The behavioural and electrophysiological effects of CRF in rat frontal cortex

• Published in: Neuropeptides (Edinburgh) Vol. 42; no. 5; pp. 513 - 523
• Main Authors: Zięba, Barbara, Grzegorzewska, Małgorzata, Brański, Piotr, Domin, Helena, Wierońska, Joanna M, Hess, Grzegorz, Śmiałowska, Maria
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.10.2008; Elsevier
• Subjects: Advanced Basic Science; Animals; Anti-Anxiety Agents - pharmacology; Anxiety; Behavior, Animal - drug effects; Biological and medical sciences; Corticotropin-Releasing Hormone - pharmacology; CRF; Electrophysiology; Endocrinology & Metabolism; Field potentials; Frontal cortex; Frontal Lobe - drug effects; Frontal Lobe - physiology; Fundamental and applied biological sciences. Psychology; Locomotor and exploratory activity; Male; Maze Learning - drug effects; Motor Activity - drug effects; NMDA receptors; Rats; Rats, Wistar; Receptors, Corticotropin-Releasing Hormone - agonists; Receptors, Corticotropin-Releasing Hormone - antagonists & inhibitors; Receptors, Corticotropin-Releasing Hormone - metabolism; Vertebrates: endocrinology; Locomotor and exploratory activity; Anxiety; Frontal cortex; Field potentials; NMDA receptors; CRF; Rat; Rodentia; Central nervous system; Corticotropin releasing factor; Electrophysiology; Glutamate receptor; Encephalon; Hypothalamic hormone; Locomotion; Vertebrata; Mammalia; Animal; Field potential; Behavior; Hormone releasing factor; NMDA receptor
• ISSN: 0143-4179; 1532-2785
• DOI: 10.1016/j.npep.2008.05.004

Abstract Corticotropin releasing factor (CRF) is a neuropeptide widely distributed in the brain. The role of CRF in the behavioural activity and modulation of anxiety states in several brain structures has been well documented, but its function in the cerebral cortex still remains unknown. The aim of our study was to investigate the effect of CRF injected bilaterally into rat frontal cortex on the locomotor and exploratory activity and anxiety of rats. We also examined the effect of CRF on extracellularly recorded field potentials in rat frontal cortical slices in vitro. Behavioural experiments showed that CRF in doses of 0.05, 0.1, 0.2 μg/1 μl/site decreased locomotor and exploratory activity during a 40-min session in the open field test. In the elevated plus-maze test, CRF in a dose of 0.2 μg/1 μl/site produced a significant anxiolytic-like effect, which was prevented by CRF receptor antagonists (α-helicalCRF(9-41) and NBI 27914). Electrophysiological experiments showed that CRF-induced a transient depression of field potentials in slices partly disinhibited by GABAA and GABAB receptors antagonists. The blockade of NMDA receptors prevented the occurrence of that effect. The obtained results suggest that CRF may have anxiolytic-like effects in the frontal cortex. Moreover, the peptide inhibits locomotor and exploratory activity and depresses excitatory synaptic transmission in a NMDA receptor-dependent manner.