Table 1.

Effects of KB R7943 and CGP 37157 on presynaptic [Ca2+]i and short-term synaptic enhancement

MeasurementControlKB R7943 (20 μm)CGP 37157 (25 μm)
FirstSecondBefore drugAfter drugBefore drugAfter drug
Pretetanic EJP amplitude (mV)0.22  ± 0.020.23  ± 0.02 (8)0.17  ± 0.030.17  ± 0.02 (8)0.19  ± 0.020.20  ± 0.02 (6)
Peak EJP amplitude during tetanus (mV)10.54  ± 0.4110.51  ± 0.41 (8)11.93  ± 0.759.77  ± 0.80 (8)1-16010.28  ± 1.010.48  ± 1.0 (6)
EJP amplitude 1 min after tetanus (mV)1.53  ± 0.131.63  ± 0.11 (8)1.55  ± 0.180.79  ± 0.12 (8)1-1601.03  ± 0.101.15  ± 0.14 (6)
EJP amplitude 5 min after tetanus (mV)0.68  ± 0.0930.65  ± 0.063 (8)0.79  ± 0.170.38  ± 0.08 (8)*0.76  ± 0.090.74  ± 0.07 (6)
PTP decay time constant (min)4.84  ± 0.514.62  ± 0.41 (8)4.75  ± 0.313.22  ± 0.43 (8)1-1604.12  ± 0.304.19  ± 0.33 (6)
Pretetanic [Ca2+]i (μm)0.15  ± 0.020.16  ± 0.03 (4)0.15  ± 0.020.15  ± 0.01 (5)0.15  ± 0.020.17  ± 0.03 (4)
Peak [Ca2+]i during tetanus (μm)1.54  ± 0.091.57  ± 0.13 (4)1.65  ± 0.161.34  ± 0.13 (5)1-1601.53  ± 0.051.52  ± 0.06 (4)
[Ca2+]i1 min after tetanus (μm)0.78  ± 0.070.78  ± 0.08 (4)0.78  ± 0.020.55  ± 0.03 (5)1-1600.77  ± 0.010.78  ± 0.01 (4)
[Ca2+]i 5 min after tetanus (μm)0.34  ± 0.040.34  ± 0.01 (4)0.40  ± 0.040.26  ± 0.043 (5)*0.36  ± 0.040.33  ± 0.03 (4)
Slow [Ca2+]i decay time constant (min)5.66  ± 0.625.63  ± 1.45 (4)5.71  ± 0.693.30  ± 0.71 (5)*5.07  ± 1.485.93  ± 1.03 (4)
Pretetanic [Na+]i(mm)7.937.677.91  ± 0.677.96  ± 0.75 (3)
Peak [Na+]i during tetanus (mm)80.680.580.6  ± 5.3282.6  ± 3.27 (3)
[Na+]i 5 min after tetanus (mm)33.236.436.8  ± 4.3457.7  ± 2.47 (3)*
[Na+]i decay time constant (min)7.667.198.52  ± 1.9213.44  ± 2.08 (3)*

  • Postsynaptic EJP amplitude and presynaptic [Ca2+]i or [Na+]iin boutons were measured before and after tetanic stimulation. Data: mean ± SE; numbers of measurements in parentheses; significant changes by Student's paired t test;

  • ↵* p < 0.05;

  • ↵F1-160 p < 0.01.