Fig. 3

Effects of repeated systemic cocaine and subsequent withdrawal on spontaneous excitatory post-synaptic currents (sEPSCs) and paired pulse ratio. A Average sEPSC frequency in cocaine (coc) and saline (sal) pre-treated groups. In males, cocaine treatment increased sEPSC frequency compared to saline treatment. No effects were found in females. B Cumulative sEPSC frequency distribution in males (top) and females (bottom). Males treated with cocaine show a clear shift in the sEPSC frequency distribution with more events occurring with shorter inter-event intervals, but no such shift in sEPSC frequency distribution was found in females. C Average sEPSC amplitude in cocaine and saline pre-treated groups. sEPSC amplitude was unaffected by cocaine treatment in both groups. D sEPSC Amplitude distribution in males (top) and females (bottom). E Paired pulse ratio in males. Cocaine treatment in males did alter the paired pulse ratio. F Representative paired pulse ratio trace in saline and cocaine-treated males. G Representative sEPSC traces in males (top) and females (bottom) from saline- and cocaine-treated groups. H Locomotor activity in response to cocaine on withdrawal day 14–16 in saline- or cocaine-pretreated females. Cocaine pre-treated females showed stronger cocaine-induced locomotion at both doses tested compared to saline pre-treated females receiving cocaine for the first time. * = Sidak’s post-test p < 0.01; # = main effect of pre-treatment p = 0.03