IN-VIVO MICRODIALYSIS OF CORTICOTROPIN-RELEASING FACTOR (CRF) - CALCIUM-DEPENDENCE OF DEPOLARIZATION-INDUCED NEUROSECRETION OF CRF

Corticotropin releasing factor (CRF) is a large neuropeptide which functions as a major neurotransmitter in physiological stress responses. We have developed a microdialysis method for detecting CRF release from the median eminence of anesthetized rats. Depolarizing concentrations of KCl increased release of CRF into the perfusion media; this effect was inhibited by 100 muM verapamil. Our characterization of the physiologic conditions of KCl-induced release of neuronal CRF using the microdialysis technique provides evidence that the CRF release system is Ca2+-dependent and maintains its integrity over many hours in anesthetized rats.