4-Hydroxytryptamine creatinine sulfate, a derivative of tryptamine, acts as an agonist for neurotransmitters.

4-Hydroxytryptamine creatinine sulfate administered intravenously via the tail vein, alongside a constant dose of [3 H] norepinephrine, to 17-20 g male albino mice, reduces the uptake of [3 H] norepinephrine, exhibiting an effective dose (ED50) of 35 μmoles/kg[1]. When given as a subcutaneous injection, with a pretreatment of [3 H] norepinephrine administered intravenously 60 minutes prior, it elevates the ED50 to 21 μmoles/kg for the release of [3 H] norepinephrine in monoamine oxidase-inhibited mice[1].