On the Role of Cholecystokinin (CCK) in Fear and Anxiety: A Review and Research Proposal - On the Role of Cholecystokinin (CCK) in Fear and Anxiety: A Review and Research Proposal - Open Access Pub

Cholecystokinin (CCK) is found in high concentrations in cortical and limbic structures including the amygdala of rodents, and evidence has been gathered supporting a role for CCK in the neurobiology of anxiety. A variety of animal models have been used to study a central state of fear or anxiety, state that appears to produce a complex pattern of behaviors highly correlated with each other. It is now well established that the amygdala in particular is a critical link in the pathway through which sensory stimuli come to acquire fear evoking properties. The purpose of the proposed experiments is to study the role of the putative neurotransmitter CCK in fear and anxiety in vivo by means of a methodology coupling electrochemical and electrophysiological measurements in various brain areas. Indeed, the association of in vivo differential pulse voltammetry (DPV) with in vivo extracellular single unit recording could be able to provide concomitant physiological and neurochemical indications and to relate them to behavioral events. To further study and support the initial observations pharmacological experiments will also be performed by means of CCK receptor agonists and antagonists. This may eventually lead to development of more effective pharmacological strategies for treating clinical anxiety disorders. DOI10.14302/issn.2644-1101.jhp-19-2766 A variety of animal models have been used to study a central state of fear or anxiety. In some models fear is inferred when an animal freezes, thus interrupting an ongoing behavior such as pressing a bar or interacting socially with other animals. In other models fear is measured by changes in autonomic activity, such as heart rate, blood pressure, or respiration. Fear can also be measured by a change in simple reflexes or a change in facial expressions and mouth movements. Thus fear or anxiety appears to produce a complex pattern of behaviors that are highly correlated with each other. A Behavioral Model to Study Fear and Anxiety Classical conditioning paradigms are widely used to study emotional mechanisms of the brain 1, 2, 3, 4, 5. Fear conditioning is a form of Pavlovian classical conditioning. It is produced experimentally by arranging the occurrence of an insignificant or emotionally neutral sensory stimulus, the conditioning stimulus (CS), with an aversive stimulus, the unconditioned stimulus (US). The CS, by virtue of its relationship with the US, acquires aversive properties and comes to obtainresponses characteristically elicited by threatening stimuli. Thus, a tone that has been previously been paired with