Ergot alkaloids and phosphodiesterase; 'in vitro' activities in several rat brain areas

The 'in vitro' activity of ergotamine, dihydroergocristine, dihydroergocornine and dihydroergocryptine on the phosphodiesterase system at low and high Km in several rat brain areas was examined. These drugs were found to exert an inhibitory effect in all the areas examined with regard to both systems, and particularly on low substrate concentration phosphodiesterases.