ABSTRACT
Role of the 5-HT System in Modulating Anxiety States ..................................... 181 Mice with Targeted Genetic Inactivation in the Serotonergic System for the Study of Anxiety........................................................................................ 182 Behavioral Tests for Anxiety................................................................................. 183 Mice with Genetic Inactivation of 5-HT Receptors and the 5-HT Transporter...... 183
5-HT
Receptor Knockout Mice.............................................................. 184 5-HT
Receptor Knockout Mice.............................................................. 186 5-HT
Receptor Knockout Mice ............................................................... 186 5-HT
Receptor Knockout Mice ............................................................... 187 5-HT
Receptor Knockout Mice............................................................. 187 5-HT Transporter Knockout Mice............................................................. 188
Summary................................................................................................................ 189 References.............................................................................................................. 189
Anxiety is a normal reaction to threatening situations, and it represents a physiological protective function. Anxiety is often manifested as avoidance of threatening situations and is also characterized by overt sympathetic reactions. Pathological anxiety is a level of anxiety that is disproportionate to the threat and can be manifested even in the absence of threat. Individuals seem to have a consistent level of anxiety over their lifetime suggesting the importance of genetic factors. DSM-IV (American Psychiatric Association, 1994) and the International Classification of
Diseases [ICD-10] (World Health Organization, 1992), two categorical systems, set the boundary at which a particular level of anxiety becomes an anxiety disorder. These boundaries are often based on the number and the duration of symptoms. DSM-IV provides diagnostic criteria for anxiety disorders, including panic disorder (PD), specific and social phobias, obsessive compulsive disorder (OCD), posttraumatic stress disorder (PTSD), and generalized anxiety disorder (GAD) (American Psychiatric Association, 1994; Noyes, 2004).
