Fig. 5. Spike discharge properties and glutamatergic receptor currents of CA1 pyramidal neurons are not strain dependent. (A) Membrane excitability: plot of the number of action potentials produced during a 1 s current pulse versus current amplitude in each of the four mouse strains. (B) Spike frequency accommodation: plot of spike number (order in a train) versus delay from onset of current injection. These are averages of fifth-order polynomial curve fits of data obtained from B6 (N=13 cells) 129/SvEms (N=28), DBA (N=14) and CBA (N=21) neurons. (C) Sample traces showing spike frequency accommodation in B6 and 129/SvEms cells. Current injections of 300 pA were used to elicit spiking. (D) Left: ratios of N-methyl-D-aspartate (NMDA) to non-NMDA glutamatergic currents were not significantly different between strains (B6, N=14 cells; 129/SvEms, N=12; DBA, N=5; CBA, N=5). Right: a current–voltage plot comparing the voltage dependence of glutamatergic currents measured in B6 and 129/SvEms neurons. Taken from (Nguyen et al., 2000b). (Copyright 2000, The American Physiological Society, used with permission.)