Bucladesine, PKA activator, is a cyclic nucleotide derivative that mimics the action of endogenous cAMP and is capable of permeating the cell membrane.

PTP Inhibitor I is a cell-permeable, protein tyrosine phosphatase (PTP) inhibitor that covalently blocks the catalytic domain of the Src homology region 2 domain-containing phosphatase (SHP-1(ΔSH2)) with a Ki value of 43 μM and PTP1B with a Ki value of 42 μM.

N tau-methylhistamine is one of the histamine metabolites. N tau-methylhistamine in plasma and urine is a good parameter for histamine release and the determination of this histamine metabolite is generally less hampered by possible artifacts (due to basophil disrupture a very short half-life time or bacterial production) than determinations of histamine itself.