CRF-induced seizures and behavior: interaction with amygdala kindling

Area of Science:

• Neuroscience
• Endocrinology

Background:

• Corticotropin-releasing factor (CRF) is implicated in stress and seizure disorders.
• Previous studies suggest CRF can induce seizures, but its long-term effects on seizure development are unclear.

Purpose of the Study:

• To investigate the impact of repeated intracerebroventricular (i.c.v.) CRF administration on seizure development and subsequent amygdala kindling.
• To assess tolerance to CRF-induced seizures and aggressive behavior.
• To determine if prior CRF exposure influences the progression of electrical kindling.

Main Methods:

• Rats received daily i.c.v. injections of CRF (100 micrograms) or vehicle for 5 days, monitoring for seizures and behavior.
• Electrical kindling of the amygdala was performed after the CRF regimen.
• A separate experiment involved administering CRF to already kindled or sham-kindled rats.

Main Results:

• Initial CRF administration induced late-onset seizures and aggressive behavior, but tolerance developed by day 5.
• Rats previously treated with CRF showed accelerated development of amygdala-kindled seizures compared to controls.
• Kindled rats exhibited reduced sensitivity to CRF-induced seizures but increased aggression.

Conclusions:

• Repeated CRF administration leads to tolerance for its acute proconvulsant and behavioral effects.
• Prior exposure to CRF primes the brain, enhancing susceptibility to amygdala kindling.
• CRF's role in seizure susceptibility and aggression is complex, influenced by prior kindling experience.