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. 1999 Mar 1;515(Pt 2):453–462. doi: 10.1111/j.1469-7793.1999.453ac.x

Figure 3. Brief exposure to NO has long-lasting consequences for both NMDA receptor-mediated transmission and the induction of LTP.

Figure 3

A, the percentage change in the slope of responses evoked by stimulation of two independent afferent pathways (P1, •; P2, ○) is displayed as a function of time. Mean data obtained from 5 slices are plotted, normalized to the mean of the control period prior to delivery of conditioning stimuli. The s.e.m. is plotted for every fifth mean. Slices were perfused with 500 μM caged NO throughout. After a 20 min control period a conditioning tetanus was applied to P1 (▴) followed 10 min later by a 1 ms pulse of near-UV light releasing 4.5 μM NO (arrow). Conditioning tetani ▵ applied to P2 at 10, 70 and 130 min after photolysis failed to induce LTP. B, the mean slope of NMDA receptor-mediated responses is plotted against time (pooled data from 4 slices) and the s.e.m. is plotted for every fifth mean. The slices were bathed with 400 μM caged NO throughout. A single 1 ms pulse of near-UV light (arrow) releasing 3.6 μM NO produced a marked and persistent decrease in the efficacy of NMDA receptor transmission. Bath application of 25 μM D-AP5 abolished the NMDA receptor-mediated potential (horizontal bar). The NMDA receptor-mediated potentials were isolated pharmacologically in nominally magnesium-free ACSF containing 10 μM CNQX. Experiments performed at 24 °C.