Beta-adrenoreceptor blockade abolishes atomoxetine-induced risk taking

Area of Science:

• Neuroscience
• Behavioral Pharmacology

Background:

• Clinical studies link high norepinephrine levels to exaggerated risk-taking tendencies.
• Norepinephrine plays a crucial role in modulating behavioral responses to risk and reward.

Purpose of the Study:

• To investigate the impact of manipulating norepinephrine levels on risk-taking behavior in a rat model.
• To explore the specific roles of beta- and alpha-adrenergic receptors in mediating these effects.

Main Methods:

• Rats were trained on a probabilistic discounting task involving a choice between a small, certain reward and a larger, uncertain reward.
• Systemic administration of atomoxetine (a norepinephrine reuptake inhibitor) and adrenergic antagonists (propranolol, prazosin) to assess their effects on lever choices.

Main Results:

• Atomoxetine administration dose-dependently increased the selection of the risky option, indicating enhanced risk-taking.
• Atomoxetine reduced the lose-shift effect, suggesting decreased aversion to losses, without altering the win-stay effect.
• Co-administration of propranolol (a beta-adrenoreceptor antagonist) blocked atomoxetine's effects on risk-taking and lose-shift behavior, while prazosin (an alpha1-adrenoreceptor antagonist) did not.

Conclusions:

• Increased norepinephrine levels, induced by atomoxetine, enhance risk-taking behavior in rats.
• This enhancement of risk-taking is associated with a reduced sensitivity to losses.
• The observed effects are primarily mediated through beta-adrenoreceptor pathways.