1. Selye H . The evolution of the stress concept Am Sci 1973; 61: 692–696
2. Akil HA, Morano IM . Stress. In: Kupfer D, Bloom F (eds) Psychopharmacology, the Fourth Generation of Progress Raven Press: New York 1995; pp773–785
3. Pani L, Gessa GL . Evolution of the dopaminergic system and its relationships with the psychopathology of pleasure Int J Clin Pharm Res 1997; 17: 55–58
4. Berridge KC, Robinson TE . What is the role of dopamine in reward: hedonic impact, reward learning, or incentive salience? Brain Res Rev 1998; 28: 309–369
5. Wise RA . The brain and reward. In: Liebman J, Cooper SJ (eds) The Neuropharmacological Basis of Reward Oxford University Press: Oxford 1989; pp377–424