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GLUCOCORTICOID RECEPTOR INVOLVEMENT IN PAIR BONDING IN FEMALE PRAIRIE VOLES: THE EFFECTS OF ACUTE BLOCKADE AND INTERACTIONS WITH CENTRAL DOPAMINE REWARD SYSTEMS. Curtis, JT and Wang, Z. Neuroscience, 2005. Presented by: Yvonne Pao October 31, 2008. REWARD PROCESSING AND PAIR BOND FORMATION.
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GLUCOCORTICOID RECEPTOR INVOLVEMENT IN PAIR BONDING IN FEMALE PRAIRIE VOLES: THE EFFECTS OF ACUTE BLOCKADE AND INTERACTIONS WITH CENTRAL DOPAMINE REWARD SYSTEMS Curtis, JT and Wang, Z. Neuroscience, 2005. Presented by: Yvonne Pao October 31, 2008
REWARD PROCESSING AND PAIR BOND FORMATION Insel, TR 2003
NEUROCHEMICALS IN PAIR BONDING • Corticosterone: adrenal stress hormone; activates glucocorticoid receptors (GR) • Thought to enhance reward value • Opposing effects in males and females: • Adrenalectomy in females enhancement of pair bond formation • Adrenalectomy in males inhibition of pair bond formation Is decreased GR activation rewarding in females?
EXPERIMENT 1 • Reduce glucocorticoid receptor activation in female prairie voles via injection • Pair female with male for 6 hr non-sexual habitation • Test females for partner preference
EXPERIMENT 1 Aragona and Wang 2008
EXPERIMENT 2 • Pair bonds enhanced after GR blockade GR blockade is rewarding in females? • Hypothesis • GR blockade interacts with central dopamine systems (D1 and D2) of the “reward circuitry” • Approach • Pre-treat females with dopamine receptor antagonists before RU-486 treatment • Observe behavioral effects
CONCLUSIONS • Acute blockade of MRs and GRs facilitates pair bond formation in females • Acute reduction of GR activation increases reward value of male • Dopamine receptor antagonists can inhibit the effect of GR antagonists
DISCUSSION: GR BLOCKADE AND PAIR BONDING • Activation of GR and MRs produce opposing actions on different measures of other species • RU-486 and spironolactone have anti-gonadal effects • Enhanced pair bonding does not seem to result from these effects • Spironolactone treatment affects other behaviors • Suggests it acts centrally • Greatest concentration of MR found in hippocampus, which may alter activity of ventral tegmental area (VTA)
DISCUSSION: GR INTERACTION WITH DOPAMINE • D1 and D2 blockade antagonizes GR blockade by RU-486 • Effects of D1 receptor blockade were unexpected: • Previous studies indicate D1 blockade does not interfere with mating-induced partner preference • Mating and pair bonding involve different mechanisms? • Effects of D2 receptor were expected: • Has been found to play major role in pair bonds • Social stress alters dopamine release in NAcc (also implicated in prairie vole pair bonding) Corticosterone interact with dopamine in NAcc