CRF and restraint-stress decrease exploratory behavior in hypophysectomized mice

Area of Science:

• Neuroscience
• Behavioral Endocrinology
• Stress Research

Background:

• Corticotropin-releasing factor (CRF) and acute stress are known to suppress exploratory behaviors in rodents.
• The role of the pituitary-adrenal axis in mediating these behavioral effects has been investigated.

Purpose of the Study:

• To determine if pituitary-adrenal hormones are essential for the reduction of exploratory behavior induced by restraint stress and CRF.
• To investigate the central mechanisms underlying stress-induced behavioral suppression.

Main Methods:

• Utilized hypophysectomized mice to eliminate pituitary-adrenal hormone influence.
• Administered restraint stress and intracerebroventricular injections of CRF.
• Assessed changes in exploratory behavior.
• Tested the effect of a CRF antagonist on restraint-induced behavioral changes.

Main Results:

• Restraint stress significantly decreased exploratory behavior in hypophysectomized mice, similar to intact animals.
• CRF administration into the lateral ventricles also reduced exploratory behavior in hypophysectomized mice.
• A CRF antagonist successfully reversed the effects of restraint stress on exploratory behavior.

Conclusions:

• The suppressive effects of restraint stress and CRF on exploratory behavior are independent of ACTH secretion from the pituitary.
• CRF appears to act within the brain (intracerebrally) to mediate the behavioral effects of restraint stress.