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The Role of Corticotropin-Releasing Factor in the Behavior and Proinflammatory Activity of Separated Guinea Pig Pups

Year: 2012

Type: article

Abstract: The Role of Corticotropin-Releasing Factor in the Behavior and Proinflammatory Activity of Separated Guinea Pig Pups. _____________Isolation of guinea pig pups in a novel environment first produces active behaviors such as vocalizing and movement; over time, these behaviors wane and pups show characteristic passive responses similar to those produced by increased proinflammatory activity.Further, isolation of pups on two consecutive days has recently been shown to enhance those passive responses on the second day.Endogenous proinflammatory activity is thought to mediate the enhancement (sensitization).An injection of corticotropin-releasing factor (CRF) has been shown to increase passive behavior, possibly by increasing proinflammatory activity.The present study further investigated the role of CRF on proinflammatory activity and behavior during separation.In Experiment 1, pups were subcutaneously injected with 10µg of CRF or saline vehicle and then placed in a novel environment for 3 hr.CRF-injected pups exhibited more passive behavior and increased expression of the proinflammatory cytokine tumor necrosis factor alpha in the paraventricular nucleus of the hypothalamus when compared to saline injected pups.CRF increased plasma cortisol levels confirming that CRF activated the hypothalamic-pituitary-adrenal axis.In Experiment 2, pups were injected with either 75µg d-Phe 12-41 (CRF 12-41 ), a corticotropin releasing factor antagonist, or saline iv vehicle and separated for 3 hr on two consecutive days.CRF 12-41 increased active behaviors on Day 1. Passive behavior during separation was minimally affected by administration of the antagonist.In addition, passive responses increased from Day 1 to Day 2 in both the CRF 12-41 and saline groups.Together, these findings provide evidence that exogenous CRF increases passive behavior through a proinflammatory mechanism, but also raise questions about the role of endogenous CRF in the separation response.

Source: OhioLink ETD Center (Ohio Library and Information Network)

Author: Vincent Rasahd Alexander

Institution: Wright State University

Language: English

Topic: Stress Responses and Cortisol

Subfield: Behavioral Neuroscience

Field: Neuroscience

Domain: Life Sciences

SDG: Good health and well-being

Open Access status: green

Funder: National Institute of Mental Health

Award: Stress-Induced Sickness Behavior during Social Separation