king, etc. Along with objectively groundless emotional symptoms, e.g. fear of losing control, sense of unreality and detachment, even fear of dying they affect PD sufferers, interfering with social and professional aspects oftheir lives. Some PD patients associate panic attacks with certain objects or situations, and therefore phobias, especially agoraphobia , are closely associated with the PD. The ethiology of PD is not clear, and most theories support either a psychological or a neurobiological view. The most developed psychological explanation is cognitive theory of PD. According to Clark's model, the panic attack develops as a result of misinterpretation of unpleasant bodily sensations,which leads to increasing feeling of anxiety and progresses to a fully developed panic. This misinterpretation is defined as anxiety sensitivity, and it present in PD patients. When challenged by panicogenic pharmacological agents, anxiety sensitivity causes a faster and stronger response in PD sufferers than in healthy individuals.2 Biological theories concentrate on implicating pathological disturbances in the neurotransmitter systems, including GABA, serotonin (5HT) and noradrenaline. Recently attention was given to a less known neuropeptide cholecystokinin (CCK). Though it was first discovered in the gastrointestinal tract (it is secreted by the small intestine and stimulates gall bladder contractions), its abundant presence in the mammalian brain indicated on its possible functions as a behavior-regulating neurotransmitter. Various electrophysiological data and animal studies linked CCK to anxiety regulation. For example, its excitatory role on pyramidal neurons of hippocampal area was first observed in rats after electrophoretic administration of CCK, and increased density of CCK-B receptors was detected in rats with low exploratory activity and with novelty-avoidance behavior.7 The later, also known as novelty stress sensitivity,...
