  Decision under risk and uncertainty has been attracting attention in
neuroeconomics and neuroendocrinology of decision-making. This paper
demonstrated that the neurotransmitter receptor theory-based value (utility)
function can account for human and animal risk-taking behavior. The theory
predicts that (i) when dopaminergic neuronal response is efficiently coupled to
the formation of ligand-receptor complex, subjects are risk-aversive
(irrespective of their satisfaction level) and (ii) when the coupling is
inefficient, subjects are risk-seeking at low satisfaction levels, consistent
with risk-sensitive foraging theory in ecology. It is further suggested that
some anomalies in decision under risk are due to inefficiency of the coupling
between dopamine receptor activation and neuronal response. Future directions
in the application of the model to studies in neuroeconomics of addiction and
neuroendocrine modulation of risk-taking behavior are discussed.
