Cholecystokinin in the C57BL/6J Mouse: Effects on Acoustic Startle Response and Anatomical Distribution in the Amygdala

Cholecystokinin (CCK) causes panic attacks in humans and increases fear-associated behaviours in rodents by way of CCK-B receptors. The aim of this thesis was to investigate the CCK system behaviourally and anatomically in C57BL6/J mice and to assess the suitability of CCK-IRES-Cre mouse lines for amygdala manipulation. The behavioural results failed to support the startle-activating effect of CCK-4 or the startle-inhibiting effects of CCK-B receptor antagonists, in spite of evidence showing CCK-4 induced activation of c-Fos in the central amygdala. The anatomical results show that CCK-8 expression in the basolateral amygdala (BLA) is comparable to the CCK mRNA expression pattern. These results suggest that viral manipulations in the CCK-IRES-Cre line will induce changes in endogenous CCK systems in the mouse amygdala.MAS