Figure 2.

The effects of PKA inhibition on SV recycling are reversible. A, B, Rat hippocampal neurons were incubated for 30 min with H89 and subsequently loaded with FM4-64 by exposure to 55 mm KCl for 1 min (left column). After a 30 min incubation in the absence of H89 to recover from PKA inhibition and bleaching of the residual fluorescence, a second pulse of FM4-64 uptake was induced with the same depolarizing protocol (right column). Note the variability among individual synapses in the SV recycling activity reached on recovery from PKA inhibition (arrowheads in B). Scale bar: A, 15 μm; B, 5.5 μm.