[Arousal and the psychopharmacology of anxiety in experimental models].

Locomotion is a behavioural marker of arousal in animals whereas exploration serves as a reliable criterion for anxiety level. Traditional views of central excitatory mechanisms consider them as pro-arousal and anxiogenic. Central inhibitory mechanisms are thought to be sedative and anxiolytic. However, data exist on paradoxical anti-anxiety effects of low doses of certain anxiolytics in a number of experimental models. Likewise, anxiolytics might exert paradoxical pro-arousal/anxiogenic profiles in animals. Both such data are difficult to interpret within traditional framework of arousal/anxiety concepts. The paper reviews data on complex non-linear interrelationships between anxiety and arousal and supports a theory of putative "anxiolytic" (comfort or pleasurable) emotions evoked by mild, but not high, arousal.