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. 2000 Aug 15;20(16):5924–5931. doi: 10.1523/JNEUROSCI.20-16-05924.2000

Fig. 1.

Fig. 1.

Coactivation of β-adrenergic and cholinergic receptors enhances the induction of LTP by a short train of 5 Hz stimulation. A, A 5 sec train of 5 Hz stimulation (delivered at time 0) by itself induced only a small potentiation of synaptic transmission (open symbols; fEPSPs potentiated to 120.5 ± 7.12% of baseline;n = 6; p < 0.05, pairedt test comparison to pre-5 Hz baseline) but induced robust LTP (filled symbols; fEPSPs potentiated to 175.6 ± 11.2% of baseline; n = 6) when delivered at the end of a 10 min bath application of ISO plus carbachol (CCh) (200 nm each; presence in bath indicated by the bar). Traces show fEPSPs recorded during baseline and 45 min after 5 Hz stimulation in a control experiment (5 Hz stimulation alone, lefttraces) and in an experiment in which 5 Hz stimulation was delivered in the presence of ISO plus carbachol (right traces). Calibration: 2 mV, 5 msec. B, Summary of the effects of 5 Hz stimulation on synaptic strength when 5 Hz stimulation was delivered alone (open bars; data from the experiment shown in A) or at the end of a 10 min application of ISO (n = 6), carbachol (n = 6), or ISO plus carbachol (data from the experiment shown in A). Although coapplication of ISO plus carbachol significantly enhances the amount of LTP induced by 5 Hz stimulation (*p < 0.05), neither ISO alone nor carbachol alone significantly enhances LTP induction (fEPSPs were potentiated to 125.4 ± 7.9% and 112.9 ± 4.1% of baseline, respectively).