Cholecystokinin modulation of [3H]noradrenaline release from superfused hypothalamic slices

Interactions between cholecystokinin (CCK) and noradrenaline (NA) have been studied by investigating the effect of sulphated cholecystokinin octapeptide (CCK-8) on potassium (K+)-stimulated release of [3H]NA from superfused hypothalamic slices. NA and the alpha 2-agonist clonidine markedly inhibited [3H]NA release, while the alpha-antagonist yohimbine facilitated the release process. CCK was found to give a significant, albeit small, inhibition of [3H[NA release, which was maximal at a concentration of 10(-8) M. These results provide evidence that CCK-8 can exert an inhibitory effect on hypothalamic NA transmission and offer one possible mechanism for the interaction of CCK and NA in the hypothalamic control of food intake.