Noradrenaline release enhanced by cholera toxin and pertussis toxin in rat cerebral cortical slices.

The effects of cholera and pertussis toxin on the release of noradrenaline (NA) were studied in the rat cerebral cortex. The cerebral cortical slices were incubated with cholera or pertussis toxin for 2 h, subsequently loaded with 1-[3H]NA and superfused continuously. The pretreatment with cholera toxin significantly (p less than 0.05) enhanced the 20 mM KCl-evoked [3H]NA release. In contrast to a significant (p less than 0.05) increase in [3H]NA release by pertussis toxin, neither A-protomer nor B-oligomer of the toxin could affect the release. These results suggest that cholera and pertussis toxin-substrates, probably guanosine triphosphate-binding proteins, could be involved in the NA release in the central nervous system.