Fig. 7.

Activation of adenylyl cyclase by forskolin simulates late phase of LTP in the MPP. A, Slices treated with 50 μm forskolin for 15 min showed a gradual potentiation that reached a plateau level ∼45 min after forskolin application. This facilitation persisted for 3 hr during 0.02 Hz test stimulation of the MPP. ACT D (40 μm), a transcription inhibitor, attenuated this facilitation when applied before and during forskolin application. B, In contrast, 50 μm7β-deacetyl-7β-[γ-(morpholino)butyryl]hydrochloride, an inactive forskolin analog, had no effect on baseline field EPSPs evoked at 0.02 Hz. The analog was dissolved in DMSO (0.1% final concentration). Normal magnesium and calcium levels were present in these experiments.