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Alcohol‐Preferring P Rats Emit Spontaneous 22‐28 kHz Ultrasonic Vocalizations that are Altered by Acute and Chronic Alcohol Experience
Author(s) -
Reno James M.,
Thakore Neha,
Gonzales Rueben,
Schallert Timothy,
Bell Richard L.,
Maddox W. Todd,
Duvauchelle Christine L.
Publication year - 2015
Publication title -
alcoholism: clinical and experimental research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.267
H-Index - 153
eISSN - 1530-0277
pISSN - 0145-6008
DOI - 10.1111/acer.12706
Subject(s) - alcohol , ethanol , alcohol intake , medicine , endocrinology , chemistry , psychology , biochemistry
Background Emotional states are often thought to drive excessive alcohol intake and influence the development of alcohol use disorders. To gain insight into affective properties associated with excessive alcohol intake, we utilized ultrasonic vocalization ( USV ) detection and analyses to characterize the emotional phenotype of selectively bred alcohol‐preferring (P) rats; an established animal model of excessive alcohol intake. USV s emitted by rodents have been convincingly associated with positive (50‐55 kHz frequency‐modulated [FM]) and negative (22‐28 kHz) affective states. Therefore, we hypothesized that 50‐55 and 22‐28 kHz USV emission patterns in P rats would reveal a unique emotional phenotype sensitive to alcohol experience. Methods 50‐55 kHz FM and 22‐28 kHz USV s elicited from male P rats were assessed during access to water, 15 and 30% Et OH (v/v). Ethanol (EtOH; n = 12) or water only (Control; n = 4) across 8 weeks of daily drinking‐in‐the‐dark ( DID ) sessions. Results Spontaneous 22‐28 kHz USV s are emitted by alcohol‐naïve P rats and are enhanced by alcohol experience. During DID sessions when alcohol was not available (e.g., “Et OH OFF ” intervals), significantly more 22‐28 kHz than 50‐55 kHz USV s were elicited, while significantly more 50‐55 kHz FM than 22‐28 kHz USV s were emitted when alcohol was available (e.g., “Et OH ON ” intervals). In addition, USV acoustic property analyses revealed chronic effects of alcohol experience on 22‐28 kHz USV mean frequency, indicative of lasting alcohol‐mediated alterations to neural substrates underlying emotional response. Conclusions Our findings demonstrate that acute and chronic effects of alcohol exposure are reflected in changes in 22‐28 and 50‐55 kHz FM USV counts and acoustic patterns. These data support the notion that initiation and maintenance of alcohol intake in P rats may be due to a unique, alcohol‐responsive emotional phenotype and further suggest that spontaneous 22‐28 kHz USV s serve as behavioral markers for excessive drinking vulnerability.