Table 1.

Names of variables

In equations and text	Full name
bh2	Dihydrobiopterin
bh4	Tetrahydrobiopterin
trp	Tryptophan
btrp	Blood tryptophan
htp	5-Hydroxytryptamine
cht	Cytosolic serotonin
vht	Vesicular serotonin
eht	Extracellular serotonin
hiaa	5-Hydroxyindoleacetic acid
pool	The tryptophan pool
$G_{\mathit{ht}}^{\ast }$	Serotonin activated G-protein
$T_{\mathit{ht}}^{\ast }$	Serotonin activated T regulatory protein
$B_{\mathit{ht}}$	Serotonin autoreceptors bound to eht
ght	Glial serotonin
$G_{\mathit{ha}}^{\ast }$	Histamine activated G-protein
$T_{\mathit{ha}}^{\ast }$	Histamine activated T regulatory protein
$B_{\mathit{ha}}$	Histamine autoreceptors bound to eha
eha	Extracellular histamine