill University, Douglas Mental Health University Institute, McGill University, Montréal, Canada.
Zhang
Tie-Yuan
TY
Diorio
Josie
J
Gratton
Alain
A
Meaney
Michael J
MJ
D000704:Analysis of Variance; D000818:Animals; D000831:Animals, Newborn; D004298:Dopamine / Q000378:metabolism*; D005260:Female; D006120:Grooming / Q000187:drug effects*; D008297:Male; D008425:Maternal Behavior / Q000187:drug effects*; D009714:Nucleus Accumbens / Q000187:drug effects / Q000378:metabolism; D010120:Oxytocics; D010121:Oxytocin / Q000378:metabolism / Q000494:pharmacology*; D010286:Paraventricular Hypothalamic Nucleus / Q000187:drug effects / Q000378:metabolism; D011301:Preoptic Area / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D020318:Rats, Long-Evans; D018045:Receptors, Oxytocin / Q000037:antagonists & inhibitors / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D017557:Ventral Tegmental Area / Q000187:drug effects / Q000378:metabolism
D010120:Oxytocics; D018045:Receptors, Oxytocin; D010121:Oxytocin; D004298:Dopamine