Figure 4.

Effect of an intracerebroventrical infusion of the β-adrenergic antagonist propranolol (2 μg in 5 μl) on baseline recordings and on weak and reinforced LTP. (A Upper) The quality of the preparation allowed stable long-term recordings of PS amplitude (PSA) and fEPSP slope (n = 8). (A Lower) The infusion of propranolol did not affect the baseline recordings (n = 7). (B) Propranolol, given 5 min after tetanization (n = 7) did not influence an “unsaturated” LTP in comparison to saline controls (n = 6). (C and D) Application of the β-adrenergic antagonist propranolol 5 min post-tetanically (25 min before water access (n = 6) or footshock (n = 7) prevented the reinforcement of LTP of PSA and fEPSP slope, respectively. Data were plotted as average change from baseline response (mean ± SEM).