Article Figures & Data
Figures
- Fig. 1.
Temperature-dependent changes in astrocyte transporter currents. A, Outside-out patch removed from an astrocyte located in stratum radiatum of area CA1. Solid lines in A and B are the control responses recorded at room temperature, and dotted linesare the responses of the same patch recorded at 36°C.Inset, Response at 36°C has been scaled to that in control and shown at a faster time base to illustrate the time course of the two responses. B, Response of a different patch to d-aspartate (10 mm). Tracesare illustrated as in A. Traces are averages of 8–12 consecutive responses recorded at −90 mV. KSCN-based internal solution. The open tip response above eachtrace indicates the duration of the agonist application.
- Fig. 2.
Recovery time course ofl-glutamate-evoked transporter currents. A,B, l-glutamate (10 mm) was applied for 30 msec to an outside-out patch from an astrocyte and then reapplied for 20 msec after a variable delay, at both 24°C (top traces) and 36°C (bottom traces).Traces are averages of six consecutive responses recorded at −90 mV. KSCN-based internal solution. C, Summary plot of the ratio of the peak amplitude of the second pulse (P2) over the peak amplitude of the control response (P1) for recordings made at both 24°C (n = 4) and 36°C (n = 11). The four patches used to measure the recovery at 24°C were also used to measure the recovery at 36°C.
- Fig. 3.
Recovery time course ofd-aspartate-evoked transporter currents. A,B, d-aspartate (10 mm) was applied to an outside-out patch from astrocytes for 30 msec and then reapplied for 20 msec after a variable delay, at both 24°C (top traces) and 36°C (bottom traces).Traces are averages of five consecutive responses recorded at −90 mV. KSCN-based internal solution. C, Summary plot of the ratio of the peak amplitude of the second pulse (P2) over the peak amplitude of the control response (P1) for recordings made at both 24°C (n = 4) and 36°C (n = 10). The four patches used to measure the recovery at 24°C were also used to measure the recovery at 36°C.
- Fig. 4.
Temperature-dependent changes in evoked responses.A, Synaptically activated transporter current (STC) recorded from a stratum radiatum astrocyte.Vm = −96 mV. K-methanesulfonate-based internal solution. B, AMPA receptor-mediated EPSCs recorded from a CA1 pyramidal neuron. Vm = −80 mV. Cs-methanesulfonate-based internal solution. C, Field EPSPs (fEPSP) recorded in stratum radiatum of area CA1. A–C, Solid lines are the responses recorded at room temperature, and the dotted lines are the responses recorded at 36°C.
- Fig. 5.
Transporter currents are not associated with EPSCs in CA1 pyramidal neurons. The ionotropic glutamate receptor antagonists NBQX (10 μm) and d,l-CPP (10 μm) completely blocked evoked responses, at both 24°C and 36°C. The brief inward current observed in NBQX and CPP is attributable to the increased amplitude and slower decay of the stimulus artifact at 36°C. Vm = −90 mV. ACSF contained picrotoxin (100 μm) and SR-95531 (5 μm). KSCN-based internal solution.
- Fig. 6.
Transporter currents are not detected in pyramidal cell patches. A, Outside-out patch from a CA1 pyramidal neuron. l-glutamate (10 mm) activates inward (Vm = −90 mV) and outward (Vm = 90 mV) (A1 ) currents that are completely blocked by NBQX (10 μm), GYKI-52466 (25 μm), and d,l-CPP (10 μm) (A2 ). B,l-glutamate (10 mm) activates transporter currents in outside-out patches from CA1 astrocytes (B1 ), which were not affected by NBQX (10 μm), GYKI-52466 (25 μm), andd,l-CPP (10 μm) (B2 ). Responses were recorded at −90 mV and +90 mV, as in A. All solutions contained 20 μmglycine. Traces are averages of 8–12 consecutive responses. A KSCN-based internal solution was used for both recordings.
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