Renal artery responses to trace amines: Multiple and differential mechanisms of action.

Purpose: The rise in consumption of dietary supplements containing the trace amines p-tyramine, p-synephrine and p-octopamine has been associated with cardiovascular side effects. Since renal blood flow plays an important role in blood pressure regulation, this study investigated the mechanisms of action of these trace amines on isolated porcine renal arteries.

Main Methods: Contractile responses to amines were investigated in noradrenaline-depleted rings of porcine main renal arteries in the absence and presence of the α-adrenoceptor antagonist, prazosin (1 μM), β-adrenoceptor antagonist, propranolol (1 μM), or the trace amine-associated receptor (TAAR-1) antagonist, EPPTB (RO-5212773; 100 nM or 100 μM).

HPLC-UV-QDa analysis of Citrus aurantium-labelled pre-workout supplements suggest only a minority contain the plant extract.

Bitter orange (Citrus aurantium) is a common ingredient in pre-workout supplements with purported weight-loss and performance-enhancing effects. Supplements listing Citrus aurantium or p-synephrine have been associated with reports of adverse cardiovascular events attributed to the active biogenic amines, p-synephrine, p-octopamine or p-tyramine. Additionally, questions have been raised as to the authenticity of the plant-derived active components listed on the supplement labels.

Differential mechanisms of action of the trace amines octopamine, synephrine and tyramine on the porcine coronary and mesenteric artery.

Trace amines such as p-tyramine, p-octopamine and p-synephrine are found in low concentrations in animals and plants. Consumption of pre-workout supplements containing these plant-derived amines has been associated with cardiovascular side effects. The aim of this study was to determine the mechanisms of action of these trace amines on porcine isolated coronary and mesenteric arteries.