Pharmacological studies in prairie voles have suggested that the neuropeptides oxytocin and vasopressin play important roles in behaviors associated with monogamy, including affiliation, paternal care, and pair bonding. Our laboratory has investigated the cellular and neuroendocrine mechanisms by which these peptides influence affiliative behavior and social attachment in prairie voles. Monogam...

The nucleus accumbens is a key mediator of cocaine reward, but the distinct roles of the two subpopulations of nucleus accumbens projection neurons, those expressing dopamine D1 versus D2 receptors, are poorly understood. We show that deletion of TrkB, the brain-derived neurotrophic factor (BDNF) receptor, selectively from D1+ or D2+ neurons oppositely affects cocaine reward. Because loss of Tr...

This study examined the effect on food intake of bilateral microinfusions of the benzodiazepine agents, diazepam and midazolam, the opioid agonist, morphine, and the GABA(A) agonist, muscimol into the shell of the nucleus accumbens in rats. Both muscimol (at 0.075 microg, combined bilateral dose) and morphine (1.0 microg) in the nucleus accumbens shell increased feeding as expected. However, it...

We investigated the involvement of the hippocampal formation and the amygdala in the acquisition and expression of the amphetamine-produced conditioned place preference (CPP). Animals were conditioned in four sessions that included two pairings of d-amphetamine (2.0 mg/kg, s.c.) with one of two distinct compartments and two pairings of vehicle with the other compartment in a counterbalanced man...

Selective blockers of the norepinephrine transporter (NET) inhibit dopamine uptake in the prefrontal cortex. This suggests that dopamine in this region is normally cleared by the somewhat promiscuous NET. We have tested this hypothesis by comparing the effects of inhibitors selective for the three monoamine transporters with those of a nonspecific inhibitor, cocaine, on uptake of 3H-dopamine in...

Modafinil may be useful for treating stimulant abuse, but the mechanisms by which it acts to do so are unknown. Indeed, a primary effect of modafinil is to inhibit dopamine transport, which typically promotes rather than inhibits motivated behavior. Therefore, we examined the role of nucleus accumbens extracellular glutamate and the group II metabotropic glutamate receptor (mGluR2/3) in modafin...

Classic drugs of abuse lead to specific increases in cerebral functional activity and dopamine release in the shell of the nucleus accumbens (the key neural structure for reward, motivation, and addiction). In contrast, caffeine at doses reflecting daily human consumption does not induce a release of dopamine in the shell of the nucleus accumbens but leads to a release of dopamine in the prefro...

Agonists and antagonists of dopamine, acetylcholine, and glutamate were injected bilaterally into the nucleus accumbens in 5 adult cats, and their effects on classically conditioned responses and locomotor activity were observed. Dopamine reduced conditioned consummatory responses (leg flexion and vocalization) and conditioned changes in respiration rate, but did not affect other conditioned pr...

Sensitization to drugs, such as amphetamine, is associated with alterations in the morphology of neurons in the nucleus accumbens, a brain region critical to motivation and reward. The studies reported here indicate that a strong natural motivator, sodium depletion and associated salt appetite, also leads to alterations in neurons in nucleus accumbens. Medium spiny neurons in the shell of the n...