Excessive D1-cAMP/PKA signaling maintains the extended-timing t-LTP in cocaine mice. A, Effect, or lack thereof, of SCH23390 (SCH, 10 μm) on t-LTP induction at +10 ms in cocaine slices. B, Blocking effect of SCH23390 (SCH, 10 μm) on t-LTP at +30 ms in cocaine slices. C, Effect of bath-applied RP-cAMPS (50 μm) on t-LTP induction at +30 ms in cocaine slices. D, Lack of t-LTP induction at +30 ms in cocaine slices when PKI 6–22 (20 μm) was loaded in the patch pipette. E, Lack of t-LTP induction at +50 ms in slices prepared from cocaine mice. F, SKF81297 (SKF, 2 μm) enabled t-LTP induction at +50 ms in cocaine slices. All drugs (except PKI 6–22) were applied to the extracellular bath during EPSP–AP pairings. Scale bars, 2 mV, 20 ms. *p < 0.05, ***p < 0.001 versus Ctrl (+30 ms), unpaired two-tailed t tests; #p < 0.05 vs SKF, unpaired t test with Welch's correction. Ctrl data in G are replotted from Figure 1 for direct comparisons.