iteria and were asked to describe any additional symptoms experienced during a panic attack. The occurrence of a panic attack was recorded only in case of abrupt onset and assessment results consistent with criteria for at least moderate panic attack according to DSM-III-R. Resemblance of a natural panic attack was taken into consideration only for PD patients. Results showed that PD sufferers have enhanced sensitivity to CCK-4. When injected with 25 g of CCK-4, 91 % of them panicked in comparison with 17% from control group. The panic rate reached 100% with the 50 g dose, while only 47% of healthy volunteers panicked. Only 2 out of 23 PD patients (9%) panicked on placebo and none of the controls did.It 's worth mentioning that similar effects were observed in the studies of CCK-4 agonist pentagastrine, a peptide which includes aminoacid sequence identical to CCK-4. Panic attacks occurred in 60-80% of PD patients and only in 25% of healthy participants. The double blind placebo controlled study similar to Bradwejn's group showed higher sensitivity to pentagastrin in PD patients (van Megen et al., 1993), though the dose effect was not observed.7 Effect of CCK-antagonistsTo further investigate mechanism of CCK-induced anxiety in humans, research progressed to the employment of synthetic CCK-B antagonists. These antagonists have selective affinity for CCK-B receptors and are able to counteract the effect of CCK-4. Among the most studied antagonists are L-365,260 and CI-988. The first one belongs to the benzodiazepine class of drugs. and the second one is a peptoid. The most often cited study of true experimental design was conducted by Dr. Bradwejn research team.4 All participants were affected by PD. The experiment had a double-blind placebo arrangement and subjects were referred by two teaching hospitals from Canada and Netherlands. L-365, 260, a selected CCK-B antagonist of choice was given to participants orally in two d...
