Figure 4.

A1R activation blocks glu-LTD in cerebellar Purkinje cells. A, A1R-selective agonists blocks glu-LTD in cultured Purkinje cells. Each pair of traces indicates sample glutamate-evoked currents of a cell before and after the conjunctive depolarization and glutamate iontophoresis in the absence (Control) or continuous presence of the A1R-selective agonist R-PIA (100 nm) or CCPA (500 nm). I_glu was monitored under voltage clamp at −70 mV. The conjunctive stimuli were 12 sets of simultaneous depolarizing voltage jumps (0 mV, 3 s) and glutamate iontophoresis. Each plot indicates the time course of the mean peak amplitude of I_glu. B, The endogenous A1R agonist adenosine blocked glu-LTD in a concentration-dependent fashion. Each pair of traces indicates sample I_glu of a cell before and after the conjunctive stimuli in the continuous presence of the labeled dose of adenosine. Each plot indicates the time course of the mean peak amplitude of I_glu. Scale bars, 1 s and 100 pA. White bars, timing of the conjunctive stimuli; dots and error bars, mean ± SEM of the data for every 2 min period.