Figure 6.

Learning-facilitated LTP in mossy fiber synapses is regulated by β-adrenergic receptors. (A) In control experiments, application of sHFS (two trains of 100 pulses given at 100 Hz) in the absence of a novel holeboard (and in the presence of vehicle) elicits STP. The combination of sHFS with novel holeboard exploration facilitates STP into LTP. Injection of propranolol before novel exploration of an empty novel holeboard elicits STP that is similar to that seen in vehicle-injected controls. A second exposure to the holeboard (ca. one week after the original treatment with propranolol) facilitates LTP. Line breaks indicate changes in time scale. (B) Analog traces recorded (i) 5 min pre-sHFS, (ii) 5 min post-sHFS, and (iii) 24 h post-sHFS, from a vehicle-injected animal in the absence of holeboard (left upper panel), from a propranolol-treated animal that was exposed to a novel empty holeboard (right upper panel), from an animal that was re-exposed to a novel empty holeboard ca. one week after the treatment with propranolol (lower left panel) and from an animal that was exposed to a novel holeboard for the first time (lower right panel). Vertical scale bar: 2 mV, horizontal scale bar: 6 ms.