Fig. 3
From: A tale of two transmitters: serotonin and histamine as in vivo biomarkers of chronic stress in mice
Dynamical interaction between histamine and serotonin with chronic stress. A Analysis of cytokine ratios (TNF-α/IL-4 and IL-6/IL4, respectively) for male (blue; n = 14) and female (light blue; n = 19) control mice and male (gray; n = 15) and female (light gray; n = 19) CMS mice. Significance was defined as p < 0.05 in a t test. B Schematic showing histaminergic regulation of serotonin via H3 heteroreceptors created with BioRender.com. C Schematic diagram and equations depicting the data-based possible interaction between histamine (HA) and serotonin (5HT), involved in stress-induced depression. D Nullcline plots of serotonin and histamine are obtained for the basal level of I5HT and different levels of IHA. The intersection points of the curves are the global equilibrium points of the system. E Experimental data (solid magenta circles) are obtained from Samaranayake et al. 2016. The theoretical data (solid black circles) have been procured from the nullcline analysis (r2 = 0.93). F Example color plot of histamine FSCV in the hypothalamus. Oxidation of HA can be observed at 0.2 V (green event). Stimulation is marked by a purple box at 5–7 s. Averaged evoked hippocampal HA release for control (orange; n = 6) and CMS-treated mice (red; n = 5) is shown