aminoacid main role
fast/slow excitation and inhibition
catecholamine main role
fast/slow transmission and modulation
peptides main role
modulation
lipids/steroids main role
modulation and plasticity
small molecules main role
modulation
autocrine as a form of chemical signalling
cell targets itself
paracrine as a form of chemical signalling
cell targets nearby cell
endocrine as a form of chemical signalling
cell targets distant cell through bloodstream