Fig. 2.
A, PACAP has a dual, potentiating, and inhibitory effect on NMDA-induced channel activity in outside-out patch recordings from SCN neurons. A patch was held at −60 mV and exposed to 20 μm NMDA–100 nm glycine in the absence and presence of two concentrations of PACAP. a, Sample trace of activity in the presence of NMDA–glycine alone.b, Trace during exposure to NMDA–glycine and 10 pm PACAP demonstrating increased activity.c, Trace during exposure of the same patch to NMDA–glycine and 100 nm PACAP showing the pronounced reduction in Popen. B, Dose-dependent effects of PACAP on NMDA channel activity. Outside-out patches, held at −50 to −60 mV, were exposed to 20 μmNMDA–100 nm glycine. Values for the proportion of time spent in open configurations were assessed for channels in the absence and presence of varying concentrations of PACAP, and potentiations and inhibitions were calculated as percentages above and below control activity levels. Symbols indicate means, and error bars indicate SEMs. Each point is averaged from at least five outside-out patch recordings.