Ultrasonic Vocalizations in Rats Compared to Physiological Means (Heart Rate and Blood Pressure)

Abstract

In the field of laboratory research, animals are often used for testing drugs before they become available to the human market. With the well being of these animals in mind many processes are done to insure the animal has maximized care. Accordingly, the field of Ultrasonic Vocalization (USV) monitoring has grown in an effort to measure stress in a rat model without having to use an intrusive method of measuring stress. 24 kHz frequency USVs have been long accepted as a measure of stress in rats; due to their association with negative drugs or environments. However, no data exists that correlates these vocalizations with a coincident physiological indication of stress, such as a sympathetic change. In an effort to increase care standards, this project attempted to correlate two measures of stress to 24 kHz vocalizations in a rat model, increased heart rat and blood pressure. Vocalizations were observed using a bat-ultrasonic detector; blood pressure and heart rate were monitored with use of an implanted telemetry system. A positive correlation could lead to increased animal care, but we observed no significant correlation relating the stress models to 24 kHz USV production.