Fig. 7
From: The sigma-1 receptor modulates methamphetamine dysregulation of dopamine neurotransmission
σ1R activation decreases the effects of METH on reward thresholds. a Experimental timeline for intracranial self-stimulation (ICSS) experiments is shown. b Schematic demonstrating ICSS testing is shown. Rodents receive a non-contingent pulse at a given frequency and are given 7.5 s to respond. Positive responding by the rodents results in a contingent pulse at the same frequency as the non-contingent pulse. The reward threshold is defined as the minimal frequency required to elicit a response. Rat image is courtesy of Servier Medical Art, licensed under CC BY 3.0 (https://creativecommons.org/licenses/by/3.0/legalcode). c The dose–response studies revealed METH dose-dependently lowers brain rewards thresholds in rats as measured via ICSS. Data is presented as percent vehicle control (n = 8 rats; F (7, 28) = 3.479, P = 0.0083, repeated measures one-way ANOVA; Dunnett’s test for multiple comparisons against control, *P < 0.05). d PRE-084 treatment attenuated the METH-induced (0.3 mg/kg) decrease in brain reward thresholds (n = 6 saline rats, 8 METH rats; F (1,12) = 75.23, P < 0.0001, two-way ANOVA; Bonferroni’s test for multiple comparisons, **P < 0.01 saline vs. METH; + P < 0.05 indicates a higher brain threshold compared to METH and 3 mg/kg of PRE-084). Data is represented as mean ± SEM
