title: Fear and anxiety: relationship to noradrenergic function.
abstract: The experiences of human fear and anxiety are discussed within the context of locus ceruleus function in animals. The rationale for studying correlates of noradrenergic function, such as 3-methoxy-4-hydroxyphenethylene glycol (MHPG), is reviewed, and data demonstrating a positive correlation between plasma free MHPG and state anxiety in normal volunteers is presented. The behavioral effects of oral caffeine (240-720 mg), intravenous clonidine (2 micrograms/kg), and oral yohimbine (20 mg) were studied in various psychiatric patients and normal volunteers. Caffeine and yohimbine had anxiogenic properties; conversely, clonidine reduced self-rated measures of anxiety across a wide spectrum of psychiatric conditions. These findings expand previous research indicating that noradrenergic hyperactivity may be associated with many types of human fear and anxiety.
mesh_terms: D000818:Animals; D001007:Anxiety / Q000139:chemically induced / Q000188:drug therapy / Q000503:physiopathology* / Q000517:prevention & control; D002110:Caffeine / Q000009:adverse effects; D003000:Clonidine / Q000627:therapeutic use; D004305:Dose-Response Relationship, Drug; D005239:Fear / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D008125:Locus Coeruleus / Q000502:physiology*; D013564:Sympathetic Nervous System / Q000502:physiology* / Q000503:physiopathology
chemical_list: D002110:Caffeine; D003000:Clonidine