Influence of Oxytocin on the Startle Reflex and on Its Modulation

Summary

Oxytocin (OXT) is currently regarded as a crucial neuropeptide in the mediation of various human social behaviors, e.g. social affiliation, social recognition, and the modulation of anxiety, mood, and aggression. An impairment of social behavior, emotional regulation as well as increased stress reactions are characteristic of several psychiatric conditions, including schizophrenia, social anxiety and PTSD, in which there is also some evidence for OXT dysfunction. The startle reflex is a basic defensive reaction that can be modulated by emotional stimuli. The investigation of the startle reflex and of its modulation is a well-validated method to test stress reactions and emotional regulation. These processes are impaired in the same psychiatric diseases, in which OXT dysfunction was evidenced. Although previous animal studies showed that the dysfunction of brain OXT systems might be implicated in startle reflex and in its modulation, no study has been performed yet in human that investigated the influence of OXT administration on the startle response and on its affective modulation. A first aim of this study is to investigate the influence of OXT on stress reactivity and emotional modulation in healthy humans. A second aim is to develop a method for the investigation of anxiety disorders. Fifty male healthy participants will be tested using a randomized double-blind placebo-controlled cross-over design in two occasions; once with administration of 24 IU OXT, and once with placebo using nasal sprays while performing a computer-based experiment, in which emotional pictures and auditory startle probes are presented. We will measure the subject's subjective ratings of the pictures as well as the facial EMG activation, heart rate and electrodermal activation throughout the study. This project offers a unique opportunity to study the relationship between the OXT system and basic motivational and emotional behaviors. The investigation of these mechanisms is in turn greatly worthwhile, not only for understanding of the neurochemical and physiological processes involved in emotional regulation, but also for the comprehension of the neuroendocrine and neurophysiological mechanismsunderlying anxiety disorders. In the long term, it could open the possibilities of OXT as a psychobiological therapeutics of psychiatric disorders.

Conditions

• Psychiatric Disorders

Interventions

DRUG

Syntocinon®

single dose of OXT (24 IU)

DRUG

inactive nasal spray

single dose (24 IU)

Sponsors & Collaborators

• University of Basel

  collaborator OTHER

• University of Freiburg

  collaborator OTHER

• University of Zurich

  lead OTHER

Principal Investigators

• Chantal Martin Soelch, PhD · University Hospital Zurich, Division of Psychiatry and Psychotherapy

Study Design

Allocation

RANDOMIZED

Purpose

BASIC_SCIENCE

Masking

DOUBLE

Model

CROSSOVER

Eligibility

Min Age

18 Years

Max Age

65 Years

Sex

MALE

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2010-05-31

Primary Completion

2012-09-30

Completion

2012-12-31

Countries

• Switzerland

Study Locations